I have this from a lab-accidents-I-have-known discussion over on Reddit. It is, of course, unverified, but it's depressingly plausible. As a chemist, this one is guaranteed to make you bury your head in your hands - it's the second law of thermodynamics come to take vengeance, with the entropy increasing as you go along:
"A graduate student was constructing three solvent stills (dichloromethane, THF and toluene) inside a hood in Room XXXX. As a final step in this process, the student was cutting pieces of sodium metal to add to the stills. Once the sodium had been added, the student began to clean the knife used to cut the sodium. During the cleaning, a small particle of sodium was apparently brushed off the knife. The sodium landed in a drop of water/wet spot on the floor of the hood and reacted immediately making a popping sound. The graduate student was startled by this sound and moved away quickly.
In his haste to get away from the reacting sodium, he discarded the knife into a sink on the bench opposite the hood in which he was working.. Apparently, there was another piece of sodium still adhering to the knife since upon being tossed into the sink, a fire ignited in the sink, catching the attention of another student in the lab. As the flames erupted, the student noticed a wash bottle of acetone sitting on the sink ledge nearby. He immediately grabbed it to get it away from the flames, but in the process, squeezed the bottle, which squirted out some acetone which immediately ignited. The student immediately dropped the bottle and began to evacuate the lab. As he turned to leave, he knocked over a five gallon bucket containing an isopropanol/potassium hydroxide bath which also began to burn. This additional fire caused the sprinklers to activate and the fire alarm to sound which in turn resulted in the evacuation of the building.
When the sprinklers activated, water poured into the bulk sodium-under-mineral-oil storage bottle which had been left uncapped in the hood resulting in a violent reaction which shattered the bottle sending more sodium and mineral oil into the sprinkler water stream. This explosion also cracked the hood safety glass into numerous little pieces although it remained structurally intact. By the time the first-responders arrived on the scene, the fire had been extinguished by the sprinklers, but numerous violent popping sounds were still occurring. The first-responders unplugged the electrical cords feeding the heating mantles, shut off the electricity to the room at the breaker panel and waited until the Fire Department arrived. Eventually the popping noises stopped and sprinklers were turned off. The front part of the lab sustained a moderate amount of water damage The hood where the incident began also suffered moderate damage and two of the three still flasks were destroyed. The student, who was wearing shorts at the time of this accident, sustained second and third-degree burns on his leg as a result of the fire involving the isopropanol base bath.
There were some additional injuries incurred by the first-responders who unexpectedly slipped and fell due to the presence of KOH from the bath in the sprinkler water. These injuries were not serious but they do illustrate the need to communicate hazards to first-responders to protect them from unnecessary injury."
I doubt if the sodium was being added to the dichloromethane still; I've always heard that that's asking for carbene trouble. (Back in my solvent-still days, we used calcium hydride for that one). And it would take a good kick to knock over a KOH/isopropanol bath, but no doubt there was some adrenaline involved. I'm also sorry to hear about the burns sustained by the graduate student involved, but this person should really, really have not been wearing shorts, just as no one should in any sort of organic chemistry lab.
But holy cow. The mental picture I have is of Leslie Neilsen in a lab coat, rehearsing a scene for another "Naked Gun" sequel. This is what happens, though, when things go bad in the lab: we've all got enough trouble on our benches and under our fume hoods to send things down the chute very, very quickly under the wrong conditions. And were these ever the wrong conditions.