Imperial Sugar has been fined almost US$9m for safety violations after an explosion at its sugar refinery in Wentworth, Georgia, killed 13 workers and injured dozens more.

Announcing the US$8.77m fine, the US Occupational Safety and Health Administration said that it found combustible sugar dust had accumulated in the plant and on equipment, citing 108 safety violations.

Moreover, the OSHA said that one month after the February explosion the company "had done little" to abate similar conditions at another of its plants in Gramercy, Louisiana.

Edwin Foulke Jr., administrator of OSHA, said he was "outraged that this company would show a complete disregard for its employees' safety by knowingly placing them in an extremely dangerous work environment".

Imperial Sugar said that it intends to contest the fines.

"We have filed with OSHA a 'notice of contest' of the citations, in which we challenge the allegations of the citations, the characterisation of the violations and the penalties proposed. In short, we believe that the facts do not merit the allegations made," the company's president and CEO John Sheptor said.