People once made their living in the miles of hard coal mines that lace the ridgelines here. Now they fear the mines.

A team of federal and state environmental officials hastily assembled here says it believes that somewhere deep inside the long-abandoned mine shafts illegally dumped hazardous waste may have generated pockets of deadly hydrogen cyanide gas that can seep to the surface through hundreds of bore holes into the mines.

That posibility has touched off a wave of jitters among some of the 50,000 people who live in the five townships stretching over the surface of the mine, and has triggered one of the more unusual hazardous waste hunts experts here say they have ever undertaken.

Clad in yellow rubber suits with masks and gloves, and using special breathing apparatus, two crews of experts, dubbed Canary One and Canary Two, have begun gingerly probing the bore holes for signs of cyanide. The crews' names come not from the color of their equipment, but from the old mine practice of using canaries to sense deadly mine gas.

The crews also are carrying cyanide monitoring devices and capsules of amyl nitrite, and antidote to hydrogen cyanide poisoning. The crews roped themselves together, and an ambulance waited nearby.

Officials have ruled out entering the mine because of its crumbling condition and the estimated millions of gallons of toxic waste illegally dumped inside.

But they are trying to get a picture of where the gas pockets may be inside the twisting shafts.

Hydrogen, cyanide gas is lighter than air, and probably has collected in pockets against the ceiling of the mine shaft, the experts said.

Old-time miners have been called in to draw maps of the mines, but no one has been inside since the mines were abandoned in the late 1950s. There is little likelihood, officials say, that the old tunnel configurations remain.

"These things crumble and they shift all the time, and frankly, we have no idea if there is anything there or where it may come out of the ground if it is there," said Thomas Massey, the team coordinator for the federal Environmental Protection Agency. Massey is leading the search effort, headquartered on the banks of the Susquehanna River here.

A state grand jury investigation of hazardous waste dumping uncovered information that as much as 100,000 gallons of toxic materials containing cyanide may have been dumped into the mine, according to federal sources.

Officials here declined to comment on the grand jury investigation, but Massey said his crew has measured small amounts of cyanide in waste water flowing out of the mouth of the mine. State investigators found traces of cyanide in the outflow as much as two months ago.

Officials said several suspected carcinogens also have been detected in water flowing out of the mines. Floating containment bags are being used to hold back toxic waste flowing into the Susquehanna.

That information, and the possibility that hydrogen cyanide gas may be inside the tunnels, became known publicly only late last week, when news of the grand jury's findings leaked out.

The information caused some soul-searching among residents here. Authorities said they have received dozens of telephone calls from persons reluctantly admitting they had illegally tapped into the bore holes for sewage disposal.

"People are scared to admit they have been dumpling illegally, but they're more scared of the cyanide," said Anthony Attardo, head of the Pittston Township Board of Supervisors.

Attardo said dumping into the mines through the hundreds of bore holes here is a common practice, and that some housing developers even punched their own bore holes into the mines.

"There isn't anywhere else you can get rid of sewage here," Attardo said. He said Pittston Township, which covers much of the surface of the mine, has no sewers.

Attardo said residents also are frightened by the possibility that the hydrogen cyanide could explode if ignited, spreading a toxic cloud over the area. But environmental official officials said that, while such an explosion is possible, it likely would burn off the cyanide, reducing the hazard.