Working safely with hazardous chemicals requires proper use of laboratory equipment. Maintenance and regular inspection of laboratory equipment are essential parts of this activity. Many of the accidents that occur in the laboratory can be attributed to improper use or maintenance of laboratory equipment.
The most common equipment-related hazards in laboratories come from devices powered by electricity, devices for work with compressed gases, and devices for high or low pressures and temperatures. Other physical hazards include electromagnetic radiation from lasers and radio-frequency generating devices. Seemingly ordinary hazards such as floods from water-cooled equipment, accidents with rotating equipment and machines or tools for cutting and drilling, noise extremes, slips, trips, falls, lifting, and poor ergonomics account for the greatest frequency of laboratory accidents and injuries. Understandably, injuries to the hands are very common in the laboratory. Care should be taken to use appropriate gloves when handling laboratory equipment to protect against electrical, thermal, and chemical burns, cuts, and punctures.
Working with Water-Cooled Equipment
The use of water as a coolant in laboratory condensers and other equipment is common practice. There could be potential for flooding if pipes carrying water rupture. Refrigerated recirculators are preferred for cooling laboratory equipment to conserve water and to minimise the impact of floods. To prevent freezing at the refrigeration coils, using a mixture of water and ethylene glycol as the coolant is prudent. Spills of this mixture are very slippery and must be cleaned thoroughly to prevent slips and falls.
Electrical Laboratory Equipment
Electrically powered equipment is used routinely for laboratory operations requiring heating, cooling, agitation or mixing, and pumping. There are both mechanical and the electrical hazards inherent in using these devices. Careful handling of these devices is needed as these devices use high-voltage electric current.
Electric shock is the major electrical hazard. Training of all personnel before the use of these devices is mandatory and location of circuit breakers and emergency shut down switches should be known to all.
General Precautions for Working with Electrical Equipment
Laboratory personnel should be certain that all electrical equipment is well maintained, properly located, and safely used. To do this, review the following precautions and make the necessary adjustments prior to working in the laboratory:
- Insulate all electrical equipment properly. Visually inspect all electrical cords monthly, especially in any laboratory where flooding can occur. Keep in mind that rubber-covered cords can be eroded by organic solvents, ozone (produced by ultraviolet lamps), and long-term air oxidation.
- Properly replace all frayed or damaged cords before any further use of the equipment is permitted. Qualified personnel should conduct the replacement.
- Ensure the complete electrical isolation of electrical equipment and power supplies. Enclose all power supplies in a manner that makes accidental contact with power circuits impossible. Use suitable barriers or enclosures to protect against accidental contact with electrical circuits.
- Many laboratory locations are classified under fire and electrical codes with a mandate for non-sparking explosion-proof motors and electrical equipment. Areas where large amounts of flammable solvents are in use also require explosion-proof lighting and electrical fixtures.
- Equip motor-driven electrical equipment used in a laboratory where volatile flammable materials may be present with either non-sparking induction motors that meet Class 1, Division 2, Group C-D electrical standards or air motors. Do not use variable autotransformers to control the speed of an induction motor.
- Because series-wound motors cannot be modified to make them spark-free, do not use appliances (e.g., kitchen refrigerators, mixers, and blenders) with such motors in laboratories where flammable materials may be present.
- Locate electrical equipment to minimise the possibility of spills onto the equipment or flammable vapours carried into it.
- Minimise condensation that may enter electrical equipment if it is placed in a cold room or a large refrigerator.
- If electrical equipment must be placed in such areas, mount the equipment on a wall or vertical panel.
- Condensation can also cause electrical equipment to overheat, smoke, or catch fire. In such a case, shut off the power to the equipment immediately at a main switch or circuit breaker and unplug the apparatus using insulated rubber gloves.
- To minimise the possibility of electrical shock, carefully ground the equipment using a suitable flooring material, and install GFCIs.
- Always unplug equipment before undertaking any adjustments, modifications, or repairs. When it is necessary to handle equipment that is plugged in, be certain hands are dry and, if feasible, wear nonconductive gloves and shoes with insulated soles.
- Ensure that all laboratory personnel know the location and operation of power shutoffs (i.e., main switches and circuit breaker boxes) for areas in which they work.
- After making modifications to an electrical system or after a piece of equipment has failed, do not use it again until it has been cleaned and properly inspected.
Laboratory equipment that can produce hazardous amounts of electromagnetic radiation include ultraviolet lamps, arc lamps, heat lamps, lasers, microwave and radio-frequency sources, and X-ray and electron-beam sources.
Seal or enclose direct or reflected ultraviolet light, arc lamps, and infrared sources to minimise overexposure whenever possible. Wear appropriately rated safety glasses, chemical splash goggles, and face shields for eye protection. Wear long-sleeved clothing and gloves to protect arms and hands from exposure. When lasers or deep UV light sources are in use, lights or highly visible signage should be posted outside the room.
X-rays and electron beams (E-beams) are used in a variety of laboratory applications but most often for analytical operations. The equipment is government regulated, and usually registration and licensing are required. Train personnel operating or working in the vicinity of these types of equipment appropriately to minimise the risk of exposing themselves and others in the laboratory to harmful ionising radiation. The beam from a low-energy X-ray diffraction machine can cause cell destruction as well as genetic damage. The user must always be alert to the on/off status of the X-ray beam, keep aware of the location of the beam, and know how to work safely around the beam when aligning it in preparation for conducting an experiment. Users are required to wear a monitoring badge to measure any accumulated exposure.
Hand injuries are the most frequently encountered injuries in laboratories. Many of these injuries can be prevented by keeping all sharp and puncturing devices fully protected, avoiding the use of razor blades as cutting tools, and using utility knives that have a spring-loaded guard that covers the blade. Appropriate cutting techniques and the use of the proper or specialised tools should also be considered. Dispose of razor blades, syringe needles, suture needles, and other sharp objects or instruments carefully in designated receptacles rather than throwing them into the trash bin unprotected.
Minimise glass cuts by use of correct procedures (e.g., the procedure for inserting glass tubing into rubber stoppers and tubing), through appropriate use of protective equipment, and by careful attention to manipulation. Protective equipment is not fail-safe and should not be relied on to prevent cutting injuries. Any laboratory operation that exposes trained laboratory personnel to a significant noise source of 85 decibels or greater for an 8-hour average duration should have a hearing conservation program to protect from excessive exposure.
The risks of slips, trips, falls, and collisions between persons and objects are reduced by cleaning up liquid or solid spills immediately, keeping doors and drawers closed and passageways clear of obstructions, providing step stools, ladders, and lifts to reach high areas, and walking along corridors and on stairways at a deliberate pace. Floors that are likely to be wet, for example around ice, dry ice, or liquid nitrogen dispensers, should be slip resistant or have a slip-resistant floor covering.
Working with Compressed Gases
Prudent procedures for the use of compressed gas cylinders in the laboratory include attention to appropriate purchase, especially selecting the smallest cylinder compatible with the need, as well as proper transportation and storage, identification of contents, handling and use, and marking and return of the empty cylinder to the company from which it was purchased. Clearly label compressed gas cylinders so they are easily, quickly, and completely identified by trained laboratory personnel. Tags should be used on cylinders for easy identification of users and dates.
All gas lines should be labelled clearly from the point of origin and emergency numbers should be displayed prominently. The labels, in addition to being dated, should be color-coded to distinguish hazardous gases and inert gases. Post signs conspicuously in areas in which flammable compressed gases are stored, identifying the substances and appropriate precautions.
Test or inspect all pressure equipment periodically. The frequency of tests and inspections varies, depending on the type of equipment, how often it is used, and the nature of its usage. In assembling copper-tubing installations, avoid sharp bends and allow considerable flexibility. Copper tubing hardens and cracks on repeated bending.
Working with High or Low Pressures and Temperatures
Work with hazardous chemicals at high or low pressures and high or low temperatures requires planning and special precautions. For many experiments, extremes of both pressure and temperature, such as reactions at elevated temperatures and pressures and work with cryogenic liquids and high vacuum, must be managed simultaneously. Carry out procedures at high or low pressures with protection against explosion or implosion by appropriate equipment selection and the use of safety shields. Provide appropriate temperature control and interlocks so that heating or cooling baths cannot exceed the desired limits even if the equipment fails. Take care to select and use glass apparatuses that can safely withstand thermal expansion or contraction at the designated pressure and temperature extremes.
Using Personal Protective, Safety and Emergency Equipment
Trained laboratory personnel must be proactive to ensure that the laboratory is a safe working environment. This attitude begins with wearing appropriate apparel and using proper eye, face, hand, and foot protection when working with hazardous and infectious materials.
The following general emergency procedures are recommended in the event of a fire, explosion, spill, or medical or another laboratory accident. These procedures are intended to limit injuries and minimise damage if an accident should occur. Post numbers to call in emergencies clearly at all telephones in hazard areas. Because emergency response (personnel, contact information, procedures) varies greatly from institution to institution, all laboratory personnel should be properly trained and informed of the protocols for their particular institution.
- Have someone call for emergency help, for instance, 911 or other number as designated by the institution. State clearly where the accident has occurred and its nature.
- Ascertain the safety of the situation. Do not enter or re-enter an unsafe area.
- Without endangering yourself, render assistance to the personnel involved and remove them from exposure to further injury.
- Warn personnel in adjacent areas of any potential risks to their safety.
- Render immediate first aid; appropriate measures include washing under a safety shower, administration of CPR by trained personnel if heartbeat or breathing or both have stopped, and special first-aid measures.
- Put out small fires by using a portable extinguisher. Turn off nearby equipment and remove combustible materials from the area. For larger fires, contact the appropriate fire department promptly. Be aware that many organisations limit fire extinguisher use to designated trained personnel only.
- Provide emergency personnel with as much information as possible about the nature of the hazard, including a copy of the material safety data sheet (MSDS).
- In a medical emergency, laboratory personnel should remain calm and do only what is necessary to protect life.
- Summon medical help immediately.
- Do not move an injured person unless he or she is in danger of further harm.
- Keep the injured person warm. If feasible, designate one person to remain with the injured person. The injured person should be within sight, sound, or physical contact of that person at all times.
- If clothing is on fire and a safety shower is immediately available, douse the person with water; otherwise, roll the person on the floor to smother the flames.
- If harmful chemicals have been spilled on the body, remove the chemicals, usually by flooding the exposed area with the safety shower, and immediately remove any contaminated clothing.
- If a chemical has splashed into the eye, immediately wash the eyeball and the inner surface of the eyelid with water for 15 minutes. An eyewash unit should be used if available. Forcibly hold the eye open to wash thoroughly behind the eyelid.
- If possible, determine the identity of the chemical and inform the emergency medical personnel attending the injured person. Provide an MSDS for each chemical that is involved in the incident to the attending physician or emergency responders.
A safe working environment starts with proper designing of workplace, proper education and training of all personnel in a laboratory. Training includes how to handle hazardous materials, laboratory equipment and environmental factors, not to forget training to handle emergency situations.