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Missouri S&T Laboratory Chemical Hygiene Plan
Table of Contents
Section 1-Chemical Hygiene Plan
Section 2- Standard Operating Procedures for Working with Chemicals
Section 3- Information for Work with Chemicals of Specific Hazard Class
Section 4- Chemical Toxicology
Section 5- Glossary of Terms
Appendix A -Peroxide Test Protocol
Appendix B -Hydrofluoric Acid Guidelines
Appendix C -Select Carcinogens List
Appendix D -Nanomaterials Guidelines
Section 1- Chemical Hygiene Plan
1.1 Introduction (back to top)
The Missouri University of Science and Technology (Missouri S&T) is committed to providing a safe learning and working environment for our students and employees. As part of this commitment, this Chemical Hygiene Plan has been developed to establish a standard format for chemical safety in the laboratories of the university following the guidance of the Occupational Safety & Health Administration (OSHA) Laboratory Safety Standard (29 Code of Federal Regulations (CFR) 1910.1450). The standard was developed to ensure that laboratory employees are informed about the hazards associated with the chemicals used in their work area and that appropriate work practices and procedures are in place to use these chemicals in a safe and informed manner based on the known hazards for the chemicals. This plan will ensure personnel will be trained and learn to recognize and comply with workplace safety requirements.
The standard operating procedures (lab practices and engineering controls) recommended by this plan identify safeguards that should be taken when working with hazardous materials. These safeguards will protect workers in a majority of situations. In some instances the physical or chemical properties, the proposed use, the quantity of material used or the toxicity will require more controls than this plan provides. Professional judgment is an essential requirement for interpretation of these operating procedures and individual laboratories will need to modify these procedures to meet the requirements of their specific research and operational needs.
For instance, for certain hazards and classes of chemicals not covered under the General Standard Operation Procedures for working with chemicals, principal investigators and/or department chemical hygiene officers/lab supervisors must develop their own site specific standard operating procedures (SOP). These site-specific SOPs must be kept with the hard copy of the laboratory chemical hygiene plan inside the corresponding lab.
The implementation of this plan and development of lab specific procedures should result in a safer work and learning environment for employees and students.
1.2 Chemical Hygiene Responsibilities (back to top)
Responsibility for chemical health and safety rests at all levels at the university. A detailed listing of management responsibilities is found in the overall lab safety program manual and applies to this chemical hygiene plan as well. The responsibilities of supervisors, lab employees and the department of Environmental Health and Safety under this plan are as follows:
Designate a Chemical Hygiene Officer for department; communicate with faculty, staff, students, and visitors to ensure responsibilities are carried out, monitor implementation of the program; provide resources to support safety program.
Chemical Hygiene Officer (CHO)
Develop, implement and revise this chemical hygiene plan, policies and practices. Maintain an awareness of current requirements concerning regulated substances. Responsible for program oversight.
- Monitor purchasing, use, and disposal of chemicals and biological materials used in these laboratories.
- Assure appropriate records are maintained (training, audit reports, injury reports etc.).
- Ensure that faculty, staff and students know and follow the chemical hygiene rules.
- Conduct regular formal laboratory hygiene and housekeeping inspections including routine inspections of any emergency equipment required by this plan for this laboratory.
- Assist the PI in determining the required or appropriate levels of protective apparel and equipment.
Principal Investigator (PI)
- Maintain an awareness of current requirements concerning regulated substances. Responsible for daily operations.
- Monitor purchasing, use, and disposal of chemicals and biological materials used in these laboratories.
- Assure appropriate records are maintained for the individual lab if required (e.g. training, audit reports, injury reports etc.).
- Ensure that individuals working in this laboratory know and follow the chemical hygiene rules.
- Provide informal daily laboratory and housekeeping inspections including any emergency equipment as required.
- Develop laboratory specific operating procedures based on chemical and physical hazards associated with lab operations.
- Determine the required or appropriate levels of personal protective equipment (PPE). Make sure this equipment is in good working order and make sure it is used properly and that all personnel receive the necessary training needed to properly use equipment.
- Ensure that facilities and training for use of any new materials being ordered are adequate for the material.
- Seek ways to improve the hygiene plan.
- Plan and conduct each experiment in accordance with the laboratory chemical hygiene plan and procedures.
- Determine any additional safety considerations needed, carefully consider each aspect of the experiment, even if it is a protocol you do repeatedly and which you are very familiar.
- Develop and practice good personal chemical hygiene habits.
- Attend all required training.
- Be aware of the hazards of the materials worked with and handle those materials in a safe manner. Wear all required PPE.
- Report unsafe conditions to supervisor, or the department chemical hygiene officer.
- Attend all training sessions and follow all standard operating procedures for working in a laboratory.
- Wear personal protective equipment as directed by principal investigator.
- Report to the teaching assistant, faculty member, or department chemical hygiene officer/laboratory supervisor any accidents that result in the exposure to toxic chemicals, and any action or condition that may exist that could result in an accident.
Environmental Health and Safety
- Evaluate and implement safety policies and review new and existing equipment and operating practices to minimize hazards from fire, electricity, hazardous materials, explosion, pressure, and machinery.
- Conduct accident investigations and suggest remedial measures and procedures.
- Hazardous waste disposal services for chemical, biological, and radioactive materials.
- Training and assistance are available as required.
- Oversight and control of physical hazards in the workplace, including general and laboratory safety.
All members of the University should feel free to consult with the Department of Environmental Health and Safety (EHS) at anytime regarding potential toxic chemical, microbiological or radiation exposure. EHS services are available in both emergency and advisory capacities to answer questions from anyone at the University. However, procedures for the safe use and disposal of chemicals or radioactive substances start in the laboratory with students and staff. They must be informed about their responsibilities and the procedures to be followed by the Principal Investigator.
In the event of an emergency, please call the University Police at 911.
1.3 Definitions (back to top)
A laboratory is defined as a facility in which hazardous chemicals are handled or manipulated in reactions, transfers, etc. in small quantities on a non-production basis. Typically multiple chemical procedures are used.
Any element, chemical compound, or mixture of elements and/or compounds which is a physical hazard or health hazard regardless of quantity.
A chemical is a physical hazard if there is scientific, valid evidence that it is a combustible liquid, a compressed gas, an explosive, an organic peroxide, an oxidizer or pyrophoric, flammable, or reactive.
A chemical is a health hazard if there is statistically significant evidence, based on at least one study conducted in accordance with established scientific principles that acute or chronic health effects may occur in exposed employees.
Classes of health hazards include:
- Reproductive toxins (teratogens)
- Neurotoxins (nerve)
- Hepatotoxins (liver)
- Nephrotoxins (kidney)
- Agents that act on the hematopoietic system (blood)
- Agents that damage the lungs, skin, eyes, or musuc membranes
The chemical container label will indicate if the chemical is hazardous. Look for key words like caution, hazardous, toxic, dangerous, corrosive, irritant, carcinogen, etc. Chemicals manufactured or acquired prior to 1985 may not contain appropriate warnings. Always consult the Safety Data Sheet (SDS) prior to using a chemical to identify the hazards associated with the material.
1.4 Training and Information (back to top)
Chemical Safety Training
All employees exposed or potentially exposed to hazardous chemicals while performing their laboratory duties should read and understand the Missouri S&T chemical hygiene plan. All new graduate students should have additional training or guidance from their supervisor prior to beginning lab work.
A laboratory safety training course is offered by Environmental Health and Safety twice per year before the beginning of the fall and winter semesters, and is also available on Blackboard by request.
The training program shall include information on:
- Physical and health hazards of various classes of laboratory chemicals handled;
- Methods/procedures for safely handling and detecting the release of hazardous chemicals present in the laboratory;
- Appropriate spill response;
- Chemical safety policies;
- Applicable details of the Chemical Hygiene Plan (e.g. Standard Operating Procedures (SOPs), etc.)
When a non-routine task is to be performed by an employee for which they have not received training, the employee's supervisor is responsible for informing the employee about the hazards of the task and any special measures (e.g. personal protective equipment (PPE) or engineering controls that may be required to protect the employee.
Every lab worker should know the location and proper use of available PPE and emergency equipment and procedures. Information on protective clothing and equipment is contained in Section 2.3 of this manual.
Students, visitors, and other authorized personnel must receive appropriate training prior to working in any laboratory where hazardous chemicals are stored or used.
There are many sources of safety information available. Health and Safety references are available in the EHS office and the labels on the containers of chemicals offer a great deal of information. The best source for chemical specific data is the SDS for the chemical that will be used in the lab. SDS's are available on the web and several vendors can be accessed from the EHS website:ehs.mst.edu. However, it is strongly suggested that hard copies of the SDS's for the material with greatest hazards be readily available in the lab in a clearly labeled notebook. Otherwise, a computer must be available to all lab workers in order to access the information. Laboratory signage is also a good source of information about the hazards present in the laboratory.
If you find a container with no label, report it to your supervisor. Also report labels that are torn or illegible so the label can be replaced immediately. Never remove the manufacturer label from a container unless the container is completely empty, rinsed, and being used for another purpose. Always read the label and SDS on newly purchased material and become familiar with its hazards.
Safety Data Sheets (formerly known as Material Safety Data Sheets or MSDSs)
The Hazard Communication Standard (HCS) requires chemical manufacturers, distributors, or importers to provide Safety Data Sheets (SDSs) to communicate the hazards of hazardous chemical products. As of June 1, 2015, the HCS will require new SDSs to be in a uniform format, and include the section numbers, the headings, and associated information under the headings below:
Section 1, Identification includes product identifier; manufacturer or distributor name, address, phone number; emergency phone number; recommended use; restrictions on use.
Section 2, Hazard(s) identification includes all hazards regarding the chemical; required label elements.
Section 3, Composition/information on ingredients includes information on chemical ingredients; trade secret claims.
Section 4, First-aid measures includes important symptoms/ effects, acute, delayed; required treatment.
Section 5, Fire-fighting measures lists suitable extinguishing techniques, equipment; chemical hazards from fire.
Section 6, Accidental release measures lists emergency procedures; protective equipment; proper methods of containment and cleanup.
Section 7, Handling and storage lists precautions for safe handling and storage, including incompatibilities.
Section 8, Exposure controls/personal protection lists OSHA's Permissible Exposure Limits (PELs); Threshold Limit Values (TLVs); appropriate engineering controls; personal protective equipment (PPE).
Section 9, Physical and chemical properties lists the chemical's characteristics.
Section 10, Stability and reactivity lists chemical stability and possibility of hazardous reactions.
Section 11, Toxicological information includes routes of exposure; related symptoms, acute and chronic effects; numerical measures of toxicity.
Section 12, Ecological information*
Section 13, Disposal considerations*
Section 14, Transport information*
Section 15, Regulatory information*
Section 16, Other information, includes the date of preparation or last revision.
*Note: Since other Agencies regulate this information, OSHA will not be enforcing Sections 12 through 15 (29 CFR 1910.1200(g)(2)).
Source of above information: www.osha.gov/Publications/HazComm_QuickCard_SafetyData.html
1.5 Chemical Exposure Assessment (back to top)
As chemicals are used for relatively short periods of time and in small quantities, regular environmental or employee exposure monitoring of airborne concentrations is not practical. However, sampling is appropriate when a highly toxic substance is used regularly (3 or more separate handling times per week) or if the material is used for an extended period of time (more that 3-4 hours at a time). An assessment should also be conducted if a highly toxic material is used in large quantities. (29 CFR 1910.1450 (d))
EHS will assess exposures to employees who suspect and report that they have been overexposed to a toxic chemical or are displaying symptoms of over exposure to toxic chemicals. The assessment will initially be qualitative and, based on the professional judgment of safety personnel, may be followed with specific quantitative monitoring. A report documenting this assessment will be issued to the employee, along with any results of monitoring that was conducted. Individual concerns about excessive exposures occurring in laboratories should be brought to the attention of your supervisor or EHS immediately.
1.6 Chemical Hood Evaluation (back to top)
All laboratory ventilation hoods used for control of air contaminants will be tested annually to assure adequate airflow is being maintained to provide necessary protection against employee over-exposure. Hood airflow will be considered adequate when the average face velocity equals a minimum of a 75 linear feet/minute with the hood sash at a working height (14-20 inches). Results of laboratory ventilation tests shall be recorded and maintained by EHS.
1.7 Respiratory Protection Program (back to top)
Inhalation hazards are controlled through the use of respirators or ventilation systems. Check the SDS for inhalation hazards and ventilation requirements. Control of inhalation hazards is best accomplished with engineering methods (hoods, ventilation). Respirator efficiency depends on faculty, staff, and student work practices and training. Prior to respirator use faculty, staff, and students should receive a medical evaluation and be fit tested and trained to ensure proper fit and selection of the respirator for the material in use. For more information on respiratory protection and respirator use refer to the Respiratory Protection Manual.
Section 2- Standard Operating Procedures for Working with Chemicals
2.1 Good Work Practices /Procedures for Handling Laboratory Chemicals (back to top)
Carefully read the label before using any chemical. Also read the manufacturers or supplier's SDS for any special handling instructions and hazards associated with the material. Be aware of potential hazards present in the lab and the appropriate safety precautions. This may include what other lab workers and students are working with, so pay attention to others working in the lab. Know the location and proper use of emergency equipment, the appropriate procedures for responding to emergencies, and the proper methods for storage and disposal of chemicals within the laboratory.
DO NOT WORK ALONE IN THE LABORATORY WITH HAZARDOUS MATERIAL OR PROTOCOLS. If you must work alone or in the evening, work only with non-hazardous materials and obtain permission from your principal investigator and let someone know you will be in the lab so they may check on you periodically.
Label all secondary containers with appropriate identification and hazard information. Use only those chemicals for which you have the appropriate exposure controls and administrative programs/procedures (training, restrictive access, etc.). Always use adequate ventilation. Operations using large quantities (>500 ml) of volatile substances with exposure limits at or below 50 ppm should be performed in a chemical hood.
Use hazardous chemicals and all laboratory equipment only as directed and for their intended purposes. Do not mute hood alarms or circumvent any other safety devices provided on laboratory equipment. Inspect all equipment or apparatus for damage before use or addition of hazardous chemicals. Do not use damaged equipment.
Inspect personal protective equipment for integrity or proper functioning prior to each use. Malfunctioning laboratory equipment should be labeled or tagged "out of service" so others will not use prior to repairs being made.
Handle and store laboratory glassware with care. Do not use damaged glassware. Use extra care with Dewar flasks and other evacuated glass apparatus; shield or wrap them to contain chemicals or fragments should implosion occur.
Do not dispense more of a hazardous chemical than is needed for immediate use.
Permissible Exposure Limits (PEL): OSHA has provided a list of permissible exposure limits (PELs) for a number of chemicals. The Missouri University of Science and Technology Chemical Hygiene Plan includes a Hazardous Chemical and Select Carcinogen List. These list all chemicals for which OSHA has prescribed a PEL. Carcinogens are listed separately because special handling is required for these chemicals.
- Remove contaminated clothing and gloves before leaving the laboratory.
- Avoid direct contact with any chemical and underestimation of risk. Minimize all chemical exposures. Exposures should be minimized even for substances with no known significant hazard. Never smell, inhale or taste a hazardous chemical. Wash thoroughly with soap and water after handling any chemical.
- Drinking, eating, storing food, and the application of cosmetics is forbidden in laboratories where hazardous chemicals are used. Do not store food or drink in laboratory refrigerators or freezers.
- Never pipet by mouth. Use a pipet bulb or other mechanical pipet filling device.
- Confine long hair and loose clothing.
- Wear shoes at all times in the laboratory but do not wear clogs, sandals, perforated, or cloth shoes.
- Keep floors clean and dry. Keep all aisles, hallways, and stairs clear of all chemicals. Stairways and hallways should not be used as storage areas.
- Keep all work areas, especially work benches, clear of clutter and obstructions. All work surfaces should be cleaned regularly.
- Access to emergency equipment, utility controls, showers, eyewashes, fire extinguishers and exits should never be blocked.
- All wastes should be properly containerized and labeled according to Missouri S&T chemical waste manual requirements and EMS requirements.
2.2 When Not to Proceed Without Reviewing Safety Procedures (back to top)
Certain indicators, such as procedural changes, should cause an employee to stop and review safety procedures for the new procedure or change to existing procedure. Even if the task seems familiar, hazards may exist that are not fully recognized and should be evaluated. These indicators may include:
- A new procedure, process or test, even if very similar to older practices.
- A change or substitution of any chemical ingredient(s) in the procedure.
- A substantial change in the amount of chemicals used; review if increase is more than 200%.
- A failure of any equipment used in the procedure, especially safety equipment such as chemical hoods.
- Unexpected experimental results (pressure increase, increased reaction rates) or when the experimental result is different from the predicted. Review to determine if changes in safety practices should be made.
- Chemical odors, illness in lab staff that may be related to chemical exposure or other indicators of failed engineering safeguards.
Occurrence of any of these conditions should initiate a re-evaluation of safety precautions and impacts on safety equipment or safety procedures. Changes should be made if necessary and the procedure may continue with caution.
2.3 Protective Clothing & Safety Equipment (back to top)
Engineering and administrative controls should always be considered first when reducing or eliminating exposures to hazardous chemicals. These controls would include:
- Substitution of a less hazardous material
- Reduce the size of the experiment and quantity of hazardous chemicals
- Use less hazardous equipment or process (safety cans instead of glass)
- Isolation of operator or process
- Use chemical hoods or other type of local ventilation
The SDS's will list PPE recommended for the material, but this will be a worst case, so all listed equipment may not be required for use with the chemical. Your supervisor and other sections of this manual will help with the choice of correct PPE for specific tasks and type of hazard.
Body / Skin Protection
In order to protect the body, protective clothing will be required as appropriate. PPE should be selected on a task basis and checked prior to each use to ensure it is in good condition prior to use. Do not wear shorts or skirts in the laboratory. A lab coat should be worn over street clothes and regularly laundered. Closed toed shoes that cover the entire top of the foot should be worn in the lab; no sandals, open-toed, or perforated shoes are allowed in the lab. Long hair and loose clothing should be confined.
Some types of procedures or chemical use will require additional protective clothing. This clothing may include impermeable aprons and gloves or plastic coated coveralls, shoe covers, and arm sleeves. Always consider arm sleeves when using aprons. Never wear protective clothing outside the lab. Choice of protection depends on degree of protection required and which areas of the body may become contaminated. Rubberized aprons, plastic coated coveralls, shoe covers, and arm sleeves offer greater resistance to chemical permeation that lab coats and give more time to react (remove) if contaminated. Consider head covering as well if contamination is possible to protect scalp.
Chemical resistant gloves should be worn when the potential for contact with corrosive or toxic material and substances of unknown toxicity exists. Gloves are selected based on the material being handled, the hazard present with that material, and the suitability for operation being conducted. Check gloves for integrity before each use (even disposable). If using non-disposable gloves these should be washed prior to removal to prevent skin contamination and these gloves must be replaced periodically, depending on frequency of use and resistance to chemicals handled.
Protective garments are not all equally effective for every hazardous chemical. Always check the SDS for recommendations for glove selections, but some general criteria is found in the following table:
Glove Type Selection Guide
S=Superior, E=Excellent, G=Good, F=Fair, NR=Not Recommended
*Not recommended for Acetaldehyde, use butyl rubber.
|GLOVE TYPE SELECTION GUIDE|
|CHEMICAL FAMILY||BUTYL RUBBER||NEOPRENE||PVC (VINYL)||NITRILE||NATURAL LATEX|
|Nitro compounds (Nitrobenzene, Nitromethane)||G||NR||NR||NR||NR|
Source: Northeastern University's Chemical Hygiene Plan
Eye protection should be provided for all personnel and any visitors in all areas where chemicals are handled and a chemical splash hazard exists. Safety glasses, goggles, and goggles plus face shield should be worn in the laboratory based on physical state, operation, or level of toxicity of chemicals used. When used properly, safety glasses protect against solid materials (dusts and flying objects) but are less effective protecting against chemical splash to the face.
Goggles should be worn when bulk quantities of chemicals are used or when splashes to the face are possible. When highly reactive substances or large quantities of hazardous chemicals, corrosives, poisons, or hot chemicals are used a face shield with goggles should be used.
It is not necessary to require removal of contact lenses prior to entering eye hazardous environments. It is required that proper personal eye protection is to be worn by all persons including contact lens wearers in eye protection working areas.
See section 1.7
Laboratory Safety Equipment
The chemical hood is the primary means of controlling inhalation exposures. Hoods are designed to protect the operator by retaining vapors and gases released within them. This protection is accomplished by having a curtain of air (approximately 75-120 feet per minute) move constantly through the face (open sash) of the hood. Hoods can also be used to isolate apparatus for chemicals that may present physical hazards to employees. The closed sash serves as an effective barrier to fire, flying objects, chemical splashes or spattering, and small implosions and explosions. Small spills can also be effectively contained in a hood while chemicals are being dispensed, especially if trays are placed in the bottom of the hoods.
When using a chemical hood keep the following principles of safe operation in mind:
- Keep all chemicals and apparatus at least six inches inside the hood behind the sash.
- Hoods are not intended for storage and material in them should be kept to a minimum. Chemicals should not block vents or alter air flow patterns.
- Keep the sash at a minimum height (4 to 6 inches) when not manipulating chemicals or adjusting apparatus within the hood, but preferably closed completely.
- Make sure the sash opening is appropriate when working in a hood, typically 14-20 inches. This opening will ensure an adequate air velocity through the face of the hood.
- Do not allow objects such as paper to enter the exhaust ducts. This can clog ducts and adversely affect the proper operation.
The chemical manufacturer or supplier provides instructions for controlling inhalation exposures on the SDS or label of the hazardous material. If specific guidance is not available or inappropriate for the lab environment, contact your chemical hygiene officer or EHS.
Eyewashes and Safety Showers
If there is a possibility that chemicals may cause damage to the skin or eyes, an emergency supply of water must be available. Any laboratories using bulk quantities of hazardous chemicals should have access to eyewash stations and safety showers. This safety equipment is only useful if it is accessible, therefore:
- Keep all passageways to the eyewash and shower clear of any obstacle (even a temporary one such as a chemical cart.)
- Eyewashes should be checked routinely to be certain that clean water flows through it.
- Showers should be checked routinely to assure that access is not restricted and the start chain is within reach.
- Eyewashes and showers are inspected annually by EHS. Lab personnel are encouraged to check eyewashes weekly and safety showers at least quarterly.
Fire Safety Equipment
A fire extinguisher must be available within 50 feet of each laboratory and easily accessible to personnel. Other equipment may include fire blankets or automatic extinguishing systems.
2.4 Chemical Procurement, Distribution & Storage (back to top)
Information on the proper handling, storage and disposal of a new substance should be known to those who will handle the material. It is the responsibility of the supervisor to ensure that the laboratory facility is adequate for the material and that those who will handle the material have received proper training. Only the quantity that can be immediately used should be ordered. Large amounts of material should not be stored in the laboratories.
All chemicals ordered for use on the Missouri S&T campus must be intercepted by an authorized materials receiver (AMR) and bar-coded prior to delivery to researcher. Chemical information is entered into the CHEMTRACK system to inventory the material and each chemical receives a unique barcode number. No material should be received or stored without being bar-coded and entered into CHEMTRACK.
Chemical Storage in the Laboratory
Carefully read the label before storing a hazardous chemical. The SDS will provide any special storage information as well as information on incompatibilities. Do not store unsegregated chemicals in alphabetical order. Do not store incompatible chemicals in close proximity to each other.
Chemicals should be segregated into the following hazard classes for safe storage:
- Corrosives-acids, bases
- Highly Reactive
- Extreme Toxic/Regulated Material
- Low Hazard
One problem with this type of storage plan is the actual identification of the hazards themselves. First determine the priorities then choose a storage location. Look at flammability first and how corrosive the item is next. There will always be some material that does not fit neatly into one category or another, but after carefully considering the hazards associated with the material, most situations can be resolved and appropriate storage determined.
Use approved storage containers and safety cans for flammable liquids. It is preferred and advised to store flammable chemicals in a National Fire Protection Association (NFPA) approved flammable liquid storage cabinet. Flammable chemicals requiring refrigeration must be stored only in refrigerators and freezers designed for flammable storage.
A good place to store hazardous chemicals is in a vented cabinet under the hood. Chemicals of different chemical classes can be segregated by placing them in trays. Do not store chemicals on bench tops or in hoods. Store liquids (especially corrosives or solvents) below eye level. Use secondary containers for especially hazardous chemicals.
Conduct periodic inventory checks of chemicals stored in the lab and dispose of old or unwanted chemicals promptly in accordance with the Chemical Waste program or the Chemical Redistribution program.
Chemical Storage-Chemical Stability
Stability refers to the susceptibility of a chemical to dangerous decomposition. The label and SDS will give guidance on the chemical stability.
Peroxide Formers- Ethers, liquid paraffins, and olefins form peroxides on exposure to air and light. Certain peroxides are extremely sensitive to shock, sparks, or other forms of accidental ignition (even more sensitive than primary explosives such as TNT). If these chemicals are packaged in an air atmosphere, peroxides can form even though the containers have not been opened. These types of materials should be dated when received and when opened. Protocol for handling these chemicals is provided in Appendix A.
Chemical Storage-Incompatible Chemicals
A severe or toxic reaction can take place when certain hazardous chemicals are mixed or stored with other chemicals. The label and SDS will contain information on incompatibilities.
The following table contains examples of incompatible chemicals:
Keep Out of Contact With:
Chromic Acid, nitric acid hydroxyl compounds, ethylene, glycol, perchloric acid, peroxides, permanganates
Concentrated nitric acid and sulfuric acid mixtures
Chlorine, bromine, copper, fluorine, silver, mercury
Water, carbon tetrachloride or other chlorinated hydrocarbons, carbon dioxide, the halogens
Mercury, chlorine, calcium hypochlorite, iodine, bromine, hydrofluoric acid
Acids, metal powders, flammable liquids, chlorates, nitrites, sulfur, finely divided organic or combustible materials
Nitric acid, hydrogen peroxide
Any reducing agent
Same as chlorine
Calcium hypochlorite, all oxidizing agents.
Ammonium salts, acids, metal powders, sulfur, finely divided organic or combustible materials
Acetic acid, naphthalene, camphor, glycerin, turpentine, alcohol, flammable liquids in general
Ammonia, acetylene, butadiene, butane, methane, propane (or other petroleum gases), hydrogen, sodium carbide, turpentine, benzene, finely divided metals
Ammonia, methane, phosphine, hydrogen sulfide
Acetylene, hydrogen peroxide
Acids, organic or inorganic
Ammonium nitrate, chromic acid, hydrogen peroxide, nitric acid, sodium peroxide, halogens
Fluorine, chlorine, bromine, chromic acid, sodium peroxide
Nitric acid, alkali
Ammonia, aqueous or anhydrous
Copper, chromium, iron, most metals or their salts, alcohols, acetone, organic materials, aniline, nitromethane, flammable liquids, oxidizing gases
Fuming nitric acid, oxidizing gases, acetylene, ammonia (aqueous or anhydrous), hydrogen
Acids, activated carbon
Acetylene, ammonia (aqueous or anhydrous), hydrogen
Acetylene, fulminic acid, ammonia
Nitric Acid (concentrated)
Acetic acid, aniline, chromic acid, hydrocyanic acid, hydrogen sulfide, flammable liquids, flammable gases
Inorganic bases, amines
Oils, grease, hydrogen; flammable liquids, solids, or gases
Acetic anhydride, bismuth and its alloys, alcohol, paper, wood
Acids (organic or mineral), avoid friction, store cold
Air, oxygen, alkalies, reducing agents
Carbon tetrachloride, carbon dioxide, water
Sulfuric and other acids
Glycerin, ethylene glycol, benzaldehyde, sulfuric acid
Acetylene, oxalic acid, tartaric acid, ammonium compounds
Carbon tetrachloride, carbon dioxide, water
Ammonium nitrate and other ammonium salts
Ethyl or methyl alcohol, glacial acetic acid, acetic anhydride, benzaldehyde, carbon disulfide, glycerin, ethylene glycol, ethyl acetate, methyl acetate, furfural
Potassium chlorate, potassium perchlorate, potassium permanganate (or compounds with similar light metals, such as sodium, lithium, etc.)
(From Manufacturing Chemists' Association, Guide for Safety in the Chemical Laboratory, pp.215-217.)
2.5 Chemical Spills and Accidents (back to top)
Try to anticipate the types of spills that can occur in your laboratory and provide for the proper spill equipment to respond to a minor spill. The SDS for the material will contain spill response information. Only attempt to respond to small spills that you can safely respond to and leave larger spills to knowledgeable and experienced personnel. Spill response procedures should be posted in the lab and are available in the EHS manual found online. (Link to Haz. Waste Mgt. Manual).
If a spill is too large for you to handle, call for assistance immediately: Campus Police at extension 911 and Environmental Health & Safety 573-341-4305.
Cleaning Up Chemical Spills
If you are cleaning up a small spill, make sure you are aware of the hazards associated with the materials spilled, have adequate ventilation (open window, chemical hood on) and proper PPE (minimum-gloves, goggles, and lab coat). Consider all residual chemical and cleanup materials as hazardous waste. Place these materials in a sealed container (plastic bags) and store in a chemical hood. Contact EHS for disposal instructions.
Minor Chemical Spill
- Alert people in immediate area of spill.
- Increase ventilation in area of spill (open window, turn on hood).
- Wear protective equipment, including safety goggles, gloves and long-sleeve lab coat.
- Avoid breathing vapors from spill.
- Use appropriate kit to neutralize and absorb inorganic acids and bases. Collect residue, place in a container, and dispose of container as hazardous waste.
- For other chemicals, use appropriate kit or absorb spill with vermiculite, dry sand, diatomaceous earth or paper towels. Collect residue, place in container, and dispose of as chemical waste.
- Clean spill area.
Major Chemical Spill
- Call 911
- Attend to injured or contaminated persons and remove from exposure, if possible without injuring yourself.
- Alert people in the lab to evacuate.
- If spilled material is flammable, turn off ignition and heat sources. Place other device (plastic bag) over spilled material to keep substance from volatilizing.
- Close doors to affected area.
- Have a person with knowledge of the incident and laboratory available to answer questions from responding emergency personnel.
EHS has a mercury vacuum and should be called for all large mercury spills. Kits are available commercially for small spills that may occur in the lab. Small droplets in inaccessible areas may be covered with powdered zinc and place residue in a labeled container and dispose of as hazardous chemical waste.
Alkali Metal Spills
Smother with powdered graphite, sodium carbonate, calcium carbonate or "Met-L-X".
Smother with wet sand or wet "noncombustible" absorbent.
Neutralize with soda ash or lime (or absorb with special HF spill pillow). Absorb with an inert absorbent material.
2.6 Personal Contamination and Injury (back to top)
The following information is provided as a general guide for handling chemical exposure and is not intended to be comprehensive. Personnel working with hazardous materials should read the SDS for that material and become familiar with the hazards and the treatments needed should an exposure occur.
- Know the location of the nearest safety shower and eye wash station.
- Report all incidents and injuries to your supervisor.
- If an individual is contaminated or exposed to a hazardous material in your laboratory, do what is necessary to protect their life and health as well as your own. Determine what the individual was exposed to and consult the SDS for first aid information.
- Do not move an injured person unless they are in further danger (inhalation or skin exposure).
- A blanket should be used immediately to protect the victim from shock and exposure.
- Get medical attention promptly by dialing University Police at 911.
Chemical Spills on the Body
- Quickly remove all contaminated clothing and footwear.
- Immediately flood the affected area in cold water for at least 15 minutes. Remove jewelry to facilitate removal of any residual material.
- Wash off chemical with water only. Do Not Use neutralizing chemicals, unguents, creams, lotions, or salves unless the spill involves Hydrofluoric Acid.
- Get medical attention promptly.
It should be noted that some chemicals (phenol, aniline) are rapidly adsorbed through the skin. If a large enough area is contaminated, an adverse health effect may occur immediately to several hours after the initial exposure depending on the chemical. If more than 9 square inches of skin area has been exposed to a hazardous chemical, seek medical attention after washing the material off the skin. If the material involved is hydrofluoric acid (HF), seek immediate medical attention. Provide the chemical name to the physician. (See appendix B)
Chemical Splash in the Eye
- Irrigate the eyeball and inner surface of the eyelid with plenty of cool water for at least 15 minutes. Use eyewash or other water source. Forcibly hold eyelids open to ensure effective wash.
- Check for and remove contact lenses.
- Get medical attention promptly.
Ingestion of Hazardous Chemical
- Identify the chemical ingested.
- Call for an ambulance by dialing 911.
- Cover the injured person to prevent shock.
- Provide the ambulance crew and physician with the chemical name and any other relevant information. If possible, send the container, SDS or the label with the victim.
Inhalation of Smoke, Vapors and Fumes
- Anyone overcome with smoke or chemical vapors or fumes should be removed to uncontaminated air and treated for shock.
- Do not enter the area if you expect that a life threatening condition still exists-oxygen depletion, explosive vapors or highly toxic gases (cyanide gas, hydrogen sulfide, nitrogen oxides, carbon monoxide).
- If CPR certified, follow standard CPR protocols.
- Get medical attention promptly.
Burning Chemicals on Clothing
- Extinguish burning clothing by using the drop-and-roll technique or by dousing with cold water, or use an emergency shower if it is immediately available.
- Remove contaminated clothing: however, avoid further damage to the burned area. If possible, send clothing with the victim.
- Remove heat with cool water or ice packs until tissue around burn feels normal to the touch.
- Cover injured person to prevent shock.
- Get medical attention promptly.
Actions to be Avoided During Emergencies
There are some actions which must not be taken when handling emergencies. These include:
- Do not force any liquids into the mouth of an unconscious person.
- Do not handle emergencies alone, especially without notifying someone that the accident has occurred.
- Do not linger at the accident scene if you are not one of the emergency responders or the point of contact for the area.
2.7 Fire and Fire Related Emergencies (back to top)
Personnel should plan ahead and know the locations of fire extinguishers, alarm pull stations and emergency exits. If you discover a fire or fire-related emergency, immediately follow these procedures:
- Notify the University Police 911.
- Activate the building alarm (fire pull station). If not available or operational, verbally notify people in the building.
- Isolate the area by closing windows and doors and evacuate the building.
- Shut down equipment in the immediate area, if possible.
Use a portable fire extinguisher to:
- assist oneself to evacuate;
- assist another to evacuate; and
- control a small fire, if possible.
- Provide the fire/police teams with the details of the problem upon their arrival. Special hazard information you might know is essential for the safety of the emergency responders.
If the fire alarms are ringing in you building:
- Shut down equipment if possible and evacuate the building and stay out until notified to return.
- Move up wind from the building and stay clear of streets, driveways, sidewalks, and other access ways to the building.
- If you are a supervisor, try to account for your employees, keep them together and report any missing persons to the emergency personnel at the scene.
2.8 Chemical Waste Disposal Program (back to top)
Laboratory chemical waste must be disposed of in accordance with local, state, federal, and Missouri S&T requirements. These waste management practices are designed to ensure maintenance of a safe and healthful environment for laboratory employees and the surrounding community without adversely affecting the environment. This is accomplished through regular removal of chemical waste and disposal of these wastes in compliance with all regulations and policies. Specific guidance on how to identify, handle, and request disposal pickup can be found in the Hazardous Waste, Forms and Instructions section of the Waste Management Program available at the EHS website.
All waste must be tagged with chemical waste tags (available from EHS). These tags should be filled out and dated with the accumulation start date, the generators name, location of waste and contents of waste container. Missouri S&T policy limits the storage time for waste in laboratories and other areas to a maximum of 90 days. Waste containers must be closed unless waste is being added or removed and stored properly until pickup.
Section 3- Information for Work with Chemicals of Specific Hazard Class
3.1 Flammable Liquids (back to top)
Flammable liquids are among the most common of the hazardous materials found in laboratories. They are usually highly volatile (have high vapor pressures at room temperature) and their vapors, mixed with air at the appropriate ratio, can ignite and burn. By definition, the lowest temperature at which they can form an ignitable vapor/air mixture (flash point) is less than 37.8°C and for several common laboratory solvents (ether, acetone, toluene, acetaldehyde) the flash point is well below that. As with all solvents, their vapor pressure increases with temperature. Therefore, as temperatures increase the material becomes more hazardous.
For a fire to occur, three conditions must exist simultaneously:
1. The concentration of the vapor must be between the upper and lower flammable limits of the substance (the right fuel / air mix);
2. an oxidizing atmosphere, usually air, must be available; and
3. a source of ignition must be present.
Removal of any of these three conditions will prevent the start of a fire. Flammable liquids may form flammable mixtures in either open or closed containers or spaces (such as refrigerators), when leaks or spills occur in the laboratory, and when heated.
Strategies for preventing ignition of flammable vapors include removing all sources of ignition or maintaining the concentration of flammable vapors below the lower flammability limit by using local exhaust ventilation such as a hood. Removing sources of ignition is more difficult because of the numerous sources available in laboratories such as open flames, hot surfaces, operation of electrical equipment, and static electricity.
The concentrated vapors of flammable liquids may be heavier than air and can travel away from a source for some distance (across lab, into hallways, down elevator shafts or stairways). If the vapors reach a source of ignition, a flame can result that may flash back to the source of the vapor.
The danger of fire and explosion presented by flammable liquids can usually be eliminated or minimized by strict observance of safe handling, dispensing, and storing procedures.
Special Handling Procedures
While working with flammable liquids you should wear gloves, protective glasses, and long sleeved lab coats. Wear goggles if dispensing solvents or performing an operation which could result in a splash to the face.
Large quantities of flammable liquids should be handled in a chemical hood or under some type of local exhaust ventilation. Five-gallon containers must be dispensed into smaller containers in a hood or under local exhaust ventilation. Dispense flammable substances into metal or plastic containers or safety cans, avoid glass containers.
Make sure that metal surfaces or containers through which flammable substances are flowing are properly grounded, discharging static electricity. Free flowing liquids generate static electricity, which can produce a spark and ignite the solvent. Large quantities of flammable liquids must be handled in areas free of ignition sources (including spark emitting motors and equipment) using non-sparking tools. Remember that vapors are heavier than air and can travel to a distant source of ignition.
Do not heat flammable substances by using an open flame. Use any of the following instead: steam baths, water baths, oil baths, heating mantles or hot air baths.
Store flammable substances away from ignition sources in NFPA approved flammable storage cabinets. If no flammable storage cabinet is available, store these substances in a cabinet under the hood or bench. Five-gallon containers should only be stored in a flammable storage cabinet or under a hood. Glass containers used for flammable liquids must not exceed 4 liters in capacity. Keep flammable liquids inside the hood for a short period of time and do not store long term. Chemical storage in hoods reduces hood performance by obstructing air flow.
Oxidizing and corrosive materials should not be stored in close proximity to flammable liquids. Do not store or chill flammable liquids in domestic refrigerators and freezers but in units specifically designed for this purpose. If flammable liquids are placed in ovens, make sure they are properly designed for flammable liquids with no internal ignition source and/or vented mechanically.
3.2 Highly Reactive Chemicals & Energy Oxidizers (back to top)
Highly reactive chemicals include those which are inherently unstable and susceptible to rapid decomposition as well as chemicals which, under specific conditions, can react alone or with other substances in a violent uncontrolled manner, liberating heat, toxic gases, or leading to an explosion. Reaction rates almost always increase dramatically with temperature increases. If the heat evolved from a reaction is not dissipated, the reaction can accelerate out of control and possibly result in injuries or costly accidents.
Air, light, heat, mechanical shock (when struck, vibrated or otherwise agitated), water, and certain catalysts can cause decomposition of some highly reactive chemicals, and initiate an explosive reaction. Hydrogen and chlorine react explosively in the presence of light. Alkali metals, such as sodium, potassium and lithium, react violently with water giving off hydrogen gas. Examples of shock sensitive materials include acetylides, azides, organic nitrates, nitro compounds, and many peroxides.
Organic peroxides are a special class of compounds that have unusual stability problems, making them among the most hazardous substances normally handled in the laboratories. As a class, organic peroxides are low powered explosives. Organic peroxides are extremely sensitive to light, heat, shock, sparks, and other forms of accidental ignition; as well as to strong oxidizing and reducing materials. All organic peroxides are highly flammable.
Peroxide formers can form peroxides during storage and especially after exposure to the air (once opened). Peroxide forming substances include: aldehydes, ethers (especially cyclic ether), compounds containing benzylic hydrogen atoms, compounds containing the allylic structure (including most alkenes), vinyl and vinylidine compounds.
Examples of shock sensitive chemicals, high-energy oxidizers and substances, which can form explosive peroxides, are listed at the end of this section. The Missouri S&T peroxide testing procedure/policy is found in Appendix A.
Special Handling Procedures
Before working with a highly reactive material or high-energy oxidizer, review available reference literature to obtain specific safety information. The proposed reactions should be discussed with your supervisor. Always minimize the amount of material involved in the experiment. Scale-ups should be handled with great care, giving consideration to the reaction, vessel size and cooling, heating, stirring, and equilibration rates.
Excessive amounts of highly reactive compounds should not be purchased, synthesized, or stored in the laboratories. The key to safely handling reactive chemicals is to keep them isolated from the substances that initiate their violent reactions. Unused peroxides should not be returned to the original container.
Do not work alone. All operations where highly reactive and explosive chemicals are used should be performed during normal working hours or when other employees are available either in the same lab or in the immediate area. Perform all manipulations in a chemical hood. Consider the adequacy of the hood including size and required equipment, the ability to close the sash and the sash composition. Make sure the equipment is properly secured. Reaction vessels should be supported from beneath with tripods or lab jacks. Use shields or guards, which are clamped or secured.
Handle shock sensitive substances gently, avoid friction, grinding, and all forms of impact. Glass containers that have screw-cap lids or glass stoppers should not be used. Polyethylene bottles that have screw-cap lids may be used. Handle water-sensitive compounds away from water sources. Light-sensitive chemicals should be used in light-tight containers. Handle highly reactive chemicals away from direct light, open flames, and other sources of heat. Oxidizing agents should only be heated with fiberglass heating mantles or sand baths.
High-energy oxidizers, such as perchloric acid, should only be handled in a wash down hood if the oxidizer will volatilize and potentially condense in the ventilation system. Inorganic oxidizers such as perchloric acid can react violently with most organic materials.
When working with highly reactive compounds and high-energy oxidizers, always wear the following personal protection equipment: lab coats, gloves, and protective glasses/goggles. During the reaction, a face shield long enough to give throat protection should be worn.
Labels on peroxide forming substances should contain the date the container was received, first opened and subsequently tested. They should be visually checked for the presence of peroxides before using. Never use a metal spatula with peroxides. Contamination by metals can lead to explosive decompositions.
See Appendix A for protocol on handling peroxide formers.
Store reactive chemicals and high-energy oxidizers in closed cabinets segregated from the materials with which they react, and if possible in secondary containers at the lowest possible temperature.
List of Shock Sensitive Chemicals
Shock sensitive refers to the susceptibility of the chemical to rapidly decompose or explode when struck, vibrated or otherwise agitated. The following are examples of materials, which can be shock sensitive:
|Acetylides of heavy metals||Dipicryl sulfone||Sodium dinitro-orthocresolate|
|Aluminum ophrite explosive||Dipicrylamine||Sodium nitrate-potassium|
|Amatol||Erythritol tetranitrate||Sodium picramate|
|Ammonal||Fulminate of mercury||Styphnic acid|
|Ammonium nitrate||Fulminate of silver||Tetranitrocarbazole|
|Ammonium perchlorate||Fulminating gold||Tetrazene|
|Ammonium picrate||Fulminating mercury||Tetrytol|
|Ammonium salt lattice||Fulminating platinum||Trimethylolethand|
|Butyl tetryl||Fulminating silver||Trimonite|
|Calcium nitrate||Gelatinized nitrocellulose||Trinitroanisole|
|Cyanuric triazide||Guanyl nitrosamino||Trinitrobenzoic acid|
|Dinitroethyleneurea||Heavy metal azides||Trinitronaphtalene|
|Dinitrotoluene||Sodium amatol||Urea nitrate|
List of Peroxide Formers
For the complete list of peroxide formers EHS requires to be tested see #11 Category Selection in Chemtrack.
3.3 Compressed Gases (back to top)
Compressed gases are unique in that they represent both a physical and a potential chemical hazard (depending on the particular gas). Gases contained in cylinders may be from any of the hazard classes described in this section (flammable, reactive, corrosive, or toxic). Because of their physical state (gaseous), concentrations in the laboratory can increase instantaneously if leaks develop at the regulator or piping systems, creating the potential for a toxic chemical exposure or a fire/explosion hazard. Often there is little or no indication that leaks have or are occurring. Finally, the large amount of potential energy resulting from compression of the gas makes a compressed gas cylinder a potential rocket or fragmentation bomb if the tank or valve is physically broken.
Special Handling Procedures
The contents of any compressed gas cylinder should be clearly identified. No cylinder should be accepted for use that does not legibly identify its contents by name. Color coding is not a reliable means of identification and labels on caps have no value as caps are interchangeable.
Carefully read the SDS before using or storing compressed gas. The SDS will provide any special hazard information.
Transport gas cylinders in carts one or two at a time only while they are secured and capped. All gas cylinders should be capped and secured when stored. Use suitable racks, straps, chains or stands to support cylinders. All cylinders, full or empty, must be restrained and kept away from heat sources. Store as few cylinders as possible in your laboratory.
Use only Compressed Gas Association standard combinations of valves and fittings for compressed gas installations.Always use the correct pressure regulator. Do not use a regulator adaptor.
All gas lines leading from a compressed gas supply should be clearly labeled identifying the gas and the laboratory served.
Place gas cylinders in such a way that the cylinder valve is accessible at all times. The main cylinder valve should be closed as soon as the gas flow is no longer needed. Do not store gas cylinders with pressure on the regulator. Use the wrenches or other tools provided by the cylinder supplier to open a valve if available. In no case should pliers be used to open a cylinder valve.
Use Sherlock or Radnor to detect leaks. Leak test the regulator, piping system and other couplings after performing maintenance or modifications, which could affect the integrity of the system.
Oil or grease on the high pressure side of an oxygen cylinder can cause an explosion. Do not lubricate an oxygen regulator or use a fuel/gas regulator on an oxygen cylinder.
Never bleed a cylinder completely empty. Leave a slight pressure to keep contaminants out (172 kPa or 25 psi). Empty cylinders should not be refilled in the laboratories unless equipped to prevent overfilling.
All gas cylinders should be clearly marked with appropriate tags indicating whether they are in use, full, or empty. Empty and full cylinders should not be stored in the same place.
Cylinders of toxic, flammable or reactive gases should be purchased in the smallest quantity possible and stored/used in a fume hood or under local exhaust ventilation. If at all possible, avoid the purchase of lecture bottles. These cylinders are not returnable and it is extremely difficult and costly to dispose of them. Use the smallest returnable sized cylinder.
Wear safety goggles when handling compressed gases, which are irritants, corrosive or toxic.
Wear appropriate personal protective equipment when handling cyrogenics.
Special Precautions for Hydrogen
Hydrogen gas has several unique properties, which make it potentially dangerous to work with. It has an extremely wide flammability range (LEL 4%, UEL 74.5%) making it easier to ignite than most other flammable gases. Unlike most other gases, hydrogen's temperature increases during expansion. If a cylinder valve is opened too quickly, the static charge generated by the escaping gas may cause it to ignite. Hydrogen burns with an invisible flame. Caution should therefore be exercised when approaching a suspected hydrogen flame. A piece of paper can be used to tell if the hydrogen is burning. Hydrogen embrittlement can weaken carbon steel, therefore cast iron pipes and fittings should not be used. Those precautions associated with other flammable substances also apply to Hydrogen (see Section 3.1).
3.4 Corrosive Chemicals (back to top)
The major classes of corrosive chemicals are strong acids and bases, dehydrating agents, and oxidizing agents. These chemicals can erode the skin and the respiratory epithelium and are particularly damaging to the eyes. Inhalation of vapors or mists of these substances can cause severe bronchial irritation. If your skin is exposed to a corrosive, flush the exposed area with water for at least fifteen minutes. Then seek medical treatment.
Strong acids. All concentrated acids can damage the skin and eyes and their burns are very painful. Nitric, chromic, and hydrofluoric acids are especially damaging because of the types of burns they inflict. Seek immediate medical treatment if you have been contaminated with these materials (particularly hydrofluoric acid - Read Appendix B before working with HF).
Strong alkalis. The common strong bases used in the labs are potassium hydroxide, sodium hydroxide, and ammonia. Burns from these materials are often less painful than acids. However, damage may be more severe than acid burns because the injured person, feeling little pain, often does not take immediate action and the material is allowed to penetrate into the tissue. Ammonia is a severe bronchial irritant and should always be used in a well-ventilated area, if possible in a hood.
Dehydrating agents. This group of chemicals includes concentrated sulfuric acid, sodium hydroxide, phosphorus pentoxide, and calcium oxide. Because much heat is evolved on mixing these substances with water, mixing should always be done by adding the agent to water, and not the reverse, to avoid violent reaction and spattering. Because of their affinity for water, these substances cause severe burns on contact with skin. Affected areas should be washed promptly with large volumes of water.
Oxidizing agents. In addition to their corrosive properties, powerful oxidizing agents such as perchloric and chromic acids (sometimes used as cleaning solutions), present fire and explosion hazards on contact with organic compounds and other oxidizable substances. The hazards associated with the use of perchloric acid are especially severe. It should be handled only after thorough familiarization with recommended operating procedures (see section 3.2 on Highly Reactive Chemicals & Energy Oxidizers).
Special Handling Procedures
Corrosive chemicals should be used in the chemical fume hood, or over plastic trays when handled in bulk quantities (> 1 liter) and when dispensing.
When working with bulk quantities of corrosives, wear gloves, face shields, laboratory coats, and rubber aprons.
If you are handling bulk quantities of corrosive material or there is a potential for splashing, an eyewash should be immediately available and a shower close by. Spill materials - absorbent pillows, neutral absorbent materials or neutralizing materials (all commercially available) should be available in the laboratory.
Store corrosives in cabinets designed for corrosive material storage, under the hood or on low shelves, preferably in the impervious trays to separate them physically from other groups of chemicals. Vapors from corrosive materials can corrode unprotected metal and weaken storage shelves resulting in collapse and spillage. Keep containers not in use in storage areas and off bench tops.
If it is necessary to move bulk quantities from one laboratory to another or from the stockroom, use a safety carrier (rubber bucket for secondary containment and protection of the container).
3.5 Chemicals of Acute and High Toxicity (back to top)
Substances that are considered to possess the characteristic of high acute toxicity can cause damage after a single or short-term exposure. The immediate toxic effects range from irritation to illness and death. Hydrogen cyanide, phosgene, nitrogen dioxide and hydrofluoric acid (HF) (See Appendix B for information on HF) are examples of substances with high acute toxicity. The lethal oral dose for an average human adult for highly toxic substances range from one ounce to a few drops. Oral LD50 data for the rat or mouse is listed in the substance's SDS.
Substances that possess the characteristic of high chronic toxicity cause damage after repeated exposure or over long periods of time. Health effects may not become evident until after a latency period of twenty to thirty years. Substances that are of high chronic toxicity may be toxic to specific organ systems -hepatotoxins, nephrotoxins, neurotoxins, toxic agents to the hematopoietic system and pulmonary tissue or carcinogens, reproductive toxins, mutagens, tereatogens or sensitizers. Definitions of each of these categories and examples of substances falling into each of these different categories are found in Section 4 of this plan.
Special Handling Procedures
Avoid or minimize contact with these chemicals by any route of exposure. Always wear gloves and a lab coat. Decontaminate gloves prior to removing them. Use material in a chemical hood or other appropriate containment device if the material is volatile or if the procedure generates aerosols.
Store volatile chemicals of high acute or chronic toxicity in the cabinet under the hood or other vented area. Volatile chemicals should be stored in unbreakable primary or secondary containers or placed in chemically resistant trays. Nonvolatile chemicals should be stored in cabinets or in drawers. Do not store these chemicals on open shelves or counters.
Decontaminate working surfaces appropriately after completing procedures. Volatile chemicals should be transported between laboratories in durable outer containers. Vacuum pumps used in procedures should be protected from contamination with scrubbers or filters.
If one or more of these substances are used in large quantities, on a regular basis (3 or more separate handling sessions per week), or for long periods of time (4-6 hours) a qualitative and potentially quantitative exposure assessment should be performed. Lab personnel of childbearing age should be informed of any known male and female reproductive toxins used in the laboratory. An employee who is pregnant, or planning to become pregnant, and who is working with potential reproductive toxins that might affect the fetus, should contact the Chemical Hygiene Officer to evaluate their potential exposure and if necessary adjust work practices to minimize the risk.
3.6 Protocols for Dealing with Carcinogens, Mutagens and Teratogens (back to top)
This section establishes supplemental work procedures to control the handling of substances that are known to exhibit unusual acute or long-term chronic health hazards (carcinogens, reproductive toxins and highly acutely toxic substances).
This set of procedures applies to chemical carcinogens listed and regulated by the Department of Labor, OSHA, and of human carcinogens listed by the International Agency for Research on Cancer (IARC) and the National Toxicology Program (NTP).
Special authorization may be required before purchasing or using these substances, Appendix C lists the substances and/or procedures that require prior approval from the principal investigator and chemical hygiene officer for the research protocol before beginning work.
Special Handling Procedures
Use of a chemical hood or other appropriate containment device (glove box) is required when using these chemicals. Access to all of these chemicals should be restricted.
All procedures with these chemicals should be performed in designated areas. Other employees working in the same area should be informed of the hazards associated with these substances and the precautions necessary for preventing exposures. All designated areas should be posted with a sign, which reads:
DESIGNATED AREA FOR HANDLING THE FOLLOWING
SUBSTANCES WITH HIGH ACUTE OR CHRONIC TOXICITY:
[list of substances-identify the hazard]
[Example: Benzene - carcinogen]
AUTHORIZED PERSONNEL ONLY
Vacuum pumps used in procedures should be protected from contamination with scrubbers or filters. Analytical instruments or other laboratory equipment generating vapors and/or aerosols during their operation, should be locally vented in a chemical hood.
Skin surfaces which might be exposed to these substances during routine operations or foreseeable accidents should be covered with appropriate protective clothing. Gloves should be worn whenever transferring or handling these substances. Consider using full body protection (disposable coveralls) if the potential for extensive personal contamination exists.
All protective equipment should be removed when leaving the designated area and decontaminated (washed) or, if disposable, placed in a plastic bag and secured. Call EHS about disposal instructions. Skin surfaces - hands, forearms, face and neck - should be washed immediately. Work surfaces should be covered with an easily decontaminated surface such as stainless steel or protected with plastic trays or plastic backed paper to prevent contamination. Materials that will be disposed of should be placed in plastic bags and secured.
Chemical wastes from procedures using these substances should be placed in containers and disposed of according to Missouri S&T Chemical Waste Disposal policies. Waste should be maintained in the designated work area until it is picked up. If it is possible to safely chemically treat all toxic substances to nontoxic materials during or at the end of the procedure, this should be written in a standard operating procedure as part of the research and performed as such. Normal laboratory work should not be conducted in the designated area until it has been decontaminated or determined to be acceptable by the principal investigator or EHS.
3.7 Protocols for Dealing with Nanomaterials (back to top)
For information on nanomaterials please see Appendix D.
4.1 Chemical Toxicology Overview (back to top)
Toxicology - study of the nature and action of poisons.
Toxicity - ability of a chemical substance or compound to produce injury once it reaches a susceptible site in, or on, the body.
Hazard potential - probability that injury will occur after consideration of the conditions under which the substance is used.
Dose-Response Relationships - The potential toxicity (harmful action) inherent in a substance is exhibited only when that substance comes in contact with a living biological system. The potential toxic effect increases as the exposure increases. All chemicals will exhibit a toxic effect given a large enough dose. The toxic potency of a chemical is thus ultimately defined by the dose (amount) of the chemical that will produce a specific response in a specific biological system.
Routes of Entry into the Body - There are three main routes by which hazardous chemicals enter the body:
- Absorption through the respiratory tract via inhalation.
- Absorption through the skin via dermal contact.
- Absorption through the digestive tract via ingestion. (Ingestion can occur through eating or smoking with contaminated hands or in contaminated work areas.)
Most exposure standards, such as the Threshold Limit Values (TLV's) and Permissible Exposure Limits (PEL's), are based on the inhalation route of exposure. These limits are normally expressed in terms of either parts per million (ppm) or milligrams per cubic meter (mg/m3) concentration in air. If a significant route of exposure for a substance is through skin contact, the SDS, PEL and/or TLV will have a "skin" notation. Examples of substances where skin absorption may be a significant factor include: pesticides, carbon disulfide, carbon tetrachloride, dioxane, mercury, thallium compounds, xylene and hydrogen cyanide.
Types of Effects
Acute poisoningis characterized by sudden and severe exposure and rapid absorption of the substance. Normally, a single large exposure is involved. Adverse health effects are often reversible. Examples: carbon monoxide or cyanide poisoning.
Chronic poisoning is characterized by prolonged or repeated exposures of a duration measured in days, months or years. Symptoms may not be immediately apparent. Health effects are often irreversible. Examples: lead or mercury poisoning.
Local effect refers to an adverse health effect that takes place at the point or area of contact. The site may be skin, mucous membranes, the respiratory tract, gastrointestinal system, eyes, etc. Absorption does not necessarily occur. Examples: strong acids or alkalis.
Systemic effect refers to an adverse health effect that takes place at a location distant from the body's initial point of contact and presupposes absorption has taken place. Examples: arsenic affects the blood, nervous system, liver, kidneys and skin; benzene affects bone marrow.
Cumulative poisons are characterized by materials that tend to build up in the body as a result of numerous chronic exposures. The effects are not seen until a critical body burden is reached. Example: heavy metals.
Substances in combination: When two or more hazardous materials are present at the same time, the resulting effect can be greater than the effect predicted based on the additive effect of the individual substances. This is called a synergistic or potentiating effect. Example: exposure to alcohol and chlorinated solvents; or smoking and asbestos.
Other Factors Affecting Toxicity
Rate of entry and route of exposure; that is, how fast is the toxic dose delivered and by what means.
Age can effect the capacity to repair tissue damage.
Previous exposure can lead to tolerance, increased sensitivity or make no difference.
State of health, physical condition and life style can affect the toxic response. Pre-existing disease can result in increased sensitivity.
Environmental factors such as temperature and pressure.
Host factors including genetic predisposition and the sex of the exposed individual.
Gas - substance in the gaseous state at room temperature and pressure.
Vapor - gaseous phase of a material which is ordinarily a solid or a liquid at room temperature and pressure.
When considering the toxicity of gases and vapors, the solubility of the substance is a key factor. Highly soluble materials, like ammonia, irritate the upper respiratory tract. On the other hand, relatively insoluble materials, like nitrogen dioxide, penetrate deep into the lung. Fat soluble materials, like pesticides, tend to have longer residence times in the body and be cumulative poisons.
Aerosol - solid or liquid particles of microscopic size dispersed in a gaseous medium. The toxic potential of an aerosol is only partially described by its airborne concentration. For a proper assessment of the toxic hazard, the size of the aerosol's particles must be determined. A particle's size will determine if a particle will be deposited within the respiratory system and the location of deposition. Particles above 10 micrometers tend to deposit in the nose and other areas of the upper respiratory tract. Below 10 micrometers particles enter and are deposited in the lung. Very small particles (<0.2 micrometers) are generally not deposited but exhaled.
Irritants are materials that cause inflammation of mucous membranes with which they come in contact. Inflammation of tissue results from exposure to concentrations far below those needed to cause corrosion. Examples include:
- Alkaline dusts and mists
- Arsenic trichloride
- Diethyl/dimethyl sulfate
- Hydrogen chloride
- Hydrogen fluoride
- Nitrogen dioxide
- Phosphorus chlorides
Irritants can also cause changes in the mechanics of respiration and lung function. Examples include:
- Acetic acid
- Formic acid
- Sulfur dioxide
- Sulfuric acid
Long term exposure to irritants can result in increased mucous secretions and chronic bronchitis.
A primary irritant exerts no systemic toxic action either because the products formed on the tissue of the respiratory tract are non-toxic or because the irritant action is far in excess of any systemic toxic action. Example: hydrogen chloride.
A secondary irritant's effect on mucous membranes is overshadowed by a systemic effect resulting from absorption. Examples include aromatic hydrocarbons and hydrogen sulfide.
Asphyxiants have the ability to deprive tissue of oxygen.
Simple asphyxiants are inert gases that displace oxygen. Examples include:
- Carbon dioxide
- Nitrous oxide
Chemical asphyxiants reduce the body's ability to absorb, transport, or utilize inhaled oxygen. They are often active at very low concentrations (a few ppm). Examples include carbon monoxide and cyanides.
Primary anesthetics have a depressant effect upon the central nervous system, particularly the brain. Examples include alcohols and halogenated hydrocarbons.
Hepatotoxic agents cause damage to the liver. Examples include carbon tetrachloride, nitrosamines, and tetrachloroethane.
Nephrotoxic agents damage the kidneys. Examples include halogenated hydrocarbons and uranium compounds.
Neurotoxic agents damage the nervous system. The nervous system is especially sensitive to organometallic compounds and certain sulfide compounds. Examples include:
- Carbon disulfide
- Methyl mercury
- Organic phosphorus insecticides
- Tetraethyl lead
- Trialkyl tin compounds
Some toxic agents act on the blood or hematopoietic system. The blood cells can be affected directly or the bone marrow (which produces the blood cells) can be damaged. Examples include:
There are toxic agents that produce damage of the pulmonary tissue (lungs) but not by immediate irritant action. Fibrotic changes can be caused by free silica and asbestos. Other dusts can cause a restrictive disease called pneumoconiosis. Examples include coal dust, cotton dust, and wood dust.
A carcinogen is an agent that can initiate or increase the proliferation of malignant neoplastic cells or the development of malignant or potentially malignant tumors. Known human carcinogens are listed in Appendix C.
A mutagen interferes with the proper replication of genetic material (chromosome strands) in exposed cells. If germ cells are involved, the effect may be inherited and become part of the genetic pool passed onto future generations.
A teratogen (embryotoxic or fetotoxic agent) is an agent, which interferes with normal embryonic development without causing a lethal effect to the fetus or damage to the mother. Effects are not inherited. Examples include lead and thalidomide.
A sensitizer is a chemical, which can cause an allergic reaction in normal tissue after repeated exposure to the chemical. The reaction may be as mild as a rash (allergic dermatitis) or as serious as anaphylactic shock. Examples include:
- Chromium compounds
- Chlorinated hydrocarbons
- Nickel compounds
- Poison ivy
- Toluene diisocyanate
4.2 Some Target Organ Effects (back to top)
The following is a categorization of target organ effects, which may occur from chemical exposure. Signs and symptoms of these effects and examples of chemicals which have been found to cause such effects are listed.
|Toxins||Target Organ Effects||Signs and Symptoms||Example Chemicals|
|Hepatotoxins||Cause liver damage||Jaundice, liver enlargement||Nitrosamines, chloroform, toluene, perchloro-ethylene, cresol, dimethylsulfate|
|Nephrotoxins||Cause kidney damage||Edema; proteinuria||Halogenated hydrocarbons, uranium, chloroform, mercury, dimethylsulfate|
|Neurotoxins||Affect the nervous system||Narcosis; behavior changes; decreased muscle coordination||Mercury, carbon disulfide, benzene, carbon tetrachloride, lead, mercury, nitrobenzene|
|Hematopoietic toxins||Decrease blood function||Cyanosis; loss of consicousness||Carbon monoxide, cyanides, nitro-benzene, aniline, arsenic, benzene, toluene|
|Pulmonary toxins||Irritate or damage the lungs||Cough; tightness in chest, shortness of breath||Silica, asbestos, ozone, hydrogen sulfide, chromium, nickel, alcohols|
|Reproductive Toxins||Affect the reproductive system||Birth defects; sterility||Lead, dibromodichloropropane|
|Skin Hazards||Affect the dermal layer of the body||Defatting of skin; rashes; irritation||Ketones, chlorinated compounds, alcohols, nickel, phenol, tri-chloroethylene|
|Eye hazards||Affect the eye or vision||Conjunctivitis, corneal damage||Organic solvents, acids, cresol, quinone, hydroquinone, benzol, chloride, butyl alcohol, bases|
4.3 Occupational Health Standards (back to top)
TLV: The threshold limit value is a recommended occupational exposure guideline published by the American Conference of Governmental Industrial Hygienists. TLV's are expressed as parts of vapor or gas per million parts of air by volume (ppm) or as approximate milligrams of particulate per cubic meter or air (mg/M3). The TLV is the average concentration of a chemical that most people can be exposed to for a working lifetime with no ill effects. The TLV is an advisory guideline. If applicable, a ceiling concentration (C), which should not be exceeded, or a skin absorption notation (S) will be indicated with the TLV.
PEL: The permissible exposure limit is a legal standard issued by OSHA. Unless specified, the PEL is a time weighted average (TWA).
TWA: Most exposure standards are based on time weighted averages. The TWA is the average exposure over an eight (8) hour work day. Some substances have Ceiling (C) limits. Ceiling limits are concentrations that should never be exceeded.
The SDS will list the occupational health standard(s) for the hazardous chemical or each component of a mixture.
Section 5- Glossary of Terms
5.1 Glossary of Terms (back to top)
ACGIH- The American Conference of Governmental Industrial Hygienists is a voluntary membership organization of professional industrial hygiene personnel in governmental or educational institutions. The ACGIH develops and publishes recommended occupational exposure limits each year called Threshold Limit Values (TLV's) for hundreds of chemicals, physical agents, and biological exposure indices.
ACUTE- Short duration, rapidly changing conditions.
ACUTE EXPOSURE- An intense exposure over a relatively short period of time.
ANSI- The American National Standards Institute is a voluntary membership organization (run with private funding) that develops consensus standards nationally for a wide variety of devices and procedures.
ASPHYXIANT- A chemical (gas or vapor) that can cause death or unconsciousness by suffocation. Simple asphyxiants, such as nitrogen, either remove or displace oxygen in the air. They become especially dangerous in confined or enclosed spaces. Chemical asphyxiants, such as carbon monoxide and hydrogen sulfide, interfere with the body's ability to absorb or transport oxygen to the tissues.
BOILING POINT- The temperature at which the vapor pressure of a liquid equals atmospheric pressure or at which the liquid changes to a vapor. The boiling point is usually expressed in degrees Fahrenheit. If a flammable material has a low boiling point, it indicates a special fire hazard.
"C" OR CEILING- A description usually seen in connection with ACGIH exposure limits. It refers to the concentration that should not be exceeded, even for an instant. It may be written as TLV-C or Threshold Limit Value-Ceiling. (See also THRESHOLD LIMIT VALUE).
CARCINOGEN- A substance or physical agent that may cause cancer in animals or humans.
C.A.S. NUMBER- Identifies a particular chemical by the Chemical Abstracts Service, a service of the American Chemical Society that indexes and compiles abstracts of worldwide chemical literature called Chemical Abstracts.
cc- Cubic centimeter, a volumetric measurement, which is also equal to one milliliter (ml).
CHEMICAL- As broadly applied to the chemical industry, an element or a compound produced by chemical reactions on a large scale for either direct industrial and consumer use or for reaction with other chemicals.
CHEMICAL REACTION- A change in the arrangement of atoms or molecules to yield substances of different composition and properties. (see REACTIVITY)
CHRONIC- Persistent, prolonged or repeated conditions.
CHRONIC EXPOSURE- A prolonged exposure occurring over a period of days, weeks, or years.
COMBUSTIBLE- According to the DOT and NFPA, combustible liquids are those having a flash point at or above 100oF (37.8oC), or liquids that will burn. They do not ignite as easily as flammable liquids. However, combustible liquids can be ignited under certain circumstances, and must be handled with caution. Substances such as wood, paper, etc., are termed "Ordinary Combustibles".
CONCENTRATION- The relative amount of a material in combination with another material. For example, 5 parts of (acetone) per million (parts of air).
CORROSIVE- A substance that, according to the DOT, causes visible destruction or permanent changes in human skin tissue at the site of contact or is highly corrosive to steel.
CUBIC METER (m3)- A measure of volume in the metric system.
CUTANEOUS- Pertaining to or affecting the skin.
DECOMPOSITION- The breakdown of a chemical or substance into different parts or simpler compounds. Decomposition can occur due to heat, chemical reaction, decay, etc.
DERMAL- Pertaining to or affecting the skin.
DERMATITIS- An inflammation of the skin.
DILUTION VENTILATION- See GENERAL VENTILATION.
DOT- The United States Department of Transportation is the federal agency that regulates the labeling and transportation of hazardous materials.
DYSPNEA-Shortness of breath; difficult or labored breathing.
EHS- Environmental Health and Safety
EPA- The Environmental Protection Agency is the governmental agency responsible for administration of laws to control and/or reduce pollution of air, water, and land systems.
EPA NUMBER- The number assigned to chemicals regulated by the Environmental Protection Agency (EPA).
EPIDEMIOLOGY- The study of disease in human populations.
ERYTHEMA- A reddening of the skin.
EVAPORATION RATE- The rate at which a material is converted to vapor (evaporates) at a given temperature and pressure when compared to the evaporation rate of a given substance. Health and fire hazard evaluations of materials involve consideration of evaporation rates as one aspect of the evaluation.
oF- Degrees, Fahrenheit; a temperature scale.
FLAMMABLE LIQUID- According to the DOT and NFPA a flammable liquid is one that has a flash point below 100oF. (See FLASH POINT)
Flammable Liquid Class
|Class:||Boiling Point:||Flash Point:|
|Class 1A||< 100oF||< 73oF|
|Class 1B||>= 100oF||< 73oF|
|Class 1C||>= 100oF||>= 73oF and < 100oF|
FLASH POINT - The lowest temperature at which a liquid gives off enough vapor to form an ignitable mixture with air and burn when a source of ignition (sparks, open flames, cigarettes, etc.) is present. Two tests are used to determine the flash point: open cup and closed cup. The test method is indicated on the SDS after the flash point.
GENERAL VENTILATION- Also known as general exhaust ventilation, this is a system of ventilation consisting of either natural or mechanically induced fresh air movements to mix with and dilute contaminants in the workroom air. This is not the recommended type of ventilation to control contaminants that are highly toxic, when there may be corrosion problems from the contaminant, when the worker is close to where the contaminant is being generated, and where fire or explosion hazards are generated close to sources of ignition (See LOCAL EXHAUST VENTILATION).
GRAM (g)- A metric unit of weight. One ounce equals 28.4 grams.
GRAMS PER KILOGRAM (g/Kg) - This indicates the dose of a substance given to test animals in toxicity studies. For example, a dose may be 2 grams (of substance) per kilogram of body weight (of the experimental animal).
HAZARDOUS MATERIAL- Any substance or compound that has the capability of producing adverse effects on the health and safety of humans.
IGNITABLE- A solid, liquid or compressed gas that has a flash point of less than 140oF. Ignitable material may be regulated by the EPA as a hazardous waste, as well.
INCOMPATIBLE- The term applied to two substances to indicate that one material cannot be mixed with the other without the possibility of a dangerous reaction.
INGESTION- Taking a substance into the body through the mouth, such as food, drink, medicine, or unknowingly as in contaminated hands or cigarettes, etc.
INHALATION- Breathing in of an airborne substance that may be in the form of gases, fumes, mists, vapors, dusts, or aerosols.
INHIBITOR- A substance that is added to another to prevent or slow down an unwanted reaction or change.
IRRITANT- A substance that produces an irritating effect when it contacts skin, eyes, nose, or respiratory system.
KILOGRAM (Kg)- A unit of weight in the metric system equal to 2.2 pounds.
LETHAL CONCENTRATION 50- The concentration of an air contaminant (LC50) that will kill 50 percent of the test animals in a group during a single exposure.
LETHAL DOSE 50- The dose of a substance or chemical that will (LD50) kill 50 percent of the test animals in a group within the first 30 days following exposure.
LITER (L)- A measure of capacity. One quart equals .9 liters.
LOCAL EXHAUST VENTILATION- (Also known as exhaust ventilation.) A ventilation system that captures and removes the contaminants at the point where they are being produced before they escape into the workroom air. The system consists of hoods, ducts, a fan and possibly an air cleaning device. Advantages of local exhaust ventilation over general ventilation include: it removes the contaminant rather than dilutes it; it requires less air flow and thus is more economical over the long term; and the system can be used to conserve or reclaim valuable materials. However, the system must be properly designed with the correctly shaped and placed hoods, and correctly sized fans and duct work.
LOWER EXPLOSIVE LIMIT (LEL)- (Also known as Lower Flammable Limit). The lowest concentration of a substance that will produce a fire or flash when an ignition source (flame, spark, etc.) is present. It is expressed in percent of vapor or gas in the air by volume. Below the LEL or LFL, the air/contaminant mixture is theoretically too "lean" to burn. (See also UEL).
MELTING POINT- The temperature at which a solid changes to a liquid. A melting range may be given for mixtures.
MILLIGRAM (mg)- A unit of weight in the metric system. One thousand milligrams equal one gram.
MILLIGRAMS PER CUBIC METER (mg/m3)- Units used to measure air (mg/m3) concentrations of dusts, gases, mists, and fumes.
MILLIGRAMS PER KILOGRAM (mg/kg)- This indicates the dose of a substance (mg/kg) given to test animals in toxicity studies. For example, a dose may be 2 milligrams (of substance) per kilogram of body weight (of the experimental animal).
MILLILITER (ml)- A metric unit used to measure capacity. One milliliter equals one cubic centimeter. One thousand milliliters equal one liter.
MSHA- The Mine Safety and Health Administration; a federal agency that regulates the mining industry in the safety and health area.
MUTAGEN- Anything that can cause a change (or mutation) in the genetic material of a living cell.
NARCOSIS- Stupor or unconsciousness caused by exposure to a chemical.
NFPA- The National Fire Protection Association is a voluntary membership organization whose aims are to promote and improve fire protection and prevention. NFPA has published 16 volumes of codes known as the National Fire Codes. Within these codes is Standard No. 704, Identification of the Fire Hazards of Materials. This is a system that rates the hazard of a material during a fire. These hazards are divided into health, flammability, and reactivity hazards and appear in a well-known diamond system using from zero through four to indicate severity of the hazard. Zero indicates no special hazard and four indicates severe hazard.
NIOSH- The National Institute of Occupational Safety and Health is a federal agency that among its various responsibilities trains occupational health and safety professionals, conducts research on health and safety concerns, and tests and certifies respirators for workplace use.
ODOR THRESHOLD- The minimum concentration of a substance at which a majority of test subjects can detect and identify the substance's characteristic odor.
ORAL- Having to do with the mouth.
OSHA- The Occupational Safety and Health Administration - a federal agency under the Department of Labor that publishes and enforces safety and health regulations for most businesses and industries in the United States.
OXIDATION- The process of combining oxygen with some other substance in a chemical reaction in which an atom loses electrons.
OXIDIZER- Is a substance that gives up oxygen easily to stimulate combustion of organic material.
OXYGEN DEFICIENCY- An atmosphere having less than the normal percentage of oxygen found in normal air. Normal air contains 21% oxygen at sea level.
PERMISSIBLE EXPOSURE LIMIT (PEL)- An exposure limit that is published and enforced by OSHA as a legal standard. PEL may be either a time-weighted-average (TWA) exposure limit (8 hour), a 15-minute short term exposure limit (STEL), or a ceiling (C). The PEL's are found in Tables Z-1, Z-2, or Z-3 of OSHA regulations 1910.1000. (See also TLV).
PERSONAL PROTECTIVE EQUIPMENT (PPE) - Any devices or clothing worn by the worker to protect against hazards in the environment. Examples are respirators, gloves, and chemical splash goggles.
POLYMERIZATION- A chemical reaction in which two or more small molecules combine to form larger molecules that contain repeating structural units of the original molecules. A hazardous polymerization is the above reaction with an uncontrolled release of energy.
ppm- Parts (of vapor or gas) per million (parts of air) by volume.
REACTIVITY- A substance's susceptibility to undergoing a chemical reaction or change that may result in dangerous side effects, such as explosions, burning, and corrosive or toxic emissions. The conditions that cause the reaction, such as heat, other chemicals, and dropping, will usually be specified as "Conditions to Avoid" when a chemical's reactivity is discussed on a SDS.
RESPIRATOR- A device which is designed to protect the wearer from inhaling harmful contaminants.
RESPIRATORY HAZARD- A particular concentration of an airborne contaminant that, when it enters the body by way of the respiratory system or by being breathed into the lungs, results in some bodily function impairment.
SENSITIZER- A substance that may cause no reaction in a person during initial exposures, but afterwards, further exposures will cause an allergic response to the substance.
SHORT TERM EXPOSURE LIMIT- Represented as STEL or TLV-STEL, this is the maximum concentration to which workers can be exposed for a short period of time (15 minutes) for only four times throughout the day with at least one hour between exposures. Also the daily TLV-TWA must not be exceeded.
"SKIN" - This designation sometimes appears alongside a TLV or PEL. It refers to the possibility of absorption of the particular chemical through the skin and eyes. Thus, protection of large surface areas of skin should be considered to prevent skin absorption so that the TLV is not invalidated.
SUBSTANCE- Any chemical entity.
SYNONYM- Another name by which the same chemical may be known.
SYSTEMIC- Spread throughout the body; affecting many or all body systems or organs; not localized in one spot or area.
TERATOGEN- An agent or substance that may cause physical defects in the developing embryo or fetus when a pregnant female is exposed to that substance.
THRESHOLD LIMIT VALUE- Airborne concentrations of substances devised by the ACGIH that represent conditions under which it is believed that nearly all workers may be exposed day after day with no adverse effect. TLV's are advisory exposure guidelines, not legal standards that are based on evidence from industrial experience, animal studies, or human studies when they exist. There are three different types of TLV's: Time Weighted Average (TLV-TWA), Short Term Exposure Limit (TLV-STEL) and Ceiling (TLV-C). (See also PEL.)
TIME WEIGHTED AVERAGE- The average time, over a given work period (e.g. 8-hour work day), of a person's exposure to a chemical or an agent. The average is determined by sampling for the contaminant throughout the time period. Represented as TLV-TWA.
TOXICITY- The potential for a substance to exert a harmful effect on humans or animals and a description of the effect and the conditions or concentrations under which the effect takes place.
TRADE NAME- The commercial name or trademark by which a chemical is known. One chemical may have a variety of trade names depending on the manufacturers or distributors involved..
UNSTABLE LIQUID- A liquid that, in its pure state or as commercially produced, will react vigorously in some hazardous way under shock conditions (i.e., dropping), certain temperatures, or pressures.
UPPER EXPLOSIVE LIMIT (UEL) - Also known as Upper Flammable Limit (UFL). Is the highest concentration (expressed in percent of vapor or gas in the air by volume) of a substance that will burn or explode when an ignition source is present. Theoretically above this limit the mixture is said to be too "rich" to support combustion. The difference between the LEL and the UEL constitutes the flammable range or explosive range of a substance. That is, if the LEL is 1ppm and the UEL is 5ppm, then the explosive range of the chemical is 1ppm to 5ppm. (see also LEL).
VAPOR- The gaseous form of substances, which are normally in the liquid or solid state (at normal room temperature and pressure). Vapors evaporate into the air from liquids such as solvents. Solvents with low boiling points will evaporate.
Appendices (back to top)