Abstract: At approximately 10:05 a.m. on January 24, 1992, Employee #1 was pumping 12.5 percent sodium hypochlorite solution into a Flowtrace Inc., cyanide destruct system for waste cyanide. Small levels of cyanide are present in the waste water generated by the building tenants, who are jewelers. This bleach is pumped from a 55 gallon plastic drum by an electric pump and a plastic hose. When the bleach ran dry, Employee #1 obtained a new drum to pump. The second drum contained hydrochloric acid, instead of bleach. It generated vapors of an unknown composition: either hydrogen chloride gas; vapors generated by mixing hydrochloric acid with sodium hypochlorite; or hydrogen cyanide gas from the waste water. Employee #1 left the basement and went to the 11th floor to contact the property manager for help. Employee #1 would not talk to Cal/OSHA; however, the accident report from the paramedics indicated that he suffered chest pains, breathing difficulties and shortness of breath. Employee #1 was hospitalized for 9 days. According to the employer, five drums of bleach and one drum of liquid caustic had been ordered from the Soco Lynch Corp. Hydrochloric acid was delivered by mistake to the employer. Employee #1 had signed the shipping order and accepted the acid, assuming it was bleach.