The state has launched an investigation into a fatal industrial accident at the Kekaha Landfill on Kauai.

A 56-year-old employee who died in the accident has been identified as Gary Soto of Kalaheo.

At about 8:55 a.m. Sunday, Soto was operating a road grader at the facility at 6900 Kaumualii Highway when the accident occurred, prompting an emergency closure of the landfill. The heavy machinery is used to grade and terrace the area to keep refuse from sliding. The landfill area is roughly 40 acres.

The Kekaha facility remained closed for the remainder of the day and reopened Monday morning.

Kauai County spokeswoman Mary Daubert declined to provide details on the accident because of the ongoing investigation.

An investigation by the Hawaii Occupational Safety and Health Division of the Department of Labor and Industrial Relations is underway. A compliance officer was to travel to Kauai from Oahu on Tuesday to investigate for the next few days.

Bill Kuntsman, spokesman for the department, said the state does not know what caused the accident.

An internal investigation and a separate investigation by the Kauai Police Department have also been initiated.

Daubert said she is not aware of any other fatal industrial accidents at the landfill.

Soto had worked as a landfill operator at the facility since July 2006. He was among nine county employees working at the site Sunday.

One employee from Waste Management of Hawaii Inc. also was at the facility at the time. The waste services company operates three landfills in the state: the Kekaha landfill, the Waimanalo Gulch landfill on Oahu and the West Hawaii landfill on Hawaii island.

A company representative could not be reached for comment.