Laboratory Safety

By Harold Eddleman, Ph. D., President, Indiana Biolab

Like any workplace, your laboratory offers numerous of risks of injury or death. A beginner should not assume a quick reading of this page will protect him in the laboratory.

Beginners usually think about safety after it is too late. This is true of adults as well as kids. Be wise, think about safety first and plan your work accordingly. Almost all of my lab injuries came as I tried to help a student get out of a problem he created. For example, I have cut my hands trying to repair glassware problems caused by a student trying to insert glass tubing into a rubber stopper having an undersized hole or no lubrication. Often such cases result from trying to save a little money (reusing damaged items), trying to save time (working too fast), or trying to work without proper safety equipment. If you don't have the equipment or knowledge to do a job safely, don't attempt the job. Most workplaces offer dangers the beginner has not even recognized. Some of the worst dangers arise because you lack the scientific knowledge to foresee them.

My purpose in writing this is to help you foresee some of the dangers you may encounter. A nice fringe benefit of becoming a safe laboratory worker is that many of the techniques will help you work safely in everyday work and at home. A short manual such as this cannot cover all the safety problems you will encounter. If you study this list often, it may help you develop personal guidelines for working safely in many environments. I suggest you save a copy of this manual on a diskette and then add your own rules during coming years. When you learn to work safely, employers will notice your ability and trust you with more challenging opportunities.

Use the buddy system. Always have a parent or other competent person watching you for errors in safety and to render assistance or summon help. Make sure emergency equipment and emergency phone humbers are at hand. Always attend every safety meeting available to you. I have attended dozens and always learned something.

To make writing and learning easier, I will group the risks by catergories:

General Safety Precautions for Everyday Living

Don't move like a bull in a china shop. I once worked with a graduate student who was constantly splattering acid, bumping items with elbows, pushing items off countertops by trying to crowd one more item onto the surface, and bumping his head against things as he tried to get a better look at an experiment. Learn to move slowly, and stop moving instantly when some part of your body touches something. Otherwise, you may bump against a carelessly moving student and cause him to drop a container of acid.

When moving large or long items, watch that they don't strike objects. Give vocal and printed warnings to your fellow workers, "Hot stuff coming", "Acid on Counter Top", "High Voltage is ON". Place containers of acid or hot liquids so they can't be knocked over. Devise systems so normally cold objects like hotplates and heaters are not picked by bare hands while hot.

Heavy fumes lie on the floor. Gasoline fumes lying on the ground during a cold wet winter day were ignited nearly killing a friend of mine.

Biological Safety

When collecting in nature, avoid poison ivy and other poisonous plants by learning to identify them. Learn to identify poisonous insects, snakes and the habitats where they occur. Don't go collecting in alligator infested waters or threatened a bear or deer with young. Make plenty of noise in grizzly country so you don't accidentally corner an animal. This is not a complete list, but may help you think safely. Plenty of people have ignored the above. Before entering risky environments, get information from the experts. Park rangers are very good sources of information.

Students of nature should learn about hypothermia, avalanche, weather risks, and other risks in areas unfamilar to them. There are rare sites where poisonous gases rise from unnoticed volcanic vents.

Dispose of wastes in an environmentally safe way. When you pour gasoline and other chemicals on the ground, they usually just flow down to the drinking water supply. Never place broken glass in a wastepaper basket because it will injure janitors and ruin the recycle value of the paper.

Chemical Safety

Learn the origin and properties of poisonous gases. The mode of action varies. Some like carbon dioxide and helium are not poisonous, but in high concentrations dilute the oxygen so you can not obtain adequate oxygen. Carbon monoxide binds to hemoglobin so that body cells do not get enough oxygen and you pass out without knowing the gas was present. Hydrogen cyanide blocks the electron transport system and you die from failure of breathing systems or nervous systems. Even gases which are easily smelled can be dangerous because you get used to the odor. A girl was working on a qualitative analysis science project at school. Her father found her nearly dead on the floor poisoned by hydrogen sulfide gas. She passed to unconcious without realising the gas was so concentrated. She should have had a buddy watching from a safe distance and had more venilation.

Some poisonous gases are heavier that air and may concentrate on the floor. Chlorine is an example. If you must generate poisonous gases, conduct the work in a tested exhaust hood suitable for the work. Be sure you know the principles of operation of such hoods. Few people operate exhaust hoods correctly.

Explosions are a major risk in chemical labs. Most explosives are carbon or nitrogen compounds. Nitrogen is happy to occur as a free gas (74 % of air is N). Many high explosives break down to nitrogen gas and release lots of heat which causes the gases to expand greatly. Using oxygen is risky because ignition of flammable materials may occur. Many hydrocarbons evaporate easily to form explosive mixtures with air. Powdered starch and other organic solids can be explosive when a dust of it is ignited in air.

Sometimes glassware explodes when pressure builds inside due to closed vents. Evaporation of a hydrocarbon may lower the temperature so that water vapor condenses and freezes blocking vents. Or operator error can cause pressure build up. Once I was using air pressure to move a culture of E. coli into a large fermenter. I thought I had the opening between the flask of E. coli and the fermenter open The passage was not open and the 6 liter flask instantly exploded into tiny pieces. I was covered with glass shards. Unbelieveably I did not suffer a single cut. Luckily I was wearing goggles and a heavy lab coat. Before pressurizing any vessel make sure you have adequate safety vents and that they are open and free of ice or debris.

Careful chemists have suffered serious explosions. Often the explosions were due to properties unknown before the explosion. Other times the explosions are due to formation of unexpected compounds. For example, every chemists knows ether is highly volatile and can form explosive mixtures with air, but old ether contains enough epoxides to pose additional risk of explosion. Thus technical grade chemicals may present unexpected risks.

This is not a complete list of chemical risks.

Electrical Safety

Flashight batteries offer 1.5 volts DC which is harmless, but such batteries can explode in fire or during recharging. Automobile batteries are 12 volts DC which is regarded as harmless, but there is rumor of risks. High DC voltages are dangerous but I do not have the facts available. Furthermore, 12 volt auto batteries contain strong sulfuric acid which will injure eyes, wounds, and clothing. This does not mean low voltage DC circuits are harmless. In a circuit without resistance, the current flow can be so high that the wires get hot and you may burn your skin. Tiny wires can explode due to such overheating and flying molten metal can injure your eyes. A common example is the flash explosion of fine aluminum wires in oxygen in a flash bulb.

Some principles of electrical safety:

Another risk is shorts. A circuit may be perfectly safe, but if you let bare wires touch, electricity will take the shortest possible path (short circuit). Thus a motor may be operating safely on the rated voltage, but if the supply cord is damaged and frayed wires touch, the electricity will take the path of least resistance instead of passing thru the motor windings which have higher resistance. There will be sparks as the fine wires melt in a flash of light and molten metal flying. A fire may start or the molten mental may damage your eyes or burn craters in your skin and clothing. Wearing safety glasses and face shields are obvouis precautions.

Electrocution occurs when you become a part of an electric cirucuit. Never hold one wire in one hand and the other wire in the other hand. The current would pass thru your chest near the heart and the salt in blood and salt in your perspiration makes a pretty good conductor. A pretty feeble current passing thur your chest can disrupt your heartbeat and cause death when no damage to the heart actually occurred. Instead of holding one wire in each hand, attach one wire to the circuit then pick up the other wire. This is still very risky, because circuits commonly have one wire grounded to earth and if you touch the hot wire while touching earth, water pipes or another earthed ground, you will be be shocked. There is a third risk. Due to a defect unsuspected high voltage may be present. I once destroyed two years income that way. My son and I were building a computer system, we had checked all voltages and found them to be 5 volts or 12 volts as desired. But because we failed to check the polarity of an autotransformer, the chassis ground was floating 120 VAC above earth and when we connected the computer there were a few faint sounds and none of the equipment survived. In another instance I plugged a modem in one outlet and the computer in another. It was destroyed because the electrician had reversed the hot and neutral wires on one outlet. That outlet normally ran the air conditioner. If anyone had touched the air condirtion frame while standing on the wet soil, he would have received 110 volts, enough to kill. Any time equipment gives a shock, get it checked out by a competent electrician. Hardware stores sell cheap teasters having a standard 3 wire plug and 3 display neon diodes (2 yellow and 1 red). Use one of these to test the wall outlets in your house for correct wiring.

Learn the fundamentals of electricity and electrical circuits. The preceeding is not a complete guide to electrical risks. If you use high voltages, install safety interlocks so that the equipment can not be opened without opening the power circuit.

Fire Safety

Alcohol lamps are often used in microbiology labs. When they spill, the flames are mostly invisible and a student can place his hand in the flame. Here is an example that alcohol lamps are not needed: I have planted 100,000 tissue cultures entering each 10 times without flaming my tools after dipping them in alcohol. That is one million operations without a single contamination incident or killing of plants by the alcohol. (The preceeding work was done in a laminar flow hood, but many of the source cultures had contamination requiring use of alcohol). People have run through invisible alcohol flams with tragic results at auto race tracks.

In the event of a fire, concentrate on getting the fire out. Worry about damage to the experiment afterward. Usually, carbon dioxide fire extinguishers are best. Learn the uses of each type of fire extinguisher. Kept them filled and ready to use.

This is not a complete manual on fire safety.

Immunological Safety

Repeated exposure to an antigen (usually proteins) can cause a person to develop antibodies against the antigen. Thus, people may become allergic to household dusts such as dust mites or their droppings. Mites are very common in carpets and beds where shed skin cells and other foods accumulate. Sometimes people working several years with insects or other animals (household pets) become allergic to substances they emit. A laboratory working with tobacco hornworm had a small room where the moths could fly. Some workers became allergic. Some say the scales from butterflies and moths are quite good antigens.

In 1964, after working 5 years with Tribolium castaneum, a flour beetle, I was separating pupae from the flour in a huge culture every hour for several days. Each time I performed the task, my nose began running as if I had a head cold. When I left the room, my discomfort faded away. Perhaps, I had become allergic to the flour or something given off by the beetles. I suspect the flour, because it rose as a cloud from the sifting operation. Thus, it may be wise when running a big project to consider the possibility of developing an allergy which will affect your ability to continue the project. Perhaps, I should have worn a mask to filter the dusk from the air.

Microbiological Safety

Many scientists have contracted diseases they were studying and died. Nurses and others caring for the sick face that risk. Pathogens are organisms which are known to cause disease in any plant or animal. Those known to cause disease in humans are called human pathogens. Some animal pathogens cause disease in humans; some don't.

The following persons have above average risk of infection by microbes:

Some principles of microbiological safety are:

Radiological Safety

Man has always been exposed to natural radiations. These include visible radiations from sun, fire, and fireflies, infrared from fire and sun, ultraviolet from sun, cosmic particles from unknown source, and alpha, beta, and gamma radiations from reactions in atmosphere or geologic sources including water. There is no reason to have a wild fear of radiation because man has some defenses against weak radiations and some research suggests a little radiation may be a good thing, but that may be false and due to experimental error.

Visible radiations are harmless unless too strong on the retina of the eye.

Infared radiations are called heat waves because they warm surfaces that absorb them. Everyone knows too much heat is harmful. Infared radiations are common used in chemical analyses and are can be handled safely.

Ultraviolet light from the sun can cause sunburn as everyone has discovered. Spreading compounds which have congugated double bonds, sold as sunscreens, on your skin is helpful because they trap the UV energy before it can reach similar important molecules in your body. Welders are aware that the ultraviolet light from the electrical arc causes similar burn. Never look at a ultraviolet source such as the sun, electrical arc, or UV lamp because the radiations damage the eye (retina?). Since DNA, proteins, and many other biochemicals absorb UV radiations of various wavelengths, UV radiations are useful in chemical analysis--just don't look at the UV lamp. When nucleic acid absorbs the energy of a UV radiation, the excited state may cause a molecular rearrangement which leads to a mutation. Most mutations are non-beneficial. For example cell division may be affected so that cells multiply too much (a tumor or cancer). See the genetics pages for further discussion.

Place discussion of other radiations here soon as possible.

Shop Safety (power tools)

Many science projects require you to be your own instrument maker. I have always urged my high school students to enroll in shop classes that include mechanical drawing. Experience in drafting will help you explain designs to instrument makers and will help you draw nice graphs and also aid you in drawing pictures of plants, muscles, and other illustrations. Most universities where I have worked had shops where I could build my own instruments or at least help the instrument maker get started. Shop skills from my high school days helped me build many instruments. The shop experience also helped me conceive new instrument designs. Good shop courses include lots of safety instruction: hearing protection, eye protection, safe methods of working.

Some principles of shop safety:


Legal disclaimer: No one makes any claim that the above information is complete or free of errors.

Email comments to Harold Eddleman (indbio@disknet.com)