Shelf Collapse leads to a spill and a spill/explosion at separate institutions
Key Instruction Points
- Do not procrastinate at getting broken equipment repaired.
- Follow your institution's safety procedures.
- Treat spill clean-up materials as hazardous waste.
The collapse of a shelf in a flammable storage cabinet lead to an explosion and fire in a lab at X causing the destruction of two labs and damage ranging from $200,000 to 300,000 in repairs. Spills due to the unstable shelf had occurred previously but no one had tried to repair or replace the defective shelf. In this instance,12 containers of hexane were being unpacked into a flammable storage cabinet when one of the shelves collapsed. The resulting three-alarm blaze took about 20 fire trucks and 84 firefighters from several area fire stations more than an hour to extinguish.
Flammable liquids ignite when there is enough fuel and oxygen in the air to support a flame, as well as an ignition source. Common ignition sources in labs are Bunsen burners and stirrers with brush-type motors. Plugged-in electrical equipment could also be an ignition source. In this case it was never determined what the ignition source was.
There were about 50 gallons of flammables in the lab which lead firefighters to switch from water to dry powder extinguisher, and finally to chemical foam, which eventually put out the blaze.
In a completely separate incident at another institution, a spill occurred when a shelf located in a flammable storage cabinet under a chemical hood, collapsed. A gallon bottle of glycerol and a gallon bottle of isopropyl alcohol broke and spilled. Additionally, a gallon bottle of acetone had fallen off the shelf and was leaking. Rather than vacating the room and contacting the safety office to clean-up the spill lab personnel cleaned up the spill themselves which took about 30 minutes. The personnel recently attended training where emergency procedures were reviewed. They used a broom, a dustpan, and brush to pick up the broken glass and the liquid. They placed the entire contents of the spill, including the liquid, in a box designed for broken glass on the floor of the lab where it continued to evaporate over the weekend.
It is believed that improperly installed shelving clips caused the shelf to collapse. This was a new lab and the solvent cabinet was being used for the first time. An inspection of all the shelves in the area found other clips that were also not installed properly.
The personnel involved in incident did not follow the institution’s emergency procedures which had been reviewed during training and which are listed in a emergency flip chart which is posted in the lab. Lab personnel are responsible for cleaning up minor chemical spills, only. A minor chemical spill is defined as = 1 liter of any chemical that is NOT a carcinogen, acutely toxic or a reproductive hazard. The safety office and other emergency response personnel handle all other chemical spills. Everybody should have left the room and someone should have called for help from a location where the safety office could call back to get information about the spill.
Besides posing a fire hazard (vapors from flammable liquids catch on fire, not the liquids themselves), they violated their institutions policies as well as EPA regulations regarding hazardous waste. It is against federal environmental regulations to evaporate chemical waste into the atmosphere.
Carbon Disulfide Fire
Key Instruction Points
- Store liquids in stable containers or use racks.
- Recognize location of nearest ignition sources when using flammable liquids
We have four gas chromatographs (GCs) on two sides of one ten-foot-long aisle of our laboratory. One of our analysts was working at one of the GCs and was choked by a cloud of some sort of gas of an unknown origin and nature. After looking around for a second or two and not finding the source, she called out for everyone to get out of the lab and set off the fire alarm in the hallway, waiting for the Fire Department HazMat team and finally our own staff to identify what the problem was.
What we finally discovered was the following: another analyst in our lab, a contractor, had set an open vial (with an inward-tapered opening at the top) of carbon disulfide, used for flushing GC autosamplers, on top of another GC across the aisle. Somehow, the vial tipped over and rolled into the opening at the top of the GC where the heated injector is located. Presumably the CS2 heated up the vial when it came into contact with the injector, and sprayed out CS2 vapor. The vapor burst into flame (because of the very low auto-ignition temperature) when it came in contact with the injector, producing a nearly-suffocating cloud of SO2 and unburnt CS2 which passed over the other analyst, moving in the direction of the nearby fume hood. The entire incident was over in perhaps 10 seconds (but we didn't know that at the time)!
The analyst who breathed the combustion products was checked and found to have suffered no ill effects. The GC where the fire took place has a few scorch marks around the injector, but otherwise suffered no damage. The lost time of the several hundred people that work in our 7 story building and were kept outside for about 2.5 hours was significant.
The primary cause of the incident was putting a narrow-based vial with a highly flammable solvent on top of an instrument.
We put a stop to the practice of putting things on the top of Gcs immediately. After the incident we had the carpentry shop fabricate a half dozen small tube racks that will hold GC vials of the appropriate size. There is one such rack next to every GC in the lab now. We have established a rule that nothing will be put on top of any GC - or any other instrument - but only in a rack, on the bench top.
We were fortunate that we had no injuries or property damage, but the cost in lost time to ourselves and others in our building was significant.
Fire From Diethyl Ether Spill
Key Instruction Points
- Wear long pants and shoes in the lab.
- Work at least 6" inside the chemical hood.
A graduate student was injured by flash fire due to a reaction product hat contained about 1 liter of ether. The ether was to be filtered through a cup shaped device containing the desiccant sodium sulfate. The filter apparatus was placed in a 2 liter round bottom flask and connected to house vacuum. The round bottom flask was attached to a ring stand.
The 2-liter Erlenmeyer flask that containing the diethyl ether and reaction product broke and spilled into the hood and onto the floor in front of the hood. The whole assembly was situated at the front of the fume hood on the sill adjacent to the fume hood airfoil so when the container broke the flammable mixture was not contained in the hood. In addition, the sash on the hood was fully open.
Seconds later, a fire rising from the floor in front of the fume hood engulfed the student. The source of ignition was most likely a drying oven that was situated under the hood. Unfortunately the student was wearing shorts and sandals. The student moved away from the fume hood and rolled on the floor to extinguish the flames. A nearby safety shower was blocked by equipment.
The student was able to leave the building with help from colleagues where he waited for emergency response. After initial treatment by fire department technicians, an ambulance arrived and transported him to a regional burn treatment center.
There was no written standard operating procedure and apparently this was an elementary procedure that the student had performed thousands of times. The lab manager had performed and reviewed the procedure with the student but the procedure was not documented in the students notebook or in the Laboratory Safety Plan. The student had recently attended a general department training program.
During the two years prior to the fire, the lab had undergone three safety inspections. The inspection reports documented many deficiencies in procedure and had noted the extremely crowded laboratory conditions. The PI had not responded to the reports.
Several steps could have been taken to prevent or mitigate incidents:
- Check glassware before using it for cracks or scratches. Replace damaged glassware.
- Use plastic coated glassware for transporting or holding solvents. When glassware is replaced, order some of the break resistant glassware.
- Allow more space for workers. There were at times as many as 14 people in the lab
- Work at least 6 inches inside the chemical hood. This is critical for containment of vapors. In addition, the work top on the chemical hood is dished and will contain a spill.
- Work with the chemical hood sash pulled down to shoulder height. The sash can protect the workers face and breathing zone from a deflagration and can greatly reduce exposure to gases and vapors in the hood. With the sash at this height, a hood may contain a fire.
- Do not block safety equipment such as the safety shower.
- Do not house drying ovens under chemical hoods.
- Require lab personnel to wear long pants and shoes in the laboratory. Prohibit shorts and sandals. In addition, goggles and lab coats should be required for procedures involving large quantities of hazardous liquids.
Training must be documented for new workers and annually thereafter. Require training for all personnel working in the laboratory. Assure that laboratory workers document safe procedures in their notebooks, send students to the fall departmental training sessions and hold periodic meetings with staff. At lab meetings, include a safety related agenda and file the agenda.
Explosion and fire occurred in a lab in X Hall. A graduate student was thrown four feet and cracked a rib. Her hair was singed from the fire ball. She was heating dioxane, a flammable solvent, and azobisisobutyronitrile on a hot plate in a glove box when a leak was suspected to have developed in the box. The hot plate’s thermostat probably served as the ignition source. She did not have the MSDS for azobisisobutyronitrile and she was unaware that upon heating this chemical produces an acutely toxic chemical, tetramethylsuccinonitrile (TMSN). TMSN is immediately dangerous to life and health (IDLH) at 5 ppm. For comparison, cyanide gas has a IDLH at 25 ppm.
Personnel from the Health and Safety Office entered the room to retrieve coats and open the windows not knowing the presence of this chemical. Their selection of personal protective clothing was insufficient to protect them from the TMSN. Both became ill from exposures.
Description of Incident
The experiment involved heating 300 mL of dioxane, 30 grams of N-isopropylacrylamide, and 6.24 grams of azobisiosobutyronitrile ("VAZO" 64) in an inert atmosphere, on a hot plate. Early in the experiment the student suspected there might be an air leak because the gloves which normally were inflated were sagging. The graduate student spilled approximately 10 mL. Working within the gloves, she wiped up the spill with some paper toweling. Suddenly, with no warning, the reaction exploded and threw her 3 to 4 feet into the bench behind her.
Another student phoned Security and the Environmental Health & Safety office. He evacuated the hallway and all the adjacent labs, grabbing the book of MSDSs before leaving. She informed the Health and Safety Office of only three of the four chemicals that were involved in the incident. The company had never sent her a MSDS for "VAZO". She was visibly shaken and her eyelashes and hair was singed. The Health and Safety Office recommended that she shower, change clothes, and get a medical examination.. The weather was freezing and students were requesting their coats, lap-top computes and other belongings from the affected area. An employee from The Health and Safety Office entered the lab with a half face respirator with organic vapor cartridges to shut down the experiment, retrieve personal items, and open windows. The Health and Safety Office found that many of the windows which had been designed to open were sealed shut. After about 20 minutes, a pane of glass was broken for ventilation.
An emergency response team from ________ was called after several hours to appraise the situation because of the persistent smell. The emergency response team wore Self Contained Breathing Apparatus (SCBA).
Neither student experienced any chemical exposure symptoms, although both were examined by physicians. The student involved in the explosion did crack a rib as a result of her impact with the counter.
The next day the student was interviewed again. She informed the Health and Safety Office of the chemical she neglected to mention the day before. The missing chemical was the azobisiosobutyronitrile or "VAZO" 64. She thought it was causing the residual smell in the room. Researching the chemical, The Health and Safety Office discovered that upon heating the "VAZO" readily converts to Tetramethylsuccinonitrile, an odorless chemical that is highly toxic and can be fatal in very small doses. Concentrations of Tetramethylsuccinonitrile are Immediately Dangerous to Life and Health (IDLH) at 5 ppm. [For reference NIOSH lists Sodium Cyanide, gas, at 25 ppm., both by inhalation.] Both health and safety office personnel who had entered the room experienced temporary symptoms from exposure to the Tetramethylsuccinonitrile that had penetrated their cartridges.
The heating of flammable solvents should be done so as to avoid any contact with ignition sources. An explosion proof hot plate is recommended for future experiments. The glove box is unsuitable for the use of flammable liquids due to the factory installed electrical outlets. Due to the air leak, all the elements were present for the fire ball that resulted. Students should have researched each of the reactants and had a thorough understanding of their properties and decomposition products.
The Health and Safety Office should not have entered an area that has an unknown atmosphere.
Students possession should never have been taken from the room without being decontaminated. These items were collected for cleaning.
In the future, an explosion proof hot-plate and a non-electric balance should be used.
The glove box manufacturer should be contacted and asked if the box is acceptable for use with flammable solvents.
A written standard operating procedure (SOP), that includes safety procedures, should be developed. The SOP should demonstrate a thorough understanding of all chemicals involved. SOPs should be reviewed by students and supervisors.
Provide closer supervision of graduate students.
After incidents similar to this one the contents of the room should stay undisturbed until a thorough evaluation is completed.
No chemical should be used until the MSDS is obtained and reviewed.
Lithium Aluminum Hydride Fire
Key Instruction Points:
- Know the hazards of the materials, including appropriate extinguishing agents, before using chemicals.
- Carbon dioxide reacts with LAH explosively; thus, a carbon dioxide extinguisher could have made the situation worse. A Met-L-X fire extinguisher (for flammable solids) or dry sand should have been immediately available.
- Do not pour solids such as LAH directly from the container into another chemical or reaction vessel. Measure out what is needed, then pour it.
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.
Sodium Hydride Fire
Key Instruction Points:
- Fires involving reactive chemicals may not be extinguishable by the carbon dioxide (BC) or dry chemical (ABC) extinguishers typically provided to laboratories. If water reactive chemicals are used or stored in the laboratory, consider keeping a small amount of sand or limestone on hand.
- Consult the manufacturer’s Material Safety Data Sheets for the recommended type of extinguisher for these materials.
- The fume hoods in many of the newer laboratory buildings are sprinklered. Sprinkler activation during a fire will exacerbate the situation when a water reactive chemical is involved. It is best to let this type of fire burn itself out rather than attempting to fight it yourself. Lower the sash if possible, leave the area, and activate the building fire alarm. Call your institution’s emergency phone number from a safe location and provide details about the fire.
Sodium hydride (NaH) can react with water or spontaneously with moist air to generate highly flammable hydrogen gas and corrosive sodium hydroxide. A few months ago, a graduate student was attempting to convert some unneeded NaH into a less reactive compound, a process known as quenching, prior to disposing it. The reaction was conducted in an ice bath and when the extreme heat liberated by the process ruptured the reaction beaker, a brief, though very intense fire occurred. Fortunately, no one was injured.
This accident provides a backdrop for considering the following points about procedures for hazardous waste disposal, fire safety, and working with chemicals posing particular hazards.
Many chemicals used in the laboratory, including NaH, are legally considered regulated hazardous waste once they are designated for disposal. Many Research Institutions are not licensed to treat (e.g., quench) such waste on site. Contact your safety office to arrange for the safe and legal disposal of hazardous chemicals through your institution’s hazardous waste vendor.
Solvent Explosion and Fire
At the University of X, a 55 gallon drum containing 30 gallons of mixed organic solvents exploded, launching upward into the ceiling, within the hazardous waste storage facility and began a significant fire. Luckily, no one was hurt. The mixed organic solvents in the drum had been consolidated from solvent waste containers from laboratories across the campus. A similar consolidation process is used at many research institutions.. Solvents are consolidated because there is significant cost savings in disposing of one large drum as opposed to many smaller containers. This incident demonstrates how important it is for each lab to fully report the contents on each container on the hazardous waste label.
Letter from a Post Doc Burned in a Solvent Fire
The author of the following letter is a former University of X graduate student now working as a post-doc at another institution. It was forwarded to the Health and Safety Office by one of his former colleagues. Identifying information including the names of the people involved and the name of the institution where the incident occurred have been changed.
I've been trying to email you for some time but the computer wouldn't let me through for some reason - hope we have better luck now. I wanted to tell you some news in the meantime - I was in a serious lab accident here in John’s lab and was quite badly hurt. Before I relate the rest of the tale (it is quite frightening) let me assure you that I am basically OK, I'm not disabled or horribly disfigured or anything.
What happened is a there was an explosion and fire in the lab in which I was actually set on fire and badly burned. Friday afternoon September 11th. This ?#%&* lab technician was working at her bench with a burner going full blast; John and I were standing about 6 feet away. She proceeded to pour from a full one gallon glass bottle of methanol with the mouth of the bottle only a few inches from the flame. John and I stared in horror at the stupidity of the action; I took a few steps toward her as I told her to stop what she was doing and get the bottle away from the flame ASAP, about to give her the safety lecture of her life.
The whole thing exploded in my face; all I saw was a ball of blue flame as the entire bay was drenched with burning methanol. It was like I was hit by a flamethrower - I looked down and flames were coming from my chest and arms. The whole episode only lasted for 5 or 10 seconds before I got under the emergency shower (thanks to cool thinking by Sam Smith who basically saved my life). I was burned over about 20% of my body surface - a mixture of 1st, 2nd, and 3rd degree burns on my chest, left side, left arm and hand, right forearm, the front of my neck, and the bottom half of my face. The sprinkler system extinguished the rest of the fire. No one else was hurt - the person who was responsible left the next day for another position so I couldn't even have the pleasure of firing her.
I spent 10 days in the Hospital Intensive Care Unit, and had skin graft surgery to repair the worst of the burns. There are whole days of my time in the ICU that I have no recollection of, but what I remember was a nightmare.
But in the end I walked out of the hospital on my own two feet. The good news is the burns to my face and neck were very superficial so they healed up nicely and I'll have no scarring there - with a long sleeved shirt on you'd never know anything had happened to me (in fact I look even better after the accident - the facial burn was like having a chemical face peel, and I lost around 15 pounds in the hospital plus I have a new spiky punk haircut from when the ICU nurse cut away all of my burned hair, so people at first think I went to a spa or something). My chest and left arm are a different story - I'll definitely have some scarring there but its too early to tell what it will look like. Considering how easily I could be dead/blind/horribly disfigured I consider myself very, very lucky indeed. Five weeks after the accident I was back in the lab at work.
So now I preach lab safety to everyone I talk to. Tell your people to be careful with flammable solvents and remember what I learned the hard way - it doesn't matter how careful you are, someone else's stupidity can get you killed.