More discussion on the U Minnesota azide explosion

Credit: National Institute for Occupational Safety & Health

Credit: National Institute for Occupational Safety & Health

We’ve had blog post the first (“Explosion injures…”) and blog post the second (“More details…”), plus a C&EN safety letter and “C&EN Talks Safety with William B. Tolman.” A reader responds in this week’s issue:

I was disappointed by the lengthy chemical safety letter from T. Andrew Taton and Walter E. Partlo on the azidotrimethylsilane explosion in Taton’s lab (C&EN, Oct. 27, page 2). Lacking was the admission that Partlo, a fifth-year graduate student, was not wearing any personal protection at the time of the incident.

Their concluding recommendations also omit any mention of having used personal protective equipment. Where is the recommendation for the use of a blast shield?

A blast shield provides an additional layer of protection for the researcher when the hood is opened, especially in cases where the hood is not the vertical multi-sliding-door type but the full horizontal sash type. (See the University of Illinois webpage at

I have never forgotten a coworker’s serious injuries in a Yale University chemistry lab in the 1970s during the distillation of a mere 25 mL of a known hazardous compound.

Why do our academic labs still not take basic precautions when working with such hazards? Why isn’t personal protection the basic standard at all times in our chemistry research labs?

I reference C&EN’s The Safety Zone blog: “He stopped and reached into the hood, but he didn’t have time to touch anything before the experiment exploded, says Anna Sitek, a research safety specialist in UMN’s department of environmental health and safety. Partlo wasn’t wearing any personal protective equipment.”

Katherine E. Flynn
St. Charles, Ill.

While Flynn has a point about the fact that basic personal protective equipment should be standard, it’s worth remembering that PPE comes last on the hierarchy of controls, after elimination, substitution, engineering, and administrative. Both the safety letter and my discussion with Tolman were focused more on those higher-level controls.

Also, over at Chemjobber is some more information about the department’s 5 g limit for reactions involving azide.

Last but not least, the Campus Safety Health & Environment Management Association is holding a webinar on Dec. 3 to discuss hazard evaluation and communicating lessons learned featuring Minnesota chemistry department chair William Tolman, safety officer Anna Sitek, and chemical hygiene officer Jodi Ogilvie. It’s free for CSHEMA members, $130 for nonmembers.

Author: Jyllian Kemsley

Share This Post On

1 Comment

  1. I certainly appreciate the desire to shine a spotlight on the first/top barriers in the hierarchy of controls. However, while PPE may be the last item in the hierarchy, should it really be omitted from the discussion of an incident that involved a lack of PPE? I thought the accepted philosophy was that every barrier should be treated as if it could be the only one. What about Defense in Depth?


  1. TMS Azide Explosions - - […] recently, a letter to C&E News mentions that no one at the university has been talking about blast shields.…