Abstract: At approximately 10:45 a.m. on October 14, 1991, Employee #1 was repairing a tank trailer. Although the repairs were to be done from the top of a tanker, Employee #1 decided to drain the liquid residue in the tank before repairing it, thinking the liquid was fertilizer. Underneath the tanker trailer, Employee #1 used an impact wrench to unbolt the sump's bottom flange. The plate dropped approximately 2 in., releasing sulfuric acid onto Employee #1. He suffered 3rd-degree burns on a section of his left upper shoulder and back and 2nd-degree burns to his left lower and upper arm. He was hospitalized.