SEATTLE (AP) - A homeless man in a sleeping bag was accidentally run over and killed by a brush-cutter clearing blackberry bushes at a highway project in south Seattle, authorities said.

It happened when a subcontractor was preparing a site under Interstate 5 for a bridge expansion joint replacement, the state Department of Transportation said.

The victim, identified as Isaac Palmer, 62, died of skull fractures and brain lacerations caused by sharp and blunt-force head trauma, the King County medical examiner's Office said.

"This appears to have been a terribly tragic accident," Transportation Secretary Doug MacDonald said in a statement.

Russ East of the Transportation Department said the equipment had been operating for about a half hour when the man was hit. Palmer was run over around 11:30 a.m. Saturday.

Last week, police had asked transients to leave the area, which is posted with no trespassing signs, warning them that the brush-clearing work would be taking place. A special subcontracting crew also worked to remove human waste, needles and other drug paraphernalia from a mile long section under the freeway.

DOT was checking to see whether all steps were taken to confirm the area was safe for the work before the brush-clearing began, and MacDonald said his staff would re-examine its procedures to prevent such an accident from happening again.

The state Department of Labor and Industries was investigating the death.