Trimethylsilyldiazomethane safety under investigation

Trimethylsilyldiazomethane, aka (diazomethyl)trimethylsilane

Trimethylsilyldiazomethane, aka (diazomethyl)trimethylsilane

Back in 2008, two chemists died after exposure to trimethylsilyldiazomethane (TMSD): Jason Siddell, age 24 and employed at Gelest, and Roland Daigle, age 46 and employed at Sepracor Canada (now Sunovion Pharmaceuticals Canada). This year, the U.S. National Toxicology Program (NTP) is finally studying the compound’s toxicity.

The U.S. Occupational Safety & Health Administration (OSHA) investigated Siddell’s death. OSHA cited Gelest for violating hazard communication standards and fined the company $1,500. Daigle’s case was investigated by the Nova Scotia Department of Labour & Advanced Education and the province filed five charges against Sepracor Canada. The company agreed to a deal that involved pleading guilty to one charge of failing to provide proper workplace ventilation and a $47,000 fine. A bit more detail about what happened to Daigle can be found in a case report published in Clin. Toxicol. 2009, DOI: 10.1080/15563650903076924 (abstract 48).

U.S. OSHA also nominated TMSD for study by NTP. As Derek Lowe has noted, many people believe TMSD is safer than diazomethane. TMSD is safer if you just consider explosive properties. But toxicologically, TMSD may be just as poisonous as diazomethane. The toxicology studies will say for sure. NTP is part of the National Institute of Environmental Health Sciences, and according to institute spokeswoman Robin Mackar, NTP has developed and validated an inhalation exposure system and plans to start acute toxicity studies in the fall. “The primary focus of these studies is to evaluate potential pulmonary toxicity, but other tissues will be assessed,” Mackar adds. “Once the research and analysis is completed, the results will be published in a peer-reviewed journal publication.”

Author: Jyllian Kemsley

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