Irene McCabe's daily routine and happiness depend on which way the wind blows.

If it's blowing west or south, the Silver Spring resident can hang her clothes outside to dry, water her flowers and barbecue. If it's blowing north, or east, McCabe said, she locks the doors and windows and becomes a prisoner in her own home -- because the air outside smells "like a dead animal."

McCabe, 63, lives with her husband about a half mile from the Washington Suburban Sanitary Commission's 116-acre sewage composting facility, which is on the border of Montgomery and Prince George's counties. Using wood chips as the oxidizer, the plant composts sewage that has been treated at the Blue Plains plant in the District, with the resulting product sold as fertilizer.

The 2 1/2-year-old facility has come under fire from neighborhood groups and local legislators because the odor hasn't gone away, even after the WSSC spent about $4 million to correct the problem.

"If the wind isn't blowing in my direction, people who live on the other side of the plant have to put up with the smell," McCabe said. "And if it's a hot and humid day with little air movement, then we all suffer."

Last Sunday about 350 residents of that area, most of them members of a group called Neighborhoods Organized to Support Eradication of Stench (NOSES), went to the plant on Industrial Parkway near Rte. 29 to demonstrate their concern. They wore clothespins on their noses, waved signs and released 500 helium balloons reading "Site 2 -- P.U." (The plant was the second alternative of 20 sites considered when it was selected in 1978.)

The protesters want the plant shut down, and they say they have the support of at least eight local and state legislators, some of whom spoke at the demonstration.

Loretta Storm, who formed NOSES five months ago, said the foul air reaches an estimated 30,000 persons living within three miles of the plant. Some have complained of allergies, watery eyes, scratchy throats and sinus problems that they contend are caused by the discharges. However, county and state department of health officials maintain that the plant is not a threat.

"Based on the work we've done at the site, we don't have any reason to believe there is a health risk," said William Eichbaum, state Department of Health and Mental Hygiene assistant secretary for environmental programs. The plant, the only composting plant run by the WSSC, is working at 50 percent of capacity and should be processing 400 tons of sewage a day within a few months, said Marjorie Johnson, WSSC director of public affairs. Johnson said about $4 million has been spent trying to eliminate the smell.

Steps have been taken to remove odor-causing chemicals from the air, blowers have been installed, the exhaust system has been modified and further studies are under way, she said. A progress report on the studies will be discussed tonight at 7:30 at the plant.

But Del. Diane Kirchenbauer (D-Montgomery), who represents the Silver Spring area, said the changes haven't worked, and she said she would rather have the composting done elsewhere. She sent a letter, signed by seven other state legislators, to Adele Wilzack, secretary of the state Department of Health and Mental Hygiene, requesting a meeting to discuss alternative sites for the plant.

The state health department issues the permit that allows the plant to operate. The permit states that the plant is to be closed if an "environmentally degrading or nuisance condition" develops during the operation, according to State Sen. Arthur Dorman (D-Prince George's).

Dorman said the permit should be revoked because "If you go out there and the wind blows the right way, it's more than a nuisance."

Michael Gudis, president of the Montgomery County Council, said a task force formed several months ago has been studying other ways to make use of the sewage without moving the plant. The options include selling the material to farmers for land application, injecting it below the surface to fertilize fields of seed crops for animal consumption or enclosing the composting plant.

Real estate agent Richard Cramer, who lives in the area, said the odor has prompted some homeowners to sell out, accepting below-market prices because the odor is discouraging prospective buyers from looking there. Cramer said neighborhood residents who are going public with their concerns about the plant may be serving to help lower their own property values.

"The publicity is like a kiss of death," he said. "If the plant stays there and this effort doesn't work, the whole world is going to know about the bad smell in Silver Spring, and property values will really go down."