LA PORTE, Texas (AP) -- U.S. regulators on Thursday took DuPont to task for a massive gas leak last year that killed four workers at a plant in Texas, placing the chemical company in its "severe violator enforcement program" and saying the accident shows it has a "failed safety program."
The Department of Labor's Occupational Safety and Health Administration said the deaths were preventable and revealed hazards that undermine the company's claims of a world-class safety culture.
The agency had previously cited the company for 11 safety violations related to the November deaths at the La Porte plant and on Thursday announced an additional eight offenses, including three "willful" violations. The agency has proposed penalties of $273,000 for the new violations.
OSHA also placed the Wilmington, Delaware-based company in a program that scrutinizes employers that show "indifference" to creating a safe workplace. The decision means DuPont's La Porte plant will be subject to follow-up inspections to ensure compliance with the law, federal officials say.
DuPont "markets its safety expertise to other employers, but these four preventable workplace deaths and the very serious hazards we uncovered at this facility are evidence of a failed safety program," David Michaels, assistant secretary of labor for occupational safety and health, said in a statement from the agency.
DuPont has contested the violations and said in a statement that safety "is a core value and a constant priority." It also was cited for similar safety-management violations last year at a plant in Darrow, Louisiana, and another near Pennsville Township, New Jersey, according to inspectors.
The La Porte plant, southeast of Houston, employs more than 300 workers who make pesticides and other chemicals.
Inspectors found the plant had a faulty ventilation system that exposed workers to a highly toxic and flammable chemical typically used in insecticides. The plant's vents system had several links to the supply line for the chemical, methyl mercaptan.
Liquid routinely built up inside the building's vents due to the system's flawed design, requiring workers to drain the system manually and potentially exposing them to whatever chemicals had accumulated inside, the U.S. Chemical Safety Board said in February.
Even if ventilation system fans had been working, the building's design may not have protected workers from the chemical being released into the air.
DuPont said more than 23,000 pounds of methyl mercaptan were released during the Nov. 15 accident. At dangerous levels of exposure, the gas depresses the central nervous system and affects the respiratory center, producing death by respiratory paralysis, according to OSHA.
DuPont said in a statement that it has resolved nearly all the problems cited by OSHA.
"We have not had a chance to review OSHA's findings in detail; we will work with the agency to better understand the citations and any further required abatement," the statement said. "Operating the La Porte site safely is our number one priority."