After a series of accidents at plants in the states of Texas, New Jersey, and Louisiana, the US Occupational Safety and Health Administration (OSHA) said it planned to place chemical giant DuPont on the five-year-old Severe Violator Enforcement Program list of problem companies.

OSHA cited the chemical producer’s failures to correct safety violations such as rundown equipment, undertrained workers and undisclosed hazards. Four workers died in the La Porte, Texas, accident, which involved a leak of methyl mercaptam.

In May of this year, the agency proposed fining DuPont $99,000 for violations related to the fatalities at the LaPorte herbicide facility. On Jul. 9 it proposed adding another $273,000 penalties for additional violations found in an inspection in January.

The workplace safety watchdog said DuPont had “demonstrated indifference towards creating a safe and healthy workplace by committing willful or repeated violations, and/or failing to abate known hazards.”

In a statement, OSHA assistant director David Michaels said, “DuPont promotes itself as having a 'world-class safety' culture and even 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.”

In response to OSHA’s recent complaints about LaPorte, DuPont said it had identified and addressed most if not all of the agency’s significant findings.

DuPont was also cited for process safety management violations at its Darrow, Louisiana, facility in November 2014 and at the Deepwater, New Jersey, site in December of the same year. Deepwater now belongs to the company’s Performance Chemicals spin-off Chemours.