The Environmental Protection Agency urged Montgomery County yesterday to immediately close or restrict access to hundreds of parks and playgrounds in order to protect citizens from airborne fibers of cancer-causing asbestos contained in crushed stone used on paths and play areas.

County park officials promptly ordered the posting of warning signs near play areas and other locations where the crushed stone is used as a ground cover, and they said that persons attending ball games in parks were being warned about possible health hazards. They declined to close the parks, however.

"We're not trying to panic the people in Montgomery County," said Stan Ernst, county parks director. "We're just trying to make them aware of the problem . . . It's a little precipitant to close down the parks."

The EPA also strongly recommended in a telegram to County Executive James P. Gleason that county building codes, which currently allow use of the crushed stone in the construction of public roads, private parking lots and driveways, be immediately altered to prohibit its use.

Additionally, Alvin R. Morris, EPA regional administrator and author of the telegram, said through a spokesman that he would "shortly" propose the nation's first set of standards to regulate the amount of airborne asbestos fibers permissible in nonindustrial locations. Currently the only standards in existence are those regulating asbestos in mining and industrial situations.

The EPA's actions and recommendations come after several months of study into the crushed stone containing asbestos that is mined in a Montgomery County quarry and used extensively on roads, driveways, and playgrounds throughout the Washington area.

Gleason declined yesterday to order any park closures or to restrict access. Instead, he sent EPA a telegram of his own asking if the federal agency would pay for any financial losses the county might suffer if it follows the EPA recommendations.

"It would be preferable if we were given an order (by EPA) because then we could break contracts, take action, and have a degree of (legal) protection," Gleason told reporters.

He said that country taxes would "almost certainly" increase if the county implemented the recommendations because the county would have to spend large amounts of money to resurface many roads, playground areas, and other areas where the stone is used. He said no immediate estimate of the cost was available, however.

An EPA spokesman said that a letter similar to that sent to Gleason has been sent to acting Maryland Gov. Blair Lee III asking the state to review its use - if any - of the asbestos-bearing rock on state roads.

"If necessary, we will issue the same recommendations to Maryland" agencies that were issued to Montgomery County, the spokesman said.

The EPA letter said, "Montgomery County should commence immediately remedial and permanent action to abate the potentially serious health problem resulting from the use of" crushed stone containing asbestos fibers. The EPA's telegram also called for a "permanent program to prevent a recurrence of the problem."

The specific recommendations included those for oiling or otherwise dampening roads that are paved with asbestos-laden stone, as well as stopping the use of that stone in future road construction.

Last Friday Gleason ordered a 30-day halt to road construction using crushed stone from the rock quarry, as well as an intensified oiling and dust dampening program, citing newly released EPA figures on the amount of asbestos present in the crushed stone used by the county as his reason.

Microscopic asbestos fibers are found locally in a rock known as serpentinite, which is the principal stone quarried by the Rockville Crushed Stone Quarry. Asbestos fibers can cause mesothelioma, a rare and always fatal form of cancer which does not show up in the lungs of its victims for at least 20 to 40 years after exposure to the fibers.

The Washington area has long been known to have high levels of airborne asbestos fibers. But the source of the asbestos was not discovered until last fall when two Montgomery County high school teachers, acting on a hunch that the asbestos might be coming from rock mined at the Rockville quarry, decided to conduct their own tests of air near the quarry site.

The two teachers, Don Maxey and Raymond Kent, sent their samples to the nation's leading authority on asbestos, Dr. Irving J. Selikoff, at New York's Mount Sinai Medical Hospital.

Selikoff subjected the air samples to highly technical analyses and found that "significant and dangerous amounts of asbestos fiber are coming out of the (Rockville) quarry."

In late September, representatives of a dozen local, state, and federal agencies concerned with air and water quality and public health hazards, met in Rockville to discuss the situation. Various tests have been taken by various agencies since then, with the EPA's preliminary results announced last Friday.

Last May 10, the nonprofit Environmental Defense Fund threatened to sue the EPA unless it took "emergency action" to stop Montgomery County from using serpentinite in its road paving program.

James Topper, general manager of the quarry that sells the serpentinite used for road construction, schoolyard paving, and virtually all other kinds of paving situations throughout the metropolitan Washington area, did not return telephone calls to his office yesterday.