Part III – Criteria for Implementation of Control Measures
Engineering controls, personal protective equipment, hygiene practices, and administrative controls each play a role in a comprehensive laboratory safety program. Implementation of specific measures must be carried out on a case-by-case basis, using the following criteria for guidance in making decisions. Assistance is available from the Environmental Health and Safety.
A. Engineering Controls
Fume Hoods
The laboratory fume hood is the major protective device available to laboratory workers. It is designed to capture chemicals that escape from their containers or apparatus and to remove them from the laboratory environment before they can be inhaled. Characteristics to be considered in requiring fume hood use are physical state, volatility, toxicity, flammability, eye and skin irritation, odor, and the potential for producing aerosols. A fume hood should be used if a proposed chemical procedure exhibits any one of these characteristics to a degree that
· airborne concentrations might approach the action level (or permissible exposure limit),
· flammable vapors might approach one tenth of the lower explosion limit,
· materials of unknown toxicity are used or generated, or
· the odor produced is annoying to laboratory occupants or adjacent units.
Procedures that can generally be carried out safely outside the fume hood include those involving
· water-based solutions of salts, diluted acids, bases, or other reagents,
· very low volatility liquids or solids,
· closed systems that do not allow significant escape to the laboratory environment, and
· extremely small quantities of otherwise problematic chemicals. The procedure itself must be evaluated for its potential to increase volatility or produce aerosols.
In specialized cases, fume hoods will contain exhaust treatment devices, such as water wash-down for perchloric acid use, or charcoal or HEPA filters for removal of particularly toxic or radioactive materials.
Safety Shields
Safety shields, such as the sliding sash of a fume hood, are appropriate when working with highly concentrated acids, bases, oxidizers or reducing agents, all of which have the potential for causing sudden spattering or even explosive release of material. Reactions carried out at non-ambient pressures (vacuum or high pressure) also require safety shields, as do reactions that are carried out for the first time or are significantly scaled up from normal operating conditions.
Other Containment Devices
Other containment devices, such as glove boxes or vented gas cabinets, may be required
when it is necessary to provide an inert atmosphere for the chemical procedure taking place, when capture of any chemical emission is desirable, or when the standard laboratory fume hood does not provide adequate assurance that overexposure to a hazardous chemical will not occur. The presence of biological or radioactive materials may also mandate certain special containment devices. High strength barriers coupled with remote handling devices may be necessary for safe use of extremely shock sensitive or reactive chemicals.
Highly localized exhaust ventilation, such as is usually installed over atomic absorption units, may be required for instrumentation that exhausts toxic or irritating materials to the laboratory environment. Ventilated chemical storage cabinets or rooms should be used when the chemicals in storage may generate toxic, flammable or irritating levels of airborne contamination.
B. Personal Protective Equipment
Bare feet, sandals and open-toed shoes are not permitted in any laboratory. Short pants and short skirts are not permitted in any laboratory, unless covered by a lab coat. Lab coats are strongly encouraged as routine equipment for all laboratory workers. Lab coats are also required when working with select carcinogens, reproductive toxins, substances which have a high degree of acute toxicity, strong acids and bases, and any substance on the OSHA PEL list carrying a "skin" notation.
Eye protection is required for all personnel and any visitors whose eyes may be exposed to chemical or physical hazards. Side shields on safety spectacles provide some protection against flying particles, but goggles or face shields are necessary when there is a greater than average danger of eye contact with liquids. A higher than average risk exists when working with highly reactive chemicals, concentrated corrosives, or with vacuum or pressurized glassware systems. Contact lenses may be worn under safety glasses, goggles or other eye and face protection. Experts currently believe the benefits of consistent use of eye protection outweigh potential risks of contact lenses interfering with eye flushing in case of emergency.
Gloves made of appropriate material are required to protect the hands and arms from thermal burns, cuts, or chemical exposure that may result in absorption through the skin or reaction on the surface of the skin. Gloves are also required when working with particularly hazardous substances where possible transfer from hand to mouth must be avoided. Thus gloves are required for work involving pure or concentrated solutions of select carcinogens, reproductive toxins, substances which have a high degree of acute toxicity, strong acids and bases, and any substance on the OSHA PEL list carrying a "skin" notation.
Since no single glove material is impermeable to all chemicals, gloves should be carefully selected using guides from the manufacturers. However, glove-resistance to various chemicals materials will vary with the manufacturer, model and thickness. Therefore, review a glove-resistance chart from the manufacturer you intend to buy from before purchasing gloves. When guidance on glove selection for a particular chemical is lacking, double glove using two different materials, or purchase a multilayered laminated glove such as a Silvershield or a 4H.
Respiratory protection is generally not necessary in the laboratory setting and must not be used as a substitute for adequate engineering controls. Availability of respiratory protection for emergency situations may be required when working with chemicals that are highly toxic and highly volatile or gaseous. If an experimental protocol requires exposure above the action level (or PEL) that cannot be reduced, respiratory protection will be required. Rarely, an experimental situation may potentially involve IDLH (immediately dangerous to life or health) concentrations of chemicals, which will require use of respiratory protection. All use of respiratory protective equipment is covered under MSUM's Respiratory Protection Program.
C. Hygiene Practices
Eating, drinking and chewing gum are all strictly prohibited in any laboratory with chemical, biological or radioactive materials except in designated break areas. Researchers must also be careful to restrict other actions (such as applying lip balm or rubbing eyes) which could inadvertently cause exposure to research materials. Consuming alcohol or taking illegal drugs in a research laboratory are strictly prohibited; as such actions potentially endanger the health and safety of not only the user, but everyone in the building. Infractions will be met with serious disciplinary action.
Before leaving the laboratory, remove personal protective equipment/clothing (lab coat and gloves) and wash hands thoroughly. Do NOT wear laboratory gloves in public spaces such as hallways and elevators.
D. Administrative Controls
Researchers are strongly encouraged to prioritize research so that work with hazardous chemical, biological or physical agents occurs only during working hours (8 am – 5 pm, Monday through Friday). After-hours work (on nights and weekends) should be restricted to non-hazardous activities such as data analysis and report writing. If hazardous materials must be used at nights or on weekends, ensure that at least one other person is within sight and ear-shot to provide help in an emergency.
Supervisors shall consider the hazards involved in their research, and designate areas, activities, and tasks that require specific types of personal protective equipment as described above.
Part IV -
Management of Chemical Fume Hoods and Other Protective Equipment
A. Monitoring Safety Equipment
Fume hoods must be monitored daily by the user to ensure that air is moving into the hood. Any malfunctions must be reported immediately to the Physical Plant office. The hood should have a continuous reading device, such as a pressure gauge, to indicate that air is moving correctly. Users of older hoods without continuous reading devices should attach a strip of tissue or yarn to the bottom of the vertical sliding sash. The user must ensure the hood and baffles are not blocked by equipment and bottles, as air velocity through the face may be decreased.
Emergency eye washes must be flushed weekly by the user. This will ensure the eye wash is working, and the water is clean, should emergency use become necessary. Environmental Health & Safety will ensure that emergency showers and eye washes are checked annually. Fire extinguishers will be checked monthly by Building Services personnel and annually by a University contractor. The user is responsible for checking regularly to ensure that other protective equipment is functioning properly. Environmental Health and Safety can assist with these evaluations, should assistance be necessary.
B. Acceptable Operating Range
The acceptable operating range for fume hoods is 80 to 150 linear feet per minute, at the designated sash opening (usually 18 inches). If a hood is operating outside of this range check to ensure the baffles are adjusted properly and the exhaust slots are not blocked by bottles and equipment. If these adjustments do not help, report the deficiency to the Physical Plant office for servicing.
C. Maintenance
During maintenance of fume hoods, laboratories must clean out and if necessary, decontaminate the fume hood and restrict use of chemicals to ensure the safety of maintenance personnel. Maintenance personnel will post a warning sign indicating the hood is inoperable during all repairs.
D. Training
Training in the appropriate use and care of fume hood systems, showers, eyewashes and other safety equipment must be included in the initial and update training.
E. New Systems
When new ventilation systems, such as variable air volume exhaust, are installed in University facilities, specific policies for their use will be developed and employees will be promptly trained on use of the new equipment.