Chemical producer Williams could be fined as much as a $99,000 by the U.S. Occupational Safety and Hazard Administration (OSHA) in connection with an explosion of a propylene fractionator at its Geismar, Louisiana, site last summer.

The agency said it had found six violations of process safety management in the June blast that killed two people and injured 80. It termed one of the violations "willful," meaning that the company failed to develop clear, written procedures for how to change and put idle pressure vessels into service. Five other violations were rated as "serious."

At the time of the incident, the plant was in a turnaround to add capacity for ethylene and polymer grade propylene. Williams said the upgraded facility will be restarted in April with a capacity of 885,000 t/y of ethylene, up from 612,000 t/y previously.

The company and the U.S. Chemical Safety Board are conducting their own evaluations of the causes of the explosion, parallel to the probe by OSHA. The occupational safety board said Williams "cooperated in the investigation in a "full and transparent manner."