- Animal Procedures
Accidents do happen in Princeton University laboratories. The following
are accounts of a few incidents that help to illustrate the need for the
safety precautions outlined in this manual.
Wall-Mounted Shelves Collapse
There have been several incidents where wall-mounted shelves detached
and fell onto desks and other work surfaces, dumping the shelving
books all over the work area. In one case, a person working nearby
was injured as a result. In each instance, the shelves were heavily
and either exceeded the load capacity of the shelving or was incorrectly
The bottom shelf of an organic chemical storage cabinet spontaneously collapsed. This shelf was not a moveable shelf, but a bottom panel contributing to the structural integrity of the cabinet. Fortunately, the drop was only a few inches and none of the bottles of chemicals were broken.
The cabinet was constructed of thin plywood with particle board shelves
attached to a pressed paperboard backing. This type of cabinet is
appropriate for chemical storage.
Fire/Burn from Heating Flammable Solvent with Heat Gun
A laboratory worker was using a heat gun to heat approximately 0.5 liters of heptane in a Pyrex beaker by hand over an open bench. A splash of heptane came in contact with the elements of the heat gun, igniting the heptane and causing him to toss the beaker away from him. The sleeve of the worker's shirt caught fire. The flaming beaker landed on another work surface, spreading the fire to his computer. The worker immediately used a safety shower to put out the fire on his clothing, then used a dry chemical fire extinguisher to put out the other fire.
The worker received burns to his hand. The computer containing his
thesis was destroyed by the powder from the extinguisher.
A fire erupted inside a hood containing two reactions running unattended. A laboratory worker had placed nitrobenzene inside an oil bath atop a hot plate. The hot plate had been operating for three days, heating the oil bath to 200° C. A plastic squeeze bottle of hexane was placed next to the hot plate. Eventually, the squeeze bottle warmed enough to pressurize the container, forcing liquid hexane out of the bottle and onto the hot plate, where it ignited. Another laboratory noticed the smoke and attempted to put out the fire using a dry chemical extinguisher. A maintenance worker also noticed the fire and assisted the laboratory worker. Their attempts were not successful.
The fire department was dispatched. Since the Emergency
Information Poster on the door to the laboratory was inaccurate
and there was a significant language barrier between the laboratory
worker and the fire department personnel, a hazmat response team was
dispatched. Frick, New Frick and Hoyt were evacuated for more than three
hours. The laboratory worker and the maintenance worker were showered
and scrubbed by the hazmat team and their clothing was confiscated (it
was later washed and returned to them). While this was probably
an overreaction by the emergency response personnel, it illustrates
the implications of not having an accurate, up-to-date emergency information
Hydrofluoric Acid Burn from Trifluoracetic Acid
A laboratory worker picked up a container of trifluoroacetic acid with her ungloved hand to move it. She did not notice that there was a small amount of residue on the glass. Several hours later, she experienced pain in the palm of her hand and the inside aspect of her thumb. The result was a serious burn that required skin grafting. She was not aware that this type of burn could result from handling trifluoracetic acid.
Trifluoracetic acid can form hydrofluoric
acid upon contact with moisture. Hydrofluoric acid can cause deep
burns that may not be painful for hours.
A laboratory worker received burns to the face and chest while carrying
chemicals from one area of the laboratory to another. The worker placed
unsealed centrifuge tubes filled with phenol-chloroform
into a Styrofoam centrifuge tube shipping container. The Styrofoam broke
and the phenol-chloroform splashed onto the worker’s face and dripped
down the chest. The worker immediately flushed the area with a drench
hose, but still suffered from second-degree burns to the face, chest
and abdomen. Fortunately, the worker was wearing chemical
splash goggles and did not receive burns to the eyes.
A laboratory worker was pouring chloroform though a gel column inside a fume hood. Due to incorrect equipment configuration, pressure built up in the column and caused the glassware at the top of the column to break, spraying chloroform out of the hood, onto the worker’s face, eyes and clothing.
The laboratory worker was wearing safety glasses, rather than chemical splash goggles. The chloroform seeped through the opening at the top of the glasses and burned both eyes. The lens of the safety glasses were partially dissolved by the chloroform. The worker did use a safety shower immediately, but was too embarrassed to remove his sweater in the presence of other laboratory workers. As a result, he suffered from second degree burns on both arms where the chloroform soaked through the sweater.
The set-up of the apparatus was changed to allow the hood of the sash
to be lowered when the chloroform is being poured, providing an additional
shield between the worker and the chemical and lowering the potential
spray below eye level.
There have been several incidents, usually involving phenol,
where laboratory workers spilled a chemical on his or her pants. In
all cases, the worker bypassed the safety
shower and entered a restroom to remove the pants and rinse the
leg. In each case, the worker put the contaminated pants back on and
either went home to rinse further or went to University
Health Services at McCosh. All resulted in second degree burns that
could have been minimized by taking off the contaminated clothing and
rinsing immediately using a safety shower or drench hose.
Mixing Incompatible Wastes
A laboratory worker was cleaning out chemicals from an old refrigerator. Wearing gloves, chemical splash goggles and a lab coat (over shorts), the worker was segregating the chemicals into several different waste containers. He found a small bottle of iodine monochloride, and not knowing the physical properties of the chemical, began to pour it into a jar with other liquid wastes. The waste container suddenly began fuming vigorously, startling the worker and causing the worker to drop the bottle of iodine monochloride. Several drops of the chemical splashed onto the worker's leg, causing a second degree burn.
The iodine monochloride reacted with a chemical in the waste container.
The worker was fortunate that the reaction did not produce significant
amounts of hazardous vapors. Had the worker been wearing long
pants, the burn might have been avoided.
Glass Vessel Ruptures (top)
Glass Flask Rupture During Ozonolysis
During an early attempt to scale up a procedure, a laboratory worker introduced ozone gas into a flask containing a small amount of organic material. The flask was set in a fume hood in a cooling bath designed to lower the experiment temperature to -85° C, 15° C below that which is normally used for such experiments. The sash of the fume hood was completely raised. During the procedure, the worker noticed that a deep blue color had developed in the flask, an indication that the concentration of ozone was increased. He attributed it to poor mixing and had started to increase the stir rate when the flask exploded. Flying glass embedded into his face, neck and safety glasses.
The worker did not experience any injuries to his eyes. Many of the cuts on his face and neck required stitches. Shards of glass remain in the safety glasses even today.
Glass Flask Ruptures, Possibly Overpressurization by Liquid Nitrogen
A 250 ml glass flask became overpressurized and burst, spraying two laboratory workers with shards of glass.
Approximately 10 grams of styrene and a minute quantity of a drying agent were immersed in liquid nitrogen to keep the contents frozen. The laboratory worker then attached the flask to a vacuum pump to evacuate the flask, without success. Thinking the flask might have developed a crack, the laboratory worker removed the flask from the vacuum line and was defrosting it under warm water in the sink, holding it and examining it, when the flask ruptured.
The best guess as to the cause of the rupture is that a small leak, perhaps a pinhole in the flask, developed while it was being frozen and that some liquid nitrogen entered the flask. When the flask was warmed, the liquid nitrogen vaporized (expansion ratio 696:1), overpressurizing the flask and leading to the explosion.
The laboratory worker holding the flask suffered from several lacerations to the face, hands, chest and abdomen. The other worker, who was standing across the room, received lacerations to the abdomen. The worker holding the flask noted shards of glass embedded in his prescription safety glasses.
The procedure was re-written such that under the same conditions, the
stopcock will be unscrewed and the flask set in a catchbucket in the
hood to allow the contents to warm up and vaporize, if volatile.
A graduate student sitting at a lab computer was surprised by a chemical waste bottle which burst and sprayed nitric acid and shards of glass all over the lab.
Approximately 2L of nitric acid waste had been accumulated in a chemical waste bottle which originally contained methanol. Over the course of 12-16 hours, it is likely that some residual methanol reacted with the nitric acid waste and created enough carbon dioxide to overpressurize the container. Two other waste containers in the hood were severely damaged and several others were cracked or leaking.
Fortunately, the laboratory worker was not injured.
Incidents Involving Reactive Materials (top)
A laboratory worker attempted to use some anhydrous ethyl ether in a rotary evaporator extraction. The four-liter container of ether was nearly empty. While pouring the ether into the apparatus (inside a fume hood), he noticed that the liquid was oily and had a strange odor, so he decided not to use it. He poured the ether back into the can and went home.
The next morning, he noticed a white residue inside the rotary evaporator. He used a metal spatula to scrape the residue from a glass joint, causing a detonation that shattered the glassware. The flying glass caused severe lacerations to the worker’s hands, face, ear and scalp. Fortunately, he was wearing safety glasses that protected his eyes from injury. Shards of glass were embedded in the lenses of the safety glasses. The sash of the hood was cracked and the light fixture inside the hood shattered.
The can of ethyl ether was purchased 30 months before the incident
and was likely opened about six months later. The container label clearly
warned about the formation of peroxide in storage, despite the presence
of a stabilizer.
A laboratory worker was attempting to distill tetrahydrofuran (THF) using lithium aluminum hydride (LAH). THF is a highly flammable liquid that can cause severe eye irritation and central nervous system depression. LAH is a water-reactive, flammable solid.
The laboratory worker was slowly pouring approximately 1 gram of LAH from a plastic bag into a flask containing 500 ml of THF inside a fume hood. A small amount of LAH leaked from a small hole in the bag, onto the surface of the hood and burst into flames, startling the worker and causing him to drop the remainder of the bag (8-10 grams of LAH) onto the fire. Concerned about the flask and bottle of THF inside the hood, the worker immediately removed his lab coat and placed it onto the fire in an attempt to smother it.
Since the appropriate extinguishing agent was not available, .the worker pulled the flaming lab coat and LAH out of the hood onto the floor. Once the LAH fire had burned itself out, the worker used a dry chemical extinguisher to put out the coat fire.
Since the incident, Met-L-X extinguishers were mounted inside the door
of the laboratory. The laboratory worker keeps a supply of sand (in
a plastic milk jug with the top cut off) on the floor at the side of
the hood where this work is done.
Potassium Metal Released from Pressurized Container
A laboratory worker received burns to one hand when small pieces of potassium metal shot out of an alkali jet apparatus when the laboratory worker opened it for cleaning. The accident occurred because the worker accidentally opened the apparatus while the system was still under pressure. The burn was exacerbated by the fact that the worker rinsed the hand with a small amount of mineral oil rather than with copious amounts of water.
To avoid a future occurrence, the worker installed a venting valve
with a filter to allow venting prior to opening the device. In addition,
plexiglas shielding is placed around the apparatus and the workers wear
gloves, safety glasses and a face shield when opening the device.
Electrical Shock from Laser Power Supply
A laboratory worker noticed condensation on the high voltage power supply for a high powered laser. With the power still on, he wiped the moisture with a tissue, making contact with the exposed anode terminal at approximately 17,000 volts DC to ground.
He received a severe electrical shock and second degree burns to his right thumb and abdomen. Witnesses stated that they heard a loud "snap" and then heard the laboratory worker scream and stagger out to the hallway. He was immediately met by a secretary, and told her "I got a shock" as he collapsed into her arms and onto the floor. He had no pulse and was not breathing. Public Safety officers were nearby and immediately started CPR. The ambulance crew arrived and was able to restore his heartbeat using a defibrillator.
Fortunately, the laboratory worker lived to tell his story. He said
that he knew that the power was on but was not aware that contact was
possible at the high voltage terminals. The interlocks had been defeated
and guards removed with no alternate guarding or precautions taken.
Electrical Shock from Electrophoresis Unit
A laboratory worker received a potentially fatal electrical shock when he accidentally touched a high voltage electrical connector on an electrophoresis device. The contact points were on the right elbow and right knee. Had one of the contacts been on the opposite side of the body, the shock could have been fatal.
The primary cause of this incident was the existence of an exposed
high voltage conductor in the form of a stackable banana plug at the
device. When connected to the male plug on the device, the male connector
plug was left exposed with no insulation or guarding.
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