More than a year ago, Metro officials agreed to install emergency handles near the center doors of subway cars to allow passengers to escape quickly if an accident or a fire occurred.

Safety investigators had recommended the move after a January 1982 derailment in which three Metro riders died. Rescuers had taken 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.

Now, officials say, the emergency handles are being installed after a seven-month delay caused by a lag in obtaining the special equipment. The work started in October. It is expected that the devices will be installed by May in 100 subway cars, and signs are to be posted telling riders how to use them.

The entire 600-car Metro fleet is to be outfitted with the red handles by 1986, about a year later than planned. The cost has been estimated at $1.4 million.

In the past, Metro officials sought to prevent riders from leaving a rail car in an emergency without the aid of rescue workers. They feared that passengers might be endangered by the 750-volt third rail, and they expressed concern about possible abuse of the emergency devices by pranksters.

Officials now plan to take steps, including criminal prosecution, to prevent misuse of the handles.