What are typical indicators of a reactivity hazard in a process line?

• A. No visible signs are typically observed.
• B. Rapid temperature rise, gas formation, pressure increase, or off-odors.
• C. Only color change indicates hazard.
• D. Decrease in pressure is a hazard indicator.

Answer: (B)

Reactivity hazards show themselves through signs that a chemical change is happening and could escalate. The most reliable indicators are a rapid rise in temperature, formation of gases, increasing pressure, and off-odors. A quick temperature uptick points to an exothermic reaction accelerating, which can lead to a runaway if cooling or containment isn’t adequate. Gas formation means reactive species are generating gas, which raises pressure and can overwhelm venting or containment. An overall pressure rise directly signals that gas generation or vaporization is occurring, flagging a potential overpressure hazard. Off-odors raise a warning that new or decomposed, possibly hazardous, compounds are being formed. Color change alone isn’t a dependable sign because many reactions don’t alter color, and relying on it can miss other critical indicators. A decrease in pressure isn’t a typical early warning of a reactivity hazard, since hazards are usually tied to energy release and pressure buildup rather than loss of pressure.