DuPont is under scrutiny from US federal records over a series of accidents involving toxic chemicals over the past seven years.

At least eight fatalities have resulted from the 34 accidents, according to research by the Texas newspaper Houston Chronicle.

The US chemical giant's accident record is in the spotlight after four workers died after exposure to the agrochemical ingredient methyl mercaptan at the group's La Porte plant, southeast of Houston, in November.

The latest accident is being reviewed both by the US Chemical Safety Board and the Occupational Health and Safety Administration (OSHA).

Houston Chronicle cited public records as a source of information about the three incidents involving toxic releases and non-fatal injuries it said had occurred at the Texas plant between 2007 and 2012.

The newspaper said the last time OSHA investigated an incident at the plant involving a worker was in 2007. It said OSHA records show DuPont paid a $1,800 fine for violating rules designed for companies that handle toxics. State environmental records also point to pollution problems at the same plant, it added.

According to the paper, it is not clear whether any agency investigated the other 2011 and 2012 accidents. Risk management reports show that DuPont handled the response internally.

Earlier this year, the Texas Commission of Environmental Quality issued an administrative order to curb excessive emissions of waste gas at La Porte that it said had been releasing excessive pollution since December 2011. Here, DuPont accepted a $92,000 fine and made upgrades to emissions control equipment.

David Uhlmann, a University of Michigan law professor, told Houston Chronicle that US state and federal environmental and workplace safety agencies do not always exchange information about incidents at plants that handle toxic substances.