Which of the following was identified as the cause of the T2 Laboratories incident?

• A. The reactor jacket cooling water supply failed
• B. The wrong chemicals were combined in the reactor
• C. The cooling system lacked design redundancy
• D. The facility owners and operators were unaware of all of the potential hazards associated with the chemical reactions

Answer: (A)

The key idea here is that removing heat is essential to keep an exothermic reaction under control. A reactor jacket is used to transfer heat away; when the cooling water supply fails, heat cannot be removed effectively. The reaction then runs hotter, increasing its rate and generating more heat in a positive feedback loop—leading to thermal runaway, high pressure, and ultimately an explosion. In this incident, the cooling-water supply failure was identified as the trigger that allowed the hazardous reaction to escalate, which is why it’s the best answer. While other issues like mis-mixing, lack of cooling-system redundancy, or unfamiliarity with hazards are serious risks in general, they were not identified as the root cause in this case.