Three years ago, Marsha Hanson moved from Alexandria into a two-bedroom town house in southern Fairfax County, near Lorton Reformatory. She liked the county's schools and parks, and the prison didn't seem a bother to her.

Now, she isn't so sure. "As I said to my daughter last Friday night -- it was dark and she wanted to visit a friend -- but I said: 'No way. It's dark, and you don't know who's out there anymore.' "

Hanson, president of the Lorton Federation of Civic Associations, was voicing the heightened fears of many of the 13,500 residents who live in the Lorton area, a still-developing part of Fairfax, with hilly cow pastures, weather-beaten farmhouses and relatively few convenience food stores.

Yesterday, citing the last week's disruptions at the District-run prison, the Fairfax County Board of Supervisors voted unanimously to ask D.C. officials to discuss immediate plans for reducing crowding at the prison. "This is creating a very dangerous situation to the Lorton community," said Chairman John F. Herrity, a longtime critic of the prison.

The county board also voted to ask Northern Virginia's congressional delegation to help force the transfer of some prisoners to federal facilities around the country.

Board members also revived plans to bill the District for the costs of sending county police and fire units to the prison last week after two methane gas explosions seriously burned two inmates and forced the evacuation of a building that housed young prisoners. Fairfax police and fire forces returned Friday night after a disturbance erupted in a crowded youth facility -- an outbreak that ended only when police used tear gas.

Previous attempts to bill the District for such costs have failed.

While the county board was discussing the prison, residents of the subdivisions that have been built around the fringes of the sprawling prison complex were expressing their concerns about the facility's security and their fear of methane gas leaks from the landfill near the prison grounds.

Jackie Gibson, 32, the mother of two, said she and her husband dismissed fears of the prison when they moved to their Pohick Square town house 1 1/2 years ago.

"We knew about the prison when we moved here, and we thought about it," she said, while waiting for her children at a school bus stop. "But, our logic told us that, unless an escapee was going to take a hostage, he'd want to get as far away from here as possible."

Still, she said, she is troubled that she often doesn't find out about problems in the prison until she reads about them in the newspaper. Even the escape sirens, installed after the community protested about lax security, can't be heard well from where she lives, she said.

A friend of Gibson's, Mary Lou Richardson, 28, agreed. "They don't want to let us know what's going on," she said.

Missi Wayland, 18, lives within sight of the prison, and is positive about its impact on Lorton. Her mother and stepfather work there, and she said she is convinced it is safe. "Besides," she said, "if it wasn't for the prison, Lorton wouldn't even be on the map."

"Those prisoners can look out their windows and see . . . the garbage, and there's such an obvious odor that I was afraid they were going to have one heck of a riot this past summer," said Carol Wood, 45, owner of Carol's specialty store and a Lorton resident since 1969.

"I guess I was probably the only person in the world that didn't realize Lorton had a prison here when I moved in," said Robert C. Magor, who is director of occupational health and safety for the Environmental Protection Agency, and president of the Newington Civic Association. "The county has taken a lot from this area and has shown no inclination to reinvest," he said.

"I can't think of a whole lot of good things to say about the area," said William Seabolt, 59, a former D.C. corrections officer who has lived in Lorton since 1950. "It's got kind of a country atmosphere, but the county has chosen this end of things to use for a dumping ground."