Four workers at DuPont’s La Porte, Texas chemical plant were killed after exposure to a deadly chemical leak, the cause of which is still unknown, reported Reuters. This incident is the latest in a long timeline of tragedies surrounding the chemical company, DuPont.

The leak occurred early Saturday morning around 4 a.m., releasing the deadly chemical methyl mercaptan. Five plant workers were severely affected after exposure to the deadly chemical as four died, including two brothers, and one other who was rushed to a nearby hospital.

DuPont spokesman Aaron Woods won’t say how the plant found out about the leak. Methyl mercaptan, like propane, remains in a liquid state when contained but converts to a gaseous state when mixed with oxygen.

Since at least the year 2000, the DuPont chemical company has gotten into many scrapes with the law for similar incidents. From chemical leaks to hiding important documents, DuPont has been ordered to pay hefty fines for its crimes. It is used as a pesticide and fungicide.

In 2000:

  • DuPont paid a $1.5 million settlement related to a sulfuric acid release of which the company did not notify the proper officials

In 2003:

  • DuPont was ordered to pay millions to 30 British families and an American family who sued the company for causing their children to be born without eyes. The chemical linked to the birth defects was Benlate, a pesticide.
  • DuPont was found to have conducted human experiments where “volunteers” smoked Teflon-laced cigarettes in the 1960s. Despite Teflon’s deadly effects, the company asserted the chemical was safe.
  • The company was sanctioned for destroying evidence and failed to produce important documents.

In 2004:

  • The EPA filed a claim against DuPont asserting that the company withheld information about people exposed to perfluorooctanoic acid (PFOA). PFOA passes on from pregnant women to their babies causing various birth defects.

In 2005:

  • DuPont was order to pay over $10 million in fines and $6.25 million for environmental projects over allegations made by the EPA that the company withheld information about PFOA’s health effects for 20 years.
  • The company settled a 2001 class action suit for $107 million with 80,000 Ohio residents over C8 poisoning. C8 in the key chemical in Teflon.

In 2011:

  • DuPont was fined $500,000 for illegal pollutant discharge and non-compliance.

In 2013:

  • The company paid $800,000 in fines concerning clean air violations and failure to monitor its releases.

In 2014:

  • DuPont was fined $1.275 million for leaking deadly chemicals into the air which killed one DuPont employee.
  • An EPA consent order imposed a $1.85 million civil penalty because the company withheld 18 adverse event reports concerning tree poisoning from the herbicide Imprelis.

These are just a few of the recent instances of DuPont’s misconduct. Lives were lost or damaged, and plant life has suffered because of DuPont chemicals. Considering the company’s tendency to hide information, will the company be so forthcoming about the incident that killed four Texas workers on Saturday?

Federal investigators have been dispatched to the La Porte plant to find answers regarding the deadly chemical leak.