The Occupational Safety and Health Administration has classified DuPont as a severe violator of federal work place standards.
The decision follows the deaths of four employees during a massive gas leak last year in Texas.
The Wilmington News Journal reports that around 300 workers were making pesticide and other chemicals at the plant.
DuPont says that it is disappointed adding that the company has not yet had time to review decision.
The government says that preventable deaths and other serious problems were evidence of a failed safety program.
But company spokeswoman Kate Bailey said that the company disagreed with that assessment saying that firm had made progress in cutting the injury rates.