A few days before the Chemical Safety Board report on Texas Tech University came out, TTU had another laboratory explosion of sorts in the chemistry department. This one didn’t involve energetic materials; rather, it centered on a waste bottle that contained dilute nitric acid, TTU Vice President for Research Taylor Eighmy said in a conference call for reporters last week. The nitric acid bottle was in a hood, next to a bottle of dilute acetic acid, and when the nitric acid bottle blew it cracked the base of the hood and sent glass shards and the waste solution into the lab, TTU said.
The good news was that the lab was empty and no one was hurt. But someone could have been hurt because the hood sash was up–although I don’t know how high–and the glass and waste solution was therefore able to spread out into the lab, Eighmy said. So that’s lesson #1: Pull down hood sashes.
Lesson #2 will likely involve what exactly was in the bottle with the nitric acid. TTU is still investigating that. But, as we saw last month at the University of Maryland and others have noted, nitric acid is a strong oxidizing agent and will react with organic compounds. Prudent Practices has this to say about it (page 138):
Nitric acid is a strong acid, very corrosive, and decomposes to produce nitrogen oxides. The fumes are very irritating, and inhalation may cause pulmonary edema. Nitric acid is also a powerful oxidant and reacts violently, sometimes explosively [with] reducing agents (e.g., organic compounds) with liberation of toxic nitrogen oxides. Contact with organic matter must be avoided. Extreme caution must be taken when cleaning glassware contaminated with organic solvents or material with nitric acid. Toxic fumes of NOx are generated and explosion may occur.
This week, there was a fire in a medical research lab at the University of California, Los Angeles, Center for Health Sciences. It was a small fire that was confined to one room and no one was injured, UCLA said. But nearly 150 fire fighters responded, the Los Angeles Fire Department said. UCLA spokesman Phil Hampton told me in an e-mail that “a confirmed fire in a research lab in a multi-story building automatically generates a large response. The vast majority of the responding crews left shortly after they arrived.” UCLA is still investigating the cause of the fire. The Daily Bruin reported today that:
Lab manager Erika Valore said she was not in the lab at the time but was told a person working there was boiling water in plastic tubes over a Bunsen burner.
Valore said the person left the room for a couple of minutes. Then people in the lab smelled smoke and saw flames going up to the ceiling, she said.
This would not normally happen with a water bath, and the incident was highly unusual, Valore said. She added she had not seen anything like this in her 25 years at UCLA.
I’m not clear from this what, exactly, “would not normally happen with a water bath”: that it was set up with plastic tubes over a Bunsen burner, that it was left unattended, or that it went up in flames? A Bunsen burner is obviously a fire hazard and should not be left unattended (see here for other safety precautions). As for the water bath aspect, it would be unusual for a typical water bath in a glass container to catch fire. Plastic tubes and a Bunsen burner, however, seem like a recipe for a fire.