Abstract: At approximately 3:15 p.m. on October 19, 1994, Employees #1 through #10 and three coworkers were engaged in mechanical repairs and maintenance in and around the alkylation and catalytic hydro-desulfurization units. The employer and the onsite employer removed the lockout/tagout devices from the isolation locations for the 11C-10 coalescer. The onsite employer was putting the coalescer in service when there was a hydrocarbon release which resulted in an explosion and flash fire. Employees #1 through #4, #6, and #7 suffered burns to their faces, arms, and hands. Employees #5 and #7 suffered respiratory distress. Employees #9 and #10 and the three coworkers sustained various injuries, including cuts, back problems, and a head injury. All the employees were hospitalized for treatment.