Web-like, they stretch from wall to wall. Snaking behind equipment and under desks, strung together and strewn over light fixtures and across the top of the fume hoods like orange and black garlands. Poking through holes in walls and ceiling tiles, taped up, stapled down, and snarled into knots that would give sailors nightmares. Often, one grows to several, and then sometimes to even more. Used in the office and lab alike, stretching resources to levels never imagined, often taxing the system well beyond its intended design. What are we talking about? Extension cords, along with cord- and plug-powered equipment, some of the most indispensable tools we use today, but often with little consideration and used in a fashion that could potentially have disastrous results.
According to the Consumer Product Safety Commission (CPSC), electrical cords and plugs were involved in about 7,100 fires resulting in 120 deaths in 1996. In 1997, more than 12,000 people were treated for electrical shocks and burns. About 2,500 of them were treated for injuries stemming from extension cords.1 The CPSC goes on to say, “Old extension cords, power strips and surge protectors may have undersized wires, loose connections, faulty components or improper grounding. Old extension cords may fail to meet current safety standards and can be overloaded easily.
With a little care, some culling of old equipment and a few precautions, these conveyors of power can be used safely. One warning, if you have more than a few extension cords powering equipment in your lab, it is probably time to call an electrician to install additional strategically placed outlets, or rearrange equipment. Likewise, if you have any cords running through walls, up through the ceiling, and down to somewhere else, an electrician is definitely required. Extension cords should only be used when necessary and only temporarily. You should always plug equipment directly into a permanent outlet whenever possible. One notable exception is the use of power strips for computer workstations; many jurisdictions permit these as they have internal circuit breakers to provide protection at the point of use. Over the next couple of years we will see a shift to arc-fault protection on these devices as well. Some jurisdictions are already requiring this safety feature. Wherever it is not possible to plug equip ent directly into an outlet, you should begin by selecting the right cord for the job. We generally recommend you purchase cords with polarized, three-prong plugs (ground pin equipped with different size blades) that are approved for both indoor and outdoor use. Note: if power is needed in an approved, flammable liquid storage/dispensing room, there will generally be very specific power cord and plug configurations with specific, testing lab approvals for use in these areas; these are not off-the-shelf items. The cord should have a certification label from an independent testing lab, such as UL (Underwriters Laboratories) or ETL (Electrical Testing Laboratories) on the package and attached to the cord. The advantage of the three- prong (grounded) cord is you would be able to use it on almost any equipment. The two-prong cord sets, while fine for some equipment, cannot be used with equipment needing a path to ground (the third prong).
The cord must be able to handle the intended load. The manufacturer’s label on the cord and package should provide the maximum wattage the cord can safely carry. This, in large part, depends on the diameter of the conductors (the copper part of wire). Wires that contain more copper can safely handle more power. The gauge of the wire describes the wire size. You would think that a 16-gauge wire is bigger than a 12-gauge wire, but it’s not! As the number gets smaller, the thickness of the conductor gets bigger. A 12-gauge wire can safely carry much more power than a 16-gauge wire.
Always use the shortest extension cord possible to minimize risk of damage to the cord and reduce electrical resistance through the length of the cord. You have picked out your cord, is it safe to use? Extension cords, by the nature of their length and conditions of use, are much more prone to damage than other types of wiring. It is important to check the total length of the cord for damage before putting in use. One should start by looking at the ends of the cords. The male end — the end with the three prongs that fit into an electrical outlet — is the one most prone to damage. The two flat power-conducting prongs are subject to bending, while the round prong (often called the ground pin), can be broken off. Without the ground pin there is no path to ground through the wires — potentially a very dangerous situation. Most extension and equipment cords have a tough outer layer that is designed to protect the inner wires. If the outer jacket is damaged, the softer inner insulation around the wires can easily become damaged.
Does this mean whip out the tape to repair it? Absolutely not! Damage to an extension cord jacket, or any cord for that matter, should never be fixed by wrapping it with tape. Even electrical tape does not have sufficient strength or abrasion resistance to make a permanent repair as required by OSHA. A taped-up extension or power cord to a piece of equipment is an easy OSHA citation and would make the inspector’s day.
So what to do if you have a damaged cord? Cut off the plug and throw it out and replace it with a new cord. Alternatively, the cord can be cut at the point of damage and a new plug installed. If the female end is damaged, do not use one of those 2- or 4-outlet boxes intended for structural use. These are not permitted if the box is designed to be surface mounted. The clue to easy identification is the presence of indentations (knockouts) on the side about the size of a nickel and small holes on the back. There are hard-walled outlet boxes that are approved for use with a flexible cord or on a pendant. Next, where to plug it in? If you are in a wet or damp location, or next to a water source look for outlets protected by Ground Fault Circuit Interrupters (GFCIs). GFCI are fast-acting devices that detect small current leakage from electrical equipment. In other words, it senses electricity traveling to ground via something other than the wires, such as you. It shuts off the electricity within 1/40 of a second if sufficient current leakage is detected. It provides effective protection against shocks and electrocution.
GFCI pigtails, very short cords with a GFCI built in, can be used with plug and cord equipment in areas without protected outlets. Although GFCI outlets are required by building codes in bathrooms, kitchens, rooftops, and garages, they are not always required near laboratory sinks. This requirement varies by locale and code enforcement authority. However, we think it is a good idea and almost always recommend them on outlets within six feet of laboratory sinks.
The physical hazards of chemicals are often the best understood. These hazard classes include flammability, reactivity, explosivity, and corrosivity. In the laboratory there are a few materials of note that present physical hazards. Diethyl and isopropyl ethers are extremely flammable and are often some of the most dangerous fire hazards often found in the laboratory. This is due to their high volatility and extremely low flash point. Electrical arcs from equipment motors and switches or from static electricity discharges may ignite ether vapors. Most flammable liquids have vapors that are heavier than air and may travel surprisingly long distances to an ignition source and flash back. Never use a household- type refrigerator to store flammable liquids (ethers, alcohols, etc). In the event of a container spill or leak, an explosive concentration can quickly develop with ignition occurring when the unit cycles. Every year or two there is a new story of a university lab destroyed as a result of a refrigerator fire. Many ethers, tetrahydrofuran, dioxane, and several other flammable solvents have the additional hazard of forming unstable peroxides over time, especially with exposure to air. When sufficiently concentrated (e.g. around a container cap or through distillation) detonation can occur. Because of their tendency to form peroxides on contact with air, date containers upon receipt and at the time they are opened. Many organizations require peroxide formers to be either disposed of, or tested, within three to six months after opening. If unopened, they should always be disposed of by the expiration date on the container.
Flammable and combustible liquids (including organic acids) are best stored in Factory Mutual (FM) approved flammable liquid storage cabinets or in a specially designed flammable liquid storage room. There are often local and state requirements or fire codes that limit quantities of flammable liquids and other classes of chemicals within portions of a building and within the building as a whole. Chemical compatibility is critical when storing chemicals. Inadvertent mixing of incompatible chemicals may result in fire, explosion, or evolution of extremely toxic gasses.
On a frequency basis we have probably seen more reported injuries in lab settings from corrosives (acids and bases) than any other class of chemical. In part, this is due to the fact that the pain starts within seconds (or hours with inhalation of some acid vapors) and thus is tied directly to the exposure event. Of these injuries, spray/splash to the eyes is near the top of the list and is among the most preventable. The use of protective eye wear is paramount wherever chemicals are mixed, dispensed, or used. Using regular prescription glasses alone does not count as protection. If one is not using protective eye wear when using chemicals, then a splash to an eye should not be considered an accident. It is a planned event. One may not know exactly when it will happen, but chances are, sooner or later it will. If a chemical splash or spray to the eyes or skin does occur, prompt action can greatly reduce the severity of injury.
Time is critical and seconds count. Unless flushed immediately and thoroughly, tissue destruction may occur. Corrosives denature eye proteins causing them to become opaque (just as when you fry an egg and the albumin goes from clear to white). This is not reversible, you can’t unfry an egg. You should know exactly where the nearest safety shower and eyewash is for each part of the facility in which you work. The open area under the safety shower is often choice space for putting boxes or storing a cart. Resist the temptation and keep access to it free and clear of obstacles. One day you may need to find it quickly and with your eyes closed.
Many chemical suppliers offer plastic dipped reagent bottles to prevent release of the chemical if struck or dropped. In several close calls we have seen, this system worked well to prevent spilling and injury, and was well worth the slight extra cost.
As we have seen, there can be many hazards in the laboratory associated with the physical hazards of chemicals. In any experiment or chemical process it makes sense to pre-plan the procedure with a thorough understanding of the experiment and the role and properties of each of the materials used. Incorporating safety planning into the procedure or experiment should be a natural and integral part of this process. We will continue the discussion of chemical safety in the next issue with a focus on the toxicity and other biological concerns of chemical exposures. As always, make safety in the lab a habit for life.
The thought of using “chemicals” can bring about a wide range of individual emotions in people. These may range from a total lack of concern and contempt for any suggestion of hazard, to overwhelming apprehension at the thought of the slightest exposure. In reality, the mishandling of many chemicals can have serious health and safety consequences. However, even the most dangerous chemicals can be used with a high degree of safety in the laboratory if people recognize the hazards to which they may be exposed, are trained to deal with those hazards, are diligent and consistent in the use of appropriate safeguards, and are committed to preventing injuries and illnesses.
KNOWING THE HAZARDS
The OSHA Hazard Communication Program (HCP) and the OSHA Chemical Hygiene Plan (CHP) are cornerstones for chemical safety and health in the workplace1. The plans are similar, in that the goal of each is to have workers understand the chemical hazards to which they may be exposed and understand how to adequately protect themselves from those hazards. In addition, the CHP also requires the development of standard operating procedures (SOPs) for using laboratory chemicals that describe the hazards and what measures will be used to protect against them. The SOP basically requires the laboratory worker to pre-think and preplan the experiment to account for and address the potential hazards. We always like to see notation in the lab notebook addressing the SOP elements when designing an experiment (e.g. do in fume hood, use nitrile gloves, etc.). The CHP covers the use of materials that meet the OSHA definition of “laboratory scale” and “laboratory use:”
“Laboratory scale” means work with substances in which the containers used for reactions, transfers, and other handling of substances are designed to be easily and safely manipulated by one person. “Laboratory scale” excludes those processes whose function is to produce commercial quantities of materials. “Laboratory use” means handling or use of chemicals in which all of the following conditions are met:
(i) Chemical manipulations are carried out on a “laboratory scale”
(ii) Multiple chemical procedures or chemicals are used
(iii)The procedures involved are not part of a production process, nor in any way simulate a production process
(iv)“Protective laboratory practices and equipment” are available and in common use to minimize the potential for employee exposure to hazardous chemicals
Those uses of chemicals in the laboratory that do not meet the requirements above, such as filling vacuum pumps with oil, some uses of tissue fixatives, use of liquid nitrogen for sample preservation, or use of acrylamide for pouring gels (for those few still doing this) fall under the Hazard Communication Standard (a.k.a. “Haz Com”).
The primary elements for both Haz Com and the CHP include: a chemical inventory; material safety data sheets (MSDS); labeling of containers with the product name and an appropriate hazard warning training of staff on safety and health aspects of using the materials; and development of a written program. MSDS and primary container labels contain much of the safety and health information required to safely work with chemicals. Employees must be trained before they actually usechemicals at work. One method of training and documentation we have seen that can be effective is the use of an “open book/fill in the blank” type quiz. Employees complete the quiz as the training is conducted. They record the key points in their own handwriting as they are being trained. These key points might include a mix of general and sitespecific information (e.g. the written program is available for review and is kept on the bookcase in room 232, MSDS are maintained in a binder in the main office and on top of the file cabinet in the lab). A second training exercise, often used in conjunction with the quiz, is to provide the MSDS for a material commonly used in the facility along with product-specific questions (e.g. phenol has a variety of potential hazards). Employees working either singly, or in groups, use the MSDS to answer the questions. These exercises can help reinforce the information provided during training and provide much more defensible proof of training than a simple sign off sheet.
Diagnostic and health-care laboratories (public health, clinical or hospital-based) must all be designed for Biosafety Level 2 or above. As no laboratory has complete control over the specimens it receives, laboratory workers may be exposed to organisms in higher risk groups than anticipated. This possibility must be recognized in the development of safety plans and policies. In some countries, accreditation of clinical laboratories is required. Globally, standard precautions (2) should always be adopted and practised. The guidelines for basic laboratories – Biosafety Levels 1 and 2 presented here are comprehensive and detailed, as they are fundamental to laboratories of all biosafety levels. The guidelines for containment laboratories – Biosafety Level 3 and maximum containment laboratories – Biosafety Level 4 that follow (Chapters 4 and 5) are modifications of and additions to these guidelines, designed for work with the more dangerous (hazardous) pathogens.
Code of practice
This code is a listing of the most essential laboratory practices and procedures that are basic to GMT. In many laboratories and national laboratory programmes, this code may be used to develop written practices and procedures for safe laboratory operations. Each laboratory should adopt a safety or operations manual that identifies known and potential hazards, and specifies practices and procedures to eliminate or minimize such hazards. GMT are fundamental to laboratory safety. Specialized laboratory equipment is a supplement to but can never replace appropriate procedures. The most important concepts are listed below.
The backbone of the practice of biosafety is risk assessment. While there are many tools available to assist in the assessment of risk for a given procedure or experiment, the most important component is professional judgement. Risk assessments should be performed by the individuals most familiar with the specific characteristics of the organisms being considered for use, the equipment and procedures to be employed, animal models that may be used, and the containment equipment and facilities available. The laboratory director or principal investigator is responsible for ensuring that adequate and timely risk assessments are performed, and for working closely with the institution’s safety committee and biosafety personnel to ensure that appropriate equipment and facilities are available to support the work being considered. Once performed, risk assessments should be reviewed routinely and revised when necessary, taking into consideration the acquisition of new data having a bearing on the degree of risk and other relevant new information from the scientific literature. One of the most helpful tools available for performing a microbiological risk assessment is the listing of risk groups for microbiological agents (see Chapter 1). However, simple reference to the risk grouping for a particular agent is insufficient in the conduct of a risk assessment. Other factors that should be considered, as appropriate, include:
LABORATORY BIOSAFETY MANUAL On the basis of the information ascertained during the risk assessment, a biosafety level can be assigned to the planned work, appropriate personal protective equipment selected, and standard operating procedures (SOPs) incorporating other safety interventions developed to ensure the safest possible conduct of the work. Specimens for which there is limited information The risk assessment procedure described above works well when there is adequate information available. However, there are situations when the information is insufficient to perform an appropriate risk assessment, for example, with clinical specimens or epidemiological samples collected in the field. In these cases, it is prudent to take a cautious approach to specimen manipulation.
Sonicators are high-frequency sound generators used to disrupt cells or shear nucleic acids. Laboratory personnel must be concerned about two of the major hazards associated with sonicators. The first hazard is hearing damage caused by high frequency sound. The second hazard is the generation of aerosols from the sonication process.
Sonicators generate sound waves in the 20,000 Hz range. These sonicator-generated sound waves are outside the normal range of hearing. Often the sound heard while using a sonicator is produced by cavitations of the liquid in the sample container or vibrations from loose equipment. Actions you can take to reduce the hazards include:
Blending, Grinding, Sonicating, Lyophilizing
The greatest hazard when using sonicating and other equipment to disrupt cells or shear nucleic acids is the creation of aerosols. These aerosols are generated by cavitations of the sonicator horn in the sample media and mechanical mixing. The following guidelines should be followed.
Biological hazards can take the form of microbes, recombinant organisms, or viral vectors. They can also take the form of biological agents introduced into experimental animals. Issues such as containment, ability for replication, and potential biological effect all come into play. When designing experiments ensure procedures can be conducted safely. When institutional approval is necessary make certain all the bases are covered.
The most prevalent biological hazards, in terms of frequency of occurrence, are simple allergens associated with the use and care of laboratory animals. Health surveys of people working with laboratory animals show that up to 56% are affected by animal-related allergies. In a survey of 5,641 workers from 137 animal facilities, 23% had allergic symptoms related to laboratory animals. These figures do not include former workers who became ill and could not continue to work.
Labs inherently have significant physical hazards present. Included here are electrical safety hazards, ergonomic hazards associated with material and equipment use and lifting, handling sharps, and basic housekeeping issues.
Electrical hazards are potentially life threatening yet are found much too frequently. First, equip all electrical power outlets in wet locations with ground fault circuit interrupters, or GFCI, to prevent accidental electrocutions. GFCIs are designed to “trip” and break the circuit when a small amount of current begins flowing to ground. Wet locations usually include outlets within six feet of a sink, faucet, or other water source, and outlets located outdoors or in areas that get washed down routinely. Specific GFCI outlets can be used individually or install GFCI in the electrical panel to protect entire circuits.
Another very common electrical hazard is improper use of flexible extension cords. Do not use these as a substitute for permanent wiring. The cord insulation should be in good condition and continue into the plug ends. Never repair cracks, breaks, cuts, or tears with tape. Either discard the extension cord or shorten it by installing a new plug end. Take care not to run extension cords through doors or windows where they can become pinched or cut. And always be aware of potential tripping hazards when using them. Use only grounded equipment and tools, and never remove the grounding pin from the plug ends. Also, do not use extension cords in series; just get the right length cord for the job. Use of hanging pendants and electrical outlets are widespread in labs to help keep cords off floors and out of the way. Check electrical pendants for proper strain relief and type of box used. The box should be totally closed and without any holes. If it contains knockouts or holes for mounting it is not the right type for a hanging pendant.
As a final check for possible electrical hazards, look over your lighting. Protect all lights within seven feet of the floor to guard against accidental breakage. Slip plastic protective tubes over fluorescent bulbs prior to mounting or install screens onto the fixtures.
Many operations in the lab can result in lab workers assuming sustained or repetitive awkward postures. Examples are eluting a column in a fume hood, working for extended periods in a biosafety cabinet, or looking at slides on a microscope for extended periods. What is found acceptable for an occasional use may become problematic if used frequently. Pain is a good indicator something is wrong. Conduct work with a neutral balanced posture. Magnetic assist or programmable pipettes can reduce frequency or hand force required to prevent worker injury. Again we will examine laboratory ergonomics in detail in future issues. Sharps containers are ubiquitous in labs and following a few safety rules can help prevent getting stuck with accident reports. Use only puncture-proof and leak-proof containers that are clearly labeled. Train employees never to remove the covers or attempt to transfer the contents. Make sure they are only used for “sharps” and they get replaced when threefourths full to prevent overfilling. Housekeeping Many injuries stem from poor housekeeping. Slips, trips, and falls are very common yet easily avoided. Start with safe and organized storage areas. Material storage should not create hazards. Bags, containers, bundles, etc., stored in tiers should be stacked, blocked, interlocked, and limited in height so that they are stable and secure against sliding or collapse. Keep storage areas free from accumulation of materials that could cause tripping, fire, explosion, or pest harborage.
Laboratories present many challenges. In the day-to-day bustle, worker health and safety can be easily overlooked. However, with proper guidance, a trained eye, and practice in noticing the mundane, we can find and correct many common mistakes and prevent illness or injury. The Internet provides a vast amount of valuable information easily researched. Begin with the OSHA website (www.osha.gov) and chances are you will find what you need. Be diligent and remember “Safety First!”
Courtesy: Lab Manager Magazine
IN ALL THE HUSTLE OF LOADING THE AUTOSAMPLER, PIPETTING, POURING, AND MIXING FOR EXPERIMENTS, ORKER HEALTH AND SAFETY CAN GET OVERLOOKED. UNDERSTANDING THE REQUIRED OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA) PROGRAMS AND RECOGNIZING HAZARDS WILL HELP YOU TO IDENTIFY AND MINIMIZE MANY OF THE COMMON SAFETY AND HEALTH HAZARDS ASSOCIATED WITH RUNNING A LABORATORY. TO ASSIST YOUR NAVIGATION OF THE HEALTH AND SAFETY MAZE ARE THE “SAFETY GUYS.”
OSHA tells employers that we must provide a workplace “free from recognized hazards.” There are many specific OSHA standards that may apply to laboratories. Most notable is 29CFR1910.1450, “Occupational exposure to hazardous chemicals in laboratories,” also known as the OSHA Lab Standard.1 Other standards include hazard communication, respiratory protection, electrical, and fire safety. In addition, there is a “general duty clause” which covers all other recognized hazards for which specific standards may not exist such as ergonomics and exposures to anesthetic gases or experimental drugs.
DIFFERENT TYPES OF HAZARDS
An important first step in protecting worker health and safety is to recognize workplace hazards. Most hazards encountered fall into three main categories: chemical, biological, or physical. Cleaning agents and disinfectants, drugs, anesthetic gases, solvents, paints, and compressed gases are examples ofchemical hazards. Potential exposures to chemical hazards can occur both during use and with poor storage.
Biological hazards include potential exposures to allergens, infectious zoonotics (animal diseases transmissible to humans), and experimental agents such as viral vectors.
The final category contains the physical hazards. The most obvious are slips and falls from working in wet locations and the ergonomic hazards of lifting, pushing, pulling, and repetitive tasks. Other physical hazards often unnoticed are electrical, mechanical, acoustic, or thermal in nature. Ignoring these can have potentially serious consequences.
Use of chemicals in laboratories is inevitable and the potential for harm or injury could be significant if they are misused or mishandled. OSHA has developed two important standards to help mitigate these potential problems. First is the Hazard Communication standard (29CFR1910.1200). Formerly known as the “Right-to- Know,” it deals with employers’ requirements to inform and train employees on non-laboratory use of chemicals. This would apply to things in the lab such as pump oil, Chromerge, or liquid nitrogen used in dewars. Although these chemicals are found in the lab, their use does not meet the criteria for laboratory use.
The second we’ve already mentioned, known as the “OSHA Lab Standard,” 29CFR1910.1450, requires laboratories to identify hazards, determine employee exposures, and develop a chemical hygiene plan (CHP) including standard operating procedures. The Lab Standard applies to the laboratory use of chemicals and mandates written standard operating procedures (SOPs) addressing the particular hazards and precautions required for safe use. This goes hand-in-hand with experimental design and planning. Chemical safety will be examined in detail in future articles. Both standards recognize the need for material safety data sheets and employee training.