A tanker truck carrying liquid latex burst into flames last night on Interstate 66 just outside the Capital Beltway in an incident that caused several injuries, damaged cars and backed up traffic near one of the region's key intersections.

The accident occurred about 9:45 near Cedar Lane, east of Nutley Street and west of the Capital Beltway, according to witnesses. Officials said none of the latex spilled.

Virginia State Police said six people were injured and taken to hospitals. Their conditions did not appear to be life-threatening, authorities said.

The cab of the tanker was destroyed by fire, and a minivan in the eastbound lanes of I-66 was gutted, said Dan Schmidt, a county fire and rescue spokesman. Three other vehicles were damaged, but none apparently caught fire, Schmidt said.

Preliminary investigation indicated that the minivan and the tanker truck collided, according to state police Sgt. Terry Licklider. Damage to the other three vehicles might have resulted from a chain-reaction collision, he said. Witnesses were being interviewed early this morning.

A woman who lives in the area said she was aware of the accident at the moment it occurred, asserting that it sounded like a detonation.

"I heard it when it exploded," said E.L. Carr, who lives in the Vienna area. "I knew something exploded."

Carr called the noise she heard "a loud explosion, like a tire blowing out."

"Like a big boom-bang," Carr said.

That sound, Carr said, was swiftly followed by the wail of the sirens.

Another resident of the area said he had "been hearing sirens for the last hour going down 66."

The fire appeared to be largely extinguished by about 10:30 p.m.

The truck, with its shiny cylindrical tank, appeared to have come to a halt upright and at an angle to the direction of traffic.

The accident suspended Metrorail service between the Vienna and Dunn Loring stations on the Orange Line for about an hour. At the point where the accident occurred, the Metrorail tracks run between the eastbound and westbound lanes of the highway.

Metro spokeswoman Lisa Farbstein said buses were provided to carry passengers between the two stations at the western end of the Orange Line. She said normal service was restored about 11 p.m.