The Montgomery County Council established a 26-member task force yesterday to determine the presence and locations of toxic and hazardous substances in the county.

The task force was set up in response to community concerns about a report last month that Geomet Laboratory in Gaithersburg was testing toxic nerve gas under an Air Force contract in a facility adjacent to Washington Grove Elementary School.

County officials said Geomet complied with local, state and federal regulations concerning the handling of hazardous substances. The lab was testing four nerve agents and their ability to penetrate Air Force flight jackets.

The council's Health and Human Services Committee report said, "The laboratory was turned down by the Army for a contract involving hazardous substances on the grounds that the security of the facility was insufficient and the surrounding area too densely populated."

Present regulation of highly toxic materials in the county "did not address the kind of juxtaposition that had occurred in the Geomet-Washington Grove Elementary situation," the committee reported to the council. The task force will examine whether legislation is necessary "to allow more separation of toxic materials and vulnerable populations."

Currently, there is "no complete list anywhere of the toxic materials being handled or stored in the county," according to the committee report.

The committee considered two options to regulate firms dealing with toxic substances--requiring permits through the county fire code and revising zoning regulations. The committee report recommended amending the fire code "since the code already requires all toxic substances to have a permit, although the rules do not address the location . . . . At present the rules are very loosely enforced."

The task force will include representatives from the county's departments of environmental protection, health, public schools, fire services and the County Council. In addition the task force will have representatives from Geomet, the National Institutes of Health, citizens groups, Rep. Michael D. Barnes' (D-Md.) office, and advisers from the Maryland Department of Health and Mental Hygiene and the U.S. Environmental Protection Administration.

The task force is to document the kinds of toxic and hazardous substances "which are or might be handled" in the county, classify county land by population density and other factors that could increase vulnerability to such substances and recommend possible legislation. The task force is to submit a final report at the completion of a nine-month study.