A tractor-trailer carrying two highly flammable liquid paint removal solvents overturned and ruptured in Charles County yesterday, killing the driver. The truck sliced through a power pole, forcing a six-hour evacuation of about 100 persons because police feared sparks from the downed line might cause the cargo to explode.

"There was a great deal of concern about fire and explosion," said Sgt. Casey McDevitt, spokesman for the county sheriff's department. The accident closed Rte. 301 just south of LaPlata. The two-compartment tanker was loaded with 6,100 gallons of naphtha petroleum spirits and solvents and could have caused a "fierce explosion" if a fire had broken out, McDevitt said.

Killed in the accident, according to McDevitt, was Samuel I. Lowman, 64, of Brooklyn Park, Md., who owned the truck. An autopsy is planned, he added.

There were no other injuries, and state police said neither speed nor weather was a factor in the 8 a.m. accident.

Rush-hour traffic was diverted to back roads around the county seat of La Plata, while state highway administrators built a dike to contain the leaking fluids until it could be loaded onto another tanker.

Residents -- about 50 of whom spent the day at the local National Guard Armory -- returned to their homes about 3 p.m. after being assured by state health officials that the spill posed no immediate health hazard to well water in the area.

But McDevitt said water and ground samples are being taken from stream beds in areas near the spill to make certain that the solvents did not seep into the ground.

The tanker, under contract to American Tank and Transport Co. of Baltimore, was on the way to the Benjamin Moore Paint Co.'s division in Colonial Heights, Va., police said.