2. June 17, 2014
Fifth yr grad student was on his way thru lab (from his
office to the hall) when he stopped to adjust a
thermometer. Before he touched it, his set-up
exploded. He was not wearing PPE, and he suffered 2nd
degree burns and wounds from glass shards, plus an
injured eardrum. The blast broke all sides of the fume
hood, damaged the neighboring hood and broke an
exterior window.
His set up involved the synthesis of trimethylsilyl azide and suspected contributors to the
explosion include a larger scale (2.5x previously published procedures) and a change of solvent
(from diethylene glycol dimethyl ether to polyethylene glycol, PEG, which may have introduced
water thus producing hydrazoic acid).
University reps concluded that the incident originated in lack of hazard awareness. “It was not
a case of blowing off safety,” says Anna Sitek, research safety specialist in UMN’s EH&S. “They
thought they were making the right changes, but they didn’t know the questions to ask to
recognize when they were moving in the wrong direction.”
4. Start with a What-If Analysis :
• Consult
experienced
researchers
• Reflect on possible hazards including:
• Human error
• Equipment Error
• Process Deviations
5. Assign Probability and Severity Values
to each Hazard:
Risk Rating = Probability x Severity
Probability Rating
0% 0
1-10% 1
11-50% 2
51-90% 3
91-100% 4
Severity Rating
No Risk 1
Minor 5
Moderate 10
High 20