The student injured his arm and side, and he needed surgery to deal with glass shards, chemistry department chair William B. Tolman said yesterday afternoon. The student also injured an eardrum. He was not severely burned. “He was lucky,” Tolman said. “It was a pretty powerful explosion.” Tolman expected the student to be hospitalized for another couple of days.
Investigators have not spoken with the student yet, and they don’t know how much material he was working with or at what point he was at in the process, Tolman said. The location of the student’s injuries indicates that he was reaching into the hood when the explosion happened, but what he was reaching for or why remains unknown. Tolman also didn’t know what protective equipment the student was wearing or whether he was using a blast shield.
As for why the explosion happened, “I have a lot of ideas and no evidence for any one of them,” Tolman said. Humid weather could have led to moisture in the system and production of hydrazoic acid, for example, or something could have set off the sodium azide starting material.
“I have concerns over the level of recognition of hazard and risk mitigation, but I don’t know enough yet about what exactly was done and not done,” Tolman said.
The department has been working over the past couple of years to improve its safety culture. Given all the unknowns about the incident, it’s too early to say whether the efforts helped to mitigate what happened or what more the department might want to do, Tolman said. At the same time, “I will say that we are in a particularly good position to learn well because we already have a strong communications effort in place,” he added.
More discussion at Chemjobber
Updated to add photo
Updated again to add: More details on the University of Minnesota explosion and response