Maryland State Police were investigating a fatal accident involving a tractor-trailer Tuesday morning on the north side of Interstate 695's Inner Loop, near the Providence Road area.

About 4:30 a.m., a tractor-trailer "hit an unattended vehicle that was sitting on the shoulder, and also the concrete abutment, and turned over," said Sgt. Douglas Forrester of the state police. The driver of the tractor-trailer was killed, Forrester said.

Police were working to identify the man, who Baltimore County emergency crews pulled from the vehicle after they extinguished a fire that erupted after the tractor-trailer hit the highway barrier, said Elise Armacost, a spokeswoman for the department. The driver was pronounced dead at the scene.

The truck was loaded with calcium carbonate, often used in road-building or in preparing cement. Armacost said the material is not hazardous. Two units from the Maryland Department of the Environment also responded to the accident.

Three Inner Loop lanes that had been closed were reopened to traffic by 8:30 a.m., but an off-ramp lane remained closed at the scene, according to the State Highway Administration.

jtorbati@baltsun.com