State police officers in Maryland and Virginia said that the Labor Day weekend's less-than-perfect weather apparently kept people off the highways and made driving easier and safer this year.

In both states, traffic deaths for the holiday period were far lower than in 1986.

By late afternoon Monday, only two persons had died on Maryland highways, compared with 11 last year. And in Virginia, nine persons had been killed, down from last Labor Day's count of 23.

Officials in both states said this year's count could rise because any accident before midnight would be added to the Labor Day total. They also said some local accidents might not yet have been reported to the state police.

By late Monday, the Washington area had had no fatal accidents. Fire at Georgetown LaboratoryA fire broke out yesterday at Georgetown University's science center, damaging a chemistry laboratory and releasing hazardous smoke into other sections of the building, D.C. fire officials said.

Four graduate chemistry students were treated at the college's hospital and released, officials said.

The students, whose names were not made public, had been working near a sixth-floor laboratory in the Rice Building when the fire was reported about 3:05 p.m., Deputy Fire Chief Bernard Johnson said.

Hazardous fumes were released when plastic containers filled with unidentified chemicals burned, officials said. The cause of the fire was under investigation.

Fire officials said they planned to contract with a private company to dispose of the chemicals. Emergency Landing at BWI A Piedmont Airlines jet with 36 passengers aboard made an emergency landing at Baltimore-Washington International Airport yesterday after a warning light falsely indicated that one of its engines was on fire.

Paul Foley, the airport's operations manager, said the plane took off from BWI but returned about 9:45 a.m. when the emergency signal went off. The passengers and crew were evacuated by emergency chutes, officials said. No one was reported injured in the incident.

One of the plane's two engines was shut off when the trouble light went on, Foley said, but he added that the craft, a Boeing 737, had no trouble flying on the remaining engine.

Baltimore Officer Shoots Roommate A Baltimore County policeman accidentally shot and seriously wounded his roommate while the roommate was taking a shower in their home, police said.

Police have questioned the officer and were treating the Saturday night shooting as an accident, Cpl. Paul Dunn said Sunday.

John Copenger, 28, of Chase, was flown to University of Maryland Shock Trauma Center with a gunshot wound to the chest, Dunn said. Copenger was listed in serious condition Sunday.

The officer, Thomas Manzari, was standing in the bathroom of their house when he removed the gun from his holster.

The gun went off, striking Copenger in the chest while Copenger was in the shower, police said.

Manzari, a three-year member of the county police force stationed in North Point, reported the shooting, police said.

More Flooding Reported in Va. Heavy Labor Day rains brought minor flooding in southwest Virginia while the Tidewater area tried to dry out from a Sunday dousing.

The National Weather Service issued a flood watch for much of southwest and western Virginia yesterday after heavy thunderstorms dumped between 3 and 4 inches in some areas.

On Sunday, a front stalled over the Norfolk-Portsmouth area, pouring nearly 5 inches on downtown Norfolk and causing heavy street flooding. Police said it was impossible to estimate how much damage was done.

Flooding in Portsmouth was not as severe.

More than 2 1/2 inches fell in the Roanoke Valley, causing some flooding of secondary roads in Henry and Franklin counties. A portion of the Blue Ridge Parkway was closed when a creek washed over the roadway.

The rain did not come in time to help the state's parched corn crop.

"This has been the history of our weather this year," said Louis J. Schiemann Jr., extension agent in Franklin County. "It all comes during a certain period, and then we have the long dry spells."

Schiemann said the moisture would help the pastures. Cattle ranchers have been putting out winter feed for their livestock because the pastures have been so dry.

A weather service spokesman in Norfolk said the heavy rains Sunday were not unusual -- it was where they fell that made the difference.

"What happened was merely a thunderstorm stalled over the city of Norfolk and parts of the city of Portsmouth. It caused local flooding of the streets," said Robert Bottom.