Abstract: At approximately 2:35 p.m. on April 1, 1986, an employee noticed product liquor leaking from a 20,000 gallon fiberglass chemical holding tank outside of the sulfur building. He notified plant maintenance. Employee #1 and a coworker joined him at tank #1, where they decided to close the valve to isolate it from connected tank #2. After closing the valve, the employee who had discovered the leak went directly to the pulp mill to discuss how to pump out tank #1, leaving Employee #1 and the other coworker at the site. In the approximately two minutes it took him to reach the pulp mill, the 20 in. manhole assembly on tank #1 gave way, splashing Employee #1 and engulfing him in a cloud of gas. The coworker pulled him out of the area to a chemical building about 100 ft east of the tanks, where he soaked Employee #1 with water from a hose. They were forced to evacuate that area due to a cloud of mist. Employee #1 collapsed as they tried to reach the pulp mill, where he died. Cause of death was pulmonary edema from inhaling a chemical mist of sulfur dioxide or sulfuric acid. Employee #1 also suffered chemical burns over 90 percent of his body.