Every day 3.5 million people ride on 6,200 subway cars throughout New York City. Every year there are some 5,000 reports of fire in the subway system. Most are not major, but there have been six evacuations of passengers from subway tunnels during 1984, and nine fires where passengers required emergency treatment.
Although millions ride the system safely each day, the fire problem became serious enough this year that the National Transportation Safety Board (NTSB), a federal agency, recently sent up a team of inspectors to investigate.
Jim Burnett, head of the NTSB, said the investigators came here, because the risk of fires had reached an unacceptable level.
''As to the level of risk, I haven't changed my opinion at all,'' he said at a Monday press conference on the findings of the week-long investigation. But he also said that a final report would not be made for several months until an ''extended process of analysis'' was complete.
''It is entirely possible that new questions will arise,'' said Mr. Burnett. ''I am not ruling out a follow-up investigation.'' He also pointed out that beyond documenting the severity of the problem in New York City, the NTSB would offer suggestions to improve safety on the subway.
Equipment and trash fires are often produced by electric arcing of the so-called third rail that powers the subway with more than 600 volts. The two are the most common fires in the system. Debris collects from loose trash swept into subway tunnels along with bags of collected trash that hasn't been picked up.
One of the greatest hazards was at the 95th Street station in Brooklyn, where a locker with open cans of paint and kerosene was located near the third rail. Bags of debris were also nearby. The walls showed evidence of an earlier fire in the same location.
In the past, the NTSB has recommended that the New York City Transit Authority put fire extinguishers on each subway car. The TA has declined, saying that extinguishers are available every 300 to 400 feet in the tunnels, Burnett said. But his investigators found that the extinguishers were sometimes missing or empty. In several places, a train operator would have to walk ''a mile or more'' to find a working fire extinguisher.
Burnett did report that the electrical feeder cables to the third rail were mostly in good shape and were not a major factor in fires.
''The good news is that the system does not need to be rewired,'' he said.
''We are not trying to panic people, to stop them from using the subways, or (make them) excessively fearful,'' but only to help correct problems and make the system as safe as it should be.