About one-third of the students at the Watkins Mill Elementary School in Gaithersburg stayed home yesterday after widely publicized but unvertified reports that clouds of dust blown over the shcool playground from a nearby gravel road may contain cancer causing asbestos fibers.

"There seems to be some feeling among parents to keep their kids out until this dust is under control," school principal Davisson Ayers said yesterday.

Ayers has been informed by officials from the city of Gaithersburg that the gravel stretch of road, about 30 feet long, will be paved over this morning.

In addition, Ayers expect a report by this afternoon from the Maryland Department of Labor and Industry in Baltimore, which set up four separate testing sites at the school yesterday to sample the air.

About 200 students were absent from the school yesterday, compared to a normal figure of 30 absentees. "This indicates the level of concern parents felt because of news reports," Ayers said.

"It's been a very busy day," he sighed."The phone rang off the hook from the moment I walked in. Parents who hadn't heard about it on TV or hadn't read the papers heard from other parents and asked to take their kids home."

In addition, state inspectors set up their instruments at four sites in and around the school under the direction of state toxicologist Oneill Banks. The samples will be studied on a "rush" basis," Ayers said.

News reports on the possible problem at the school were aired earlier this week after visual tests by a local physics teacher indicated the presence of asbestos fibers in the dust blown from the gravel road.

The teacher, Donald Maxey, had worked last year with a nationally-known cancer expert. The pair determined th at the rock used to pave most Montgomery County roads contain asbestis fibers.