Environmental protection officials from both Maryland and the federal government are setting up testing sites around the Rockville area this week to determine if dust from area roads contains potentially hazardous concentration of cancer-causing asbestoe fibers.

The actions come about six months after scientific studies first indicated that crushed serpentine rock from the Rockville-based quarry of the Rockville Curshed Stone Co. contained asbestos fibers so large they could be seen with an ordinary microscope. The quarry supplies the bedrock of most country roads, and the same serpentine Rock often is mixed with the asphalt that makes up most road surface.

The separate state and federal actions this week to establish monitoring stations around the Rockville area, however, have their origin in two separate events.

Ever since the revelation last fall that scientific studies had shown high levels of asbestos fibers in the sepentine rock from the quarry, officials of the federal Environmental Protection Agency had been meeting with state and county officials to determine how to deal with the situation.

The most recent of these meetings was held yesterday in Baltimore, when it was decided that the agency's senior environment engineer, Sims Roy Jr., would go to Rockville immediately to start looking for testing sites.

As that meeting was going on, officials from the Maryland State Department of Labor and Industry were discussing reports that an open area of road near a Gaithersburg elementary school might be sending up clouds of dust laden with asbestos fibers.

Yesterday afternoon, state toxicologist Oneill Banks informed Divisson Ayers, principal of the Watkins Mill Elementary School, that he intends to set up testing sites as soon as possible near the school.

A stretch of road about 30 feet long abutting the school's playground recently was covered with loose gravel from Rockville Crushed Stone when the old road surface disintegrated after the harsh winter.

On dry, windy days, clouds of dust from the road, kicked up by car wheels, have covered the playground. This situation was noticed by some pupils of Montgomery County physics teacher Donald Maxey, whose investigations originally had led to the discovery of asbestos fibers in the rock at the quarry last year.

Though what he calls "gross, visual test," Maxey last week found a quantity of large asbestos fibers in the dust near the school, which he described as "so thick you could hardly see through them."

When Maxey examined the dust through a standard optical microscope, he said yesterday, he found "gross fibers" of asbestos. He said "the really hazardous fibers, the ones the size of a virus, can only show up through an electron microscope."

He has given samples of what he found to Dr. Irving J. Sellikoff of New York's Mount Sinai School of Medicine, the nation's leading expert on the health hazards of asbestos, and he expects Selikoff to have test results from them in the next few weeks.

Oneill Banks of the state Labor and Industry Department said yesterday evening that "we don't feel there's too much cause for concern in the current Montgomery County operation" of Rockville Crushed Stone. He added that he thinks the planned tests at the Watkins Mill site will bear out this view.

Sims Roy, the EPA engineer, said that during his tour of possible monitoring sites yesterday, "I drove by (Watkins Mill) and it doesn't look very bad." He conceded, however, that on a rainy day like yesterday the dust would not be in evidence.

Richard Harris, head of the Washington-based Environmental Defense Fund, took a more pessimistic view of the situation. "There's a high probability that the concentration of asbestos (in clouds of this road dust) are many times greater than the amount of asbestos tailings in asbestos mining operations," he said.

This could present a grave health hazard, he said, if, as Dr. Selikoff's test have shown, even brief exposure to the fibers could cause some form of cancer two decades or more later.

There are U.S. regulations generating the amount of asbestos fibers that can be present in job areas, but none governing nonoccupational situations, he said.