A 27-year-old inmate serving time for burglary, murder and armed robbery escaped from Lorton early ysterday under the cover of a heavy fog.

Melvin Stewart, who was serving a 15-years-to-life prison term in the central facility, scaled the fence between two guard towers at 2 a.m., before a guard detected him and fired two shots at the fleeing inmate, D.C. correction officials said. No one knows if any of the shots hit Stewart.

J. W. B. Richards, chief union representative for the correction officers, blamed the escape on the shortage of correction officers. "It definitely could have been avoided if we had enough people down there," he said.

During foggy weather, a special fog detail is assigned to patrol the fences around the facility to prevent escapes, officials said. However, because of the staff shortages, some posts were undermanned, officials said.

"They are going to have to do something about the staffing or else they will have a summer of escapes," said Richardson.

He said a disturbance two weeks ago in which five inmates were injured and mattresses in a dormitory were set on fire could have been pervented if there had been more correction officicers on duty.

The last escape from Lorton was in December during foggy weather, officials said.