Metro officials have begun installing emergency handles near the center doors of subway cars to allow passengers to escape quickly if an accident or a fire occurs.

The move stemmed from recommendations by safety investigators after a January 1982 derailment in which three Metro riders died. Metro officials said the new handles should be pulled only if there is a fire, dense smoke or other life-threatening emergency.

The devices have been installed in more than 40 of Metro's 454 subway cars. A total of 110 cars are to be equipped with the handles by August, officials said, and Metro's other cars will be outfitted with the devices within a year.

The $1.4 million plan, approved by the Metro board in December 1982, was delayed about a year because of difficulties in obtaining the special equipment.

The handles have long been a focus of controversy. Before the 1982 derailment, Metro officials contended that passengers should not be allowed to leave a train without assistance from rescue workers. They cited dangers from the 750-volt third rail and concern about possible abuse by pranksters.

The authority's evacuation policies triggered objections, however, from the National Transportation Safety Board and local fire officials. They argued that it might take too long for rescuers to reach a train after a severe accident.

After the 1982 derailment, rescue workers took more than an hour to evacuate passengers from the damaged train, raising concern that more lives might have been lost if a fire had broken out.

Officials said they have taken steps to prevent misuse of the handles. The devices are designed to open the doors only after a train has stopped, officials said. In addition, they said, passengers convicted of misusing the handles face possible fines and imprisonment.

In a pamphlet being distributed at rail stations, the authority says the handles should be pulled only "as a last resort." It urged passengers to wait for instructions from a train operator or contact the operator on the train's intercom system before using the emergency devices.

"If a passenger opens an emergency door prematurely, the train cannot be moved. A hasty action like this could create a more dangerous situation," the pamphlet says.