Runaway Reaction Overwhelms the Relief System

A vessel holds a reactive mixture. A skipped step, wrong concentration, or lost cooling starts a runaway decomposition making heat and gas faster and faster. Even a correctly working relief valve can't vent fast enough for a full runaway, and the vessel bursts.

Bayer CropScience (2008) proved it: a runaway decomposition overwhelmed the relief system and burst a 4,500-gallon residue treater — 2 killed, 8 injured; DIERS/API two-phase methods exist precisely because a valve sized for a normal upset can be hopelessly undersized for a runaway. / ([CSB…

1. A trigger occurs — bad charge, defeated interlock, or lost cooling — in a reactor/treater with self-heating inventory.
2. An Arrhenius-style feedback begins: heat and gas generation grow with temperature, which grows with heat.
3. Pressure accelerates; the PSV lifts but generation exceeds relief capacity.
4. Past the tipping point, generation wins and the vessel ruptures.
5. Trainee must detect the acceleration early and quench/inhibit, restore cooling, or emergency-dump before the relief-limited threshold.

CSB documented 167 serious reactive incidents in the US between January 1980 and June 2001 (~8/year serious) causing 108 deaths; 35% were runaway reactions and 70% occurred in chemical manufacturing ([CSB reactive hazards data…

Bayer CropScience: vessel rupture and explosion — 2 killed, 8 injured; reactive incidents in the CSB study produced fires/explosions in 42% of cases and toxic emissions in 37%. ([CSB](https://www.csb.gov/bayer-cropscience-pesticide-waste-tank-explosion/),…