Recent disclosures that a Gaithersburg laboratory has received 10 times more potentially lethal nerve gases than earlier disclosed have sparked new attempts by county, state and federal officials to restrict the use of toxic substances in Montgomery County.

A state Air Management Administration official is scheduled to conduct a special inspection of the Geomet Technologies facility on Atlas Drive today. The lab, which began testing nerve gases in 1983 in facilities constructed according to strict federal security standards, is regularly inspected by Army chemical surety officers, and company and military officials said the facility poses no danger to the community

Rep. Michael Barnes has sent a letter to the Army and Air Force, which have had contracts with Geomet involving the nerve agents, demanding to know why the testing is continuing in a residential area. He said he was disturbed because he had understood earlier comments by the Defense Department to mean that the testing had ended.

Barnes said yesterday that if the Department of Defense cannot respond with a satisfactory policy, he will consider introducing legislation to restrict the testing. He will also hold a town meeting Monday night at Gaithersburg Junior High School on the issue.

The Montgomery County task force, which was appointed in 1983 to establish a hazardous waste policy for the county after the reports of Geomet's first nerve gas shipments, has been called to an "emergency meeting" on Monday.

But these efforts are aimed at establishing future policy. In the adjoining neighborhoods of Washington Grove, Walnut Hill, Mill Creek Towne and Oakmont, where citizens groups have been meeting to organize publicity and lobbying campaigns, the question is more urgent.

"Geomet is 100 yards from the playground of Washington Grove Elementary School, and maybe 50 yards from the nearest house," according to Washington Grove activist Margaret Erickson, who has spearheaded resistance to Geomet since the first reports in 1983.

"One one-hundredth of a drop of some of this stuff will kill half the adults who inhale it, and it takes a whole lot less for kids," Erickson said. "I don't care how safe they say it is; the presence of lethal nerve gas in a residential area where kids play every day is absolutely unacceptable."

Under its Defense Department contracts, Geomet is testing the resistance of various materials and equipment to four chemical agents used as weapons: GD phosphine oxide (called GD) and VX ethyl S-dimethylaminoethyl methylphosphonothiolate (VX), both nerve agents, or chemicals that affect the body's nerve system and result in heart and lung failure; HD Bis (2-chloroethyl) sulfide (HD for short), the so-called mustard gas of World War I, and lewisite, a blistering agent.

Mustard gas and lewisite damage tissue on contact.

"We are not doing some Orwellian research to develop any new and horrible kind of chemical weapon," said an Army spokesman, Lt. Col. Craig MacNab. "We are trying to keep American soldiers alive if someone else uses chemical weapons on them."

But area residents are most disturbed by the large amounts that have been brought into Geomet, and by a recently released study dramatizing the potential risks of exposure to the agents.

In 1983, during the original controversy, Barnes and Republican Sen. Charles McC. Mathias said they were told by Air Force officials that Geomet had only 55 milliliters (1.86 ounces) of chemical agents at the Gaithersburg lab.

The letter, written by a deputy secretary of the Air Force's assistant for environment and safety, also said, "We have no further plans within this contractual effort for future shipments of chemical agents to Geomet," a phrase most area residents understood to mean that the nerve gas contracts would end.

However, last December, Geomet got a different contract to test the environmental controls of F16 planes that might be used to carry such agents.

Through an advisory sent in December to county fire and rescue workers warning them not to enter Geomet in case of fire, Erickson discovered that at least two more shipments of chemicals had been received at Geomet.

As of April 19, Army and Air Force spokesmen confirmed the presence of a total of more than 700 milliliters of chemical agents.

At the same time, the recent report of a citizens' task force in Cambridge, Mass., where an A.D. Little facility is testing the same four nerve agents, contained estimated lethal-dose and dispersal figures that have made the potential risk of an accidental release at Geomet far more frightening to area residents.

Using what is known as the LD50 test (the amount sufficient to kill half the exposed population), the Cambridge task force reported that 0.01 of a drop of VX, the most toxic of the four, would kill half the people directly exposed to it.

Mustard gas, the least toxic agent of the four being tested in Gaithersburg, takes half a drop to achieve the same results.

But such figures, and estimates of the spread of an explosive cloud or spill, ignores the strict packaging of such toxic materials, according to military spokesmen. According to MacNab, there has never been an accidental release of toxic gas in the decades of testing.

Geomet officials repeatedly have asserted that the laboratory poses no threat to community residents and that the extensive security precautions meet with all Defense Department and state requirements.

The controversy over Geomet, along with periodic protests against such other potential sources of toxic wastes as the Dickerson power plant, which may produce dioxin, and Neutron Products, which manufactures radioactive materials for medical therapy, has sharply highlighted a paradox that could have a serious impact on future Montgomery County development.

In a county that has nicknamed the I-270 corridor "Biotech Alley" as a mark of pride in its high-technology industries, and of its faith in a boom economy based on those industries, the growing grass-roots movement to restrict, if not outlaw, toxic substances comes as an unpleasant surprise.

"You're talking big money here," warned a county official. "Big money up front and even bigger money out the end."

"There's no argument that in the future, the county should be large enough that toxic substances won't have to be located next to the most vulnerable areas," according to Stewart McKenzie, the Montgomery County Council's legislative coordinator for environmental issues.

"But there are much broader economic implications to restricting use of toxic substances in a county where we actively court the presence of high-tech research and development and biomedical research companies."

McKenzie also suggests that trying to close existing facilities like Geomet might be costly, if such companies attempted to seek financial restitution.

But Erickson, who also serves on the task force on hazardous waste policy, said that quality of life cannot be laid beneath the economic bottom line.