A cluster of new power plants proposed for the fringes of Northern Virginia's suburbs has alarmed local and federal officials who say the plants will make it harder to reduce smog in the Washington region and could trigger stricter controls for businesses and residents.

The plants are being proposed by Virginia Power, which serves more than 2 million homes and businesses, and by Old Dominion Electric Cooperative, a Virginia-based company that serves a quarter-million customers. In addition to positioning themselves for coming deregulation in the power industry, the companies say they need the plants to meet a growing demand for electricity in the region's suburban market. That demand has been especially acute during recent heat waves.

The natural gas-powered plants are proposed for an area of the state where they are subject to looser regulations than if they were built a few miles north toward Washington, within the boundaries of a regional smog-reduction zone. Within that zone, emissions of smog-producing nitrogen oxides from any new power plants would have to be offset by reductions elsewhere. Nitrogen oxides have been linked to respiratory problems in elderly people and children.

Only one of the plants, a 600-megawatt Virginia Power facility near Remington in southern Fauquier County, is actually under construction. The others under consideration include a Virginia Power facility near Ladysmith in Caroline County, and Old Dominion plants in Remington and near Boswells Tavern in Louisa County. The four plants are from 10 to 40 miles from the Washington smog-control area.

Environmental Protection Agency officials have recently warned Virginia regulators that the new plants could cause air quality to deteriorate in the commonwealth and in Southern Maryland, downwind of the plants.

A recent letter from a top EPA administrator to Virginia's secretary of natural resources, John P. Woodley, demands that Virginia keep federal officials informed of any additional power plant permit applications.

"I am concerned that a pattern of development is emerging, either through design or circumstance, that could circumvent the level of protection Congress intended" with the Clean Air Act, wrote mid-Atlantic administrator W. Michael McCabe in a letter to Woodley last week.

According to power company officials, plants are being located solely for convenience.

Virginia Power spokesman Jim Norville said regulatory concerns were not an issue in where the utility put its new plants.

"These sites are near, if not adjacent to, the intersection of natural gas pipelines and high voltage transmission lines. It has nothing to do with the location of the [smog-reduction] zones," Norville said. "These are ideal locations for these types of power plants--close to a fuel source and they can hook right into a transmission system."

Bill Sherrod, a spokesman from Old Dominion, said his company chose its site in Remington for the same reasons.

Virginia officials, who are embroiled in legal disputes with the EPA over federal air quality jurisdiction, have said it is too early to calculate the pollution effects from the plants, which would be powered by cleaner burning natural gas rather than coal. All but one of the facilities, they point out, are proposed, not under construction.

"It's too early from that standpoint," said James E. Sydnor, director of the Virginia Office of Air Quality Programs. "We haven't received complete applications."

But EPA officials fear that a growing number of such relatively small plants will be constructed outside the Washington area.

"At what point do you cumulatively assess the impact of all these facilities?" said Marcia Spink, an air quality official in the mid-Atlantic region.

Washington area officials charged with planning air pollution controls are worried about how much new pollution will blow into their back yards.

"Our ability to attain [pollution limits] is affected by the upwind states . . . such as Virginia," said Merrylin Zaw-Mon, a Maryland Department of the Environment official. "Virginia has to do its part."

With power plants in Remington, just 45 miles from downtown Washington, "it will make it more difficult for us to meet our health standards," said Loudoun County Supervisor James G. Burton (I-Mercer), who heads the air quality committee of the Metropolitan Washington Council of Governments. COG is responsible for making sure that the region meets air quality standards when they are imposed early in the next century and to develop additional restrictions if necessary.