The U.S. Department of Labor's Occupational Safety and Health Administration recently cited DuPont for 11 safety violations and identified a number of safety upgrades the company must undertake to prevent future accidents at its Lannate/API manufacturing building in La Porte, Texas, after four workers were killed by a lethal gas in November 2014.

"Four people lost their lives, and their families lost loved ones because DuPont did not have proper safety procedures in place," said Dr. David Michaels, assistant secretary of labor for occupational safety and health. "Had the company assessed the dangers involved or trained their employees on what to do if the ventilation system stopped working, they might have had a chance."

The fatal incident occurred as one worker was overwhelmed when methyl mercaptan gas was unexpectedly released when she opened a drain on a methyl mercaptan vent line. Two co-workers who came to her aid were also overcome. None of the three wore protective respirators. A fourth co-worker – the brother of one of the fallen men – attempted a rescue but was unsuccessful. All four people died in the building.

Methyl mercaptan is a colorless gas with a strong odor. It is used in pesticides, jet fuels and plastics. At dangerous levels of exposure, the gas depresses the central nervous system and affects the respiratory center, producing death by respiratory paralysis.

DuPont was cited for one repeat, nine serious and one other than serious OSHA violations. The repeat violation was assessed for not training employees on using the building's ventilation system and other safety procedures, such as how to respond if the fans stopped working. In July 2010, DuPont was cited for a similar violation. OSHA has fined the company $99,000.

DuPont has 15 business days from receipt of its citations and proposed penalties to comply, request an informal conference with OSHA's area director or contest the findings before the independent Occupational Safety and Health Review Commission.

For more information, visit www.osha.gov.