Self-reactive substances that possess explosive properties that, when packaged, neither detonate nor deflagrate rapidly, but are liable to undergo a thermal explosion are classified as which Type?

• A. Type B Self-Reactive
• B. Type C Self-Reactive
• C. Type D Self-Reactive
• D. Type A Self-Reactive

Answer: (A)

The essential idea is how self-reactive substances respond to heat and confinement. These materials can undergo dangerous, exothermic changes if heated. They’re grouped by behavior under heat: the category described here includes substances that have explosive properties but, when packaged, do not detonate or burn rapidly; they are capable of a thermal explosion if subjected to heat. In other words, a runaway decomposition under confinement can lead to an explosion. That’s exactly the behavior of the first category in this self-reactive classification. The other categories describe materials that detonate or deflagrate rapidly, or that decompose without producing a thermal explosion under the same conditions, so they don’t fit this scenario.