Up to 1,000 times on the busiest days, trucks laden with asbestos-containing serpentinite rumble out of the quarry complex of Rockville Crushed Stone Inc., about three miles west of downtown Rockville.

Dripping water after driving through dust-control sprays on their way out of the quarry, the trucks pick up speed as they head east on Travilah Road, past houses, farm fields and small businesses, on their way to paving and construction jobs all over the Maryland suburbs.

Blue-gray dust coating the underbrush and weeds along the roadway attests to the passage of hundreds of thousands of such vehicles in the 32 years the 300-acre quarry has operated at Piney Meetinghouse and Travilah roads.

In recent months, a 10-year-old controversy has resurfaced over potential health hazards posed by the asbestos fibers in the ore. People who have come to live in relatively new subdivisions of $200,/000 and $300,/000 houses that are cropping up on former farmland in Travilah have raised fears that the asbestos, which can cause lung cancer, is being spread in the mining dust.

Last week, representatives of the state, Montgomery County, Rockville Crushed Stone and local civic groups met to hammer out the technical details of a $7,500 state study of air quality in Travilah. The state Air Management Administration agreed to compare asbestos fiber levels in the neighborhoods with those in an urban area, where asbestos from brake linings and other sources might be found.

Residents are hoping the state will go even further by trying to assess any potential actual health risks of living in the neighborhood.

"We can demand air as clean as the rest of Montgomery County and the state," said Michael Conti, who lives in the Hunting Woods subdivision near Travilah Road and who is chairman of the Citizens Technical Advisory Committee, representing area residents.

Elevated levels of asbestos, which was identified as causing cancer in concentrated levels in work places, were found a decade ago along Travilah Road and heavily traveled, unpaved roads. The state ordered Montgomery County to remove loose serpentinite from its roadways, and additional dust abatement methods were undertaken along Travilah Road.

But after that, "the issue died down, because the levels we had were not deemed to be a health risk," said Judith A. Whelan, who compiled a study of asbestos in the environment for the county in 1981.

Clouding the issue is a lack of federal standards over what constitutes an asbestos hazard in the outdoors, because it occurs naturally and is found in two-thirds of the country. Serpentinite, which occurs in narrow belts across the county and up and down the East Coast, typically contains 0.2 to 0.5 percent asbestos fibers, which are released in the air when the stone is crushed in mining and on highways.

Rockville Crushed Stone officials continue to maintain that their operation does not pose a health threat, and they say that is borne out by regular tests of quarry employes.

"The limited content of asbestos in this stone is so small that it would pass the {Environmental Protection Agency} standard for applying {insulation} to the interior of school rooms," said Robert Lanham, a planning consultant to the quarry company.

But residents are concerned and "want to put this issue to rest . . . to determine whether there is a health hazard," Conti said.

George P. Ferreri, director of the state's Air Management Administration, could not assure Conti that the results of the monitoring could be followed up with such assessments as studies of cancer rates in the neighborhood.

"There's no hope of more {state} money for monitoring, lab work and other resources," Ferreri told him at the meeting. "You're proposing a major, full-blown study . . . . "

James Topper, president of Rockville Crushed Stone, said his 135 employes do not take measures to prevent inhalation of the dust. "We get measured by federal inspectors all the time, and the exposures are all low," he said.

Topper, whose company uses street sweepers to curtail the dust along Travilah Road, has agreed to Ferreri's proposal that his company contribute another $7,500 toward air monitoring. Ferreri is first asking the state Ethics Commission whether that would be permitted under state rules.

State Del. Judith C. Toth (D-Montgomery), one of three state legislators who attended last week's meeting, said she was "not terribly optimistic about the long-term outcome" of the tentative agreements reached there after heated wrangling over testing methods and their scope.

She said an "undercurrent of distrust" about the issue meant that it may never be resolved.

"Whatever they find, one side will contest the findings," she said. ". . . The real villain is EPA. All over the country, people are crying for EPA to come up with standards" for testing asbestos in the environment. But in 10 years, "nothing has happened," she said. ". . . EPA says it is almost impossible, but it could do something."

When a publicity storm erupted over the use of serpentinite rock on roads and parking lots 10 years ago, Montgomery County spent $2.4 million removing it from school parking lots and playgrounds. Road shoulders were relined with limestone, and unpaved roads with serpentinite were resurfaced.

After monitoring air near the Travilah quarry, however, EPA and the county concluded that no health hazards were posed by the operation.

At the time, Maryland health officials proposed emergency regulations prohibiting the use of unbound serpentinite stone altogether. But Montgomery, home of the area's only serpentinite quarry, contended that too little scientific data was available to justify a ban. The state withdrew its proposal.

Rockville Crushed Stone has argued that it could cut back its operation at Travilah if the county would give it permission to open a diabase stone quarry near Boyds. Crushed stone from that quarry would be taken out by rail, rather than trucks.

But the County Council, bowing to local concern about traffic and pollution, refused to grant the zoning approval to open the quarry. The company is awaiting a decision in a court appeal.