Which of the following should be included when looking for locations and situations where chemical reactivity hazards may present themselves?

• A. Primary or intended reactions
• B. Locations where equipment is exposed to direct sunlight
• C. Potential unintended reactions (such as polymerization or decomposition)
• D. Reactions resulting from inadvertent mixing of incompatible materials (including waste streams)

Answer: (A)

Focusing on the primary or intended reactions is the starting point for identifying where reactivity hazards may occur because this defines the actual chemistry the facility is designed to perform. Knowing what reactants come together, under what conditions, and in what sequence tells you the real energy changes, potential heat buildup, gas evolution, and formation of reactive intermediates that drive the major hazards. With this foundation, you can size and specify controls like cooling, quenching, containment, and venting to prevent runaway or releases. Other factors, such as exposure to sunlight, can matter for specific photochemical cases, but they are not the general basis for locating reactivity hazards across a process. Potential unintended reactions and inadvertent mixing are important to consider, but they’re better addressed once the primary reaction and its operating envelope are understood.