GEISMAR - The U. S. Department of Labor fined Williams Olefins LLC on Wednesday for safety violations they said contributed to a June plant explosion which killed two workers and injured 80 in Geismar.

The Occupational Safety and Health Administration issued the $99,000 fine after citing the company for six safety violations. One of them included a "willful" violation for not creating clear procedures for how to get idle pressure vessels ready for service.

According to OSHA, a willful violation is one committed "with intentional, knowing or voluntary disregard for the law's requirements, or with plain indifference to worker safety and health."

The June 13 explosion killed Zachary Green, 29, and Scott Thrower, 47, who were among the 127 people working at the Geismar propylene plant. Plant operators said the explosion happened after a reboiler ruptured, igniting a vapor cloud.

"It is the employer's responsibility to find and fix workplace safety violations and to ensure the safety of its workers," said Dorinda Folse, OSHA's area director in Baton Rouge. "Failing to do so cost two workers their lives."

The company has 15 days to respond to the fines, either by paying or contesting them. A company spokesperson said they were continuing with their own internal investigation.

"Williams cooperated in a full and transparent manner to support OSHA's investigation, and we are in the process of reviewing the analysis," said John Dearborn, senior vice president, NGL and Petchem Services.