ELF ATOCHEM NORTH AMERICA, INC.

One employee killed, 2 injured in stripper vessel explosion

The employer is a manufacturer of epoxidized soybean oil that is used to make fl exible plastic from refined soybean oil. Food grade vegetable oil is fused with hydrogen peroxide, resulting in epoxidized oil. After the main reaction process, the product goes to a vacuum vessel centrifuge. Oil from the centrifuge then mo ves to a stripper vessel where steam removes water, acetic acid, and hydrogen pe roxide product remnants. The steam from the stripper is injected using a vacuum and, in turn, condenses back into a receiving pot after it has moved to an overh ead condenser or heat exchanger/converter located above the stripper. From this condenser, residual acids are stripped out and moved to the acid receiver, a neu tralization tank and recovery site for acetic acid residue. An acidic water line goes from the condenser/ converter to the receiver. Employee #3 and a coworker were checking steam traps on the first floor by tapping on them, but they were n ot removing any of the condensate. They got two new traps ready as replacements after a batch in the vessel was processed. Condensate was drained out of the ste am lines and after the drain valves were closed, the traps were apparently worki ng and the stripper vessel's temperature began to rise to its set point. Employe es #1 and #2 went to the second floor to check the stripper. Employee #2 was loo king through a sightglass atop the stripper to ensure that excessive water was n ot coming in and to check what was happening in the stripper. All appeared norma l when suddenly the acidic water line near the ceiling, which contained water, a cetic acid, and hydrogen peroxide, exploded, blowing out the second story wall. Employee #1 was found dead on an adjacent roof area. He had been walking toward the receiver area near the south wall to turn on the steam valves, but it is not known if he had reached them before the explosion occurred. Employee #2 was abo ut 20 ft away looking into the stripper sightglass; he was struck by flying debr is and exposed to excessive noise. Employee #3, who was walking 8 ft away from t he bottom portion of the stripper on the first floor below, also suffered injuri es from flying debris. Both were hospitalized.