Abstract: At approximately 4:15 p.m. on January 21, 1994, Employee #1 engaged in cleaning a single compartment 5,000 gallon tank trailer with a residue of dodecylbenzenesulfonic acid that had been purged with nitrogen. The tank was at Bay 2. He entered the tank in his wash suit, boots, harness, and full face dual cartridge acid gas/organic vapor respirator, and holding a garden hose. He had been trained in company policy that all dirty tanks were permit-required confined spaces. He acted contrary to company policy and entered without a permit, attendant, oxygen meter, winch retriever, or lifeline. Suffering asphyxiation, Employee #1 required hospitalization. He acted independently of company expectations. No T8CCR violations were attributed to the accident.