Two workers were killed and two others injured in an accident Friday at Bell County Coal Corporation, an official said.

Suzy Bohnert, spokeswoman for the U.S. Mine Safety and Health Administration, said the accident occurred at a coal-washing plant when a parked dump truck suddenly rolled down a hill and demolished a pump house.

According to the Kentucky State Police, the two men killed in the accident were Oliver Beve Gregory, 51, of Pineville, and Donald J. Slusher, 56, of Hinkle.

Donald Engle Jr., 44, of Pineville, and Arlie L. Napier, 31, of Middlesboro, were both injured and transported to Middlesboro Appalachian Regional Medical center.

Federal mine inspectors were at the site Friday afternoon, Bohnert said. ''We're conducting an investigation into the circumstances surrounding the accident,'' she said.

Bell County Coroner Clyde Creech said the accident occurred about 12:30 p.m. EDT.

Four men were inside the building, Creech said. He said workers at the plant typically ate their lunch in the building because it was air-conditioned.

''One had parked the truck on a hill,'' Creech said. ''The truck started rolling down the hill and it hit the building.''

Creech said one of the injured has some bones broken.

The coal-washing plant is about three miles west of Middlesboro.

Middlesboro EMS and Bell County Rescue Squad each responded to the scene of the accident.

The Associated Press contributed to this report.

(Daily News staff report)