The Metro subway's track maintenance workers charged yesterday that they were being endangered by a plan to use gasoline-powered equipment in enclosed tunnels. By the end of the day the plan had been shelved until the safety question is resolved by Metro officials and area fire chiefs.

Gary Young, a shop steward for Local 689 of the Amalgamated Transit Union, which represents most of Metro's employes, and 35 others signed a letter of Metro General Manager Richard S. Page charging their lives were being "placed in jeopardy" by Metro's intentions to use the track maintenance equipment.

Gasoline-powered equipment has been barred from Metro's tunnels since the subway opened in 1976, acting D.C. battalion fire chief McEldon Fleming said yesterday.

"If you use it in a tunnel, with poor ventilation, vapor will seep and pool [collect] at low points . . . Then, you have an explosive atmosphere," Fleming said.

In recent weeks, however, Metro has been seeking permission from area fire chiefs to use specialized railcutting equipment powered by gasoline engines. An exception to the ban on such equipment was granted last Friday by the D.C. Fire Department for work over the weekend, but Metro officials said the equipment was not used.

On Monday the fire department reinstated the ban after meeting with union officials, and referred the entire matter to the Metropolitan Washington Council of Governments' committee of area fire chiefs, which regularly resolves Metro safety issues.

Theodore Weigle, Metro's assistant general manager for transit services, said he first learned of the controvery yesterday.

"Under no circumstances will we put anything in those tunnels that jeopardizes employes' safety beyond the normal hazards of the workplace," he said. Gasoline-powered equipment, he added, will not be used without his permission or in violation of the law.

Weigle said that some rail-maintenance tasks "lend themselves to using the equipment because it is faster [than alternative tools] and has a substantial benefit to productivity, since we have such a short amount of time in the tunnels."