Steam Pipe Explosion Jolts Midtown

A steam pipe explosion beneath a street near Grand Central Terminal yesterday propelled a giant scalding jet of brownish steam toward the sky, sending commuters who had been heading home stampeding to safety.

Officials said that one person died and more than 30 were hurt, two of them critically. The city said that three firefighters and one police officer were among the injured.

The blast, near 41st Street and Lexington Avenue, raised fears of terrorism, but officials were quick to dismiss that possibility. “There is no reason to believe this is anything other than a failure of our infrastructure,” Mayor Michael R. Bloomberg said.

The explosion sent up a foul cloud of hot steam mixed with mud, rust-colored gunk and pieces of pavement just before 6 p.m. in one of the busiest parts of the city. The mayor said that some telephone lines had been knocked out, but that electric power had not been.

As people on the sidewalks scrambled to flee and office workers in the buildings above looked down in horror, debris from the geyser pelted nearby skyscrapers. Then it rained on the streets like a sudden hailstorm. Some witnesses said the jet of steam roared like Niagara Falls.

Some people ran so fast their shoes came off. Others dropped their briefcases and purses. Men in tailored suits were caught in a lapel-singeing cloud. At a health club high up in the Grand Hyatt hotel next to Grand Central Terminal, people working out on the treadmills said the explosion was so powerful they worried the building would collapse. The steam shot up from a crater that looked like that of a volcano, with orange flames and bubbling mud around the edges. The explosion packed enough force to flip over a tow truck that ended up in the crater, which was about 35 by 40 feet. Several hours after the blast, officials said the crater could grow even larger because pavement at the edges was in danger of collapse.

The cloud of steam — and the hail of debris that followed — lasted more than two hours and raised concerns about asbestos, which was used when the pipe was laid in the 1920s. Officials advised people who had been in the neighborhood to discard their clothes and bathe carefully.

The mayor said the explosion appeared to have been caused by cold water that reached the pipe, which measured more than a foot and half in diameter and dated to 1924. “Cold water apparently causes these to explode,” he said.

Con Edison, which maintains the steam pipes beneath the city’s streets, said the pipe ruptured at 5:56 p.m. Kevin Burke, the chairman of Con Edison, said crews had checked the pipe after the thunderstorm that soaked the city in the morning. He said a heavy rain can cause a “vapor condition” if rainwater seeps onto a steam pipe, causing the steam to condense. He said the inspection earlier in the day had given no indication that anything was amiss.

Michael S. Clendenin, a spokesman for the utility, said tests would be conducted for asbestos. “We always assume there’s asbestos in a steam pipe,” he said, “so we are treating these materials sent up by the rupture, including piping, as if asbestos were in them.”

There have been more than a dozen steam pipe explosions in the city in the last 20 years. One of the largest shook the neighborhood around Gramercy Park in 1989 and did millions of dollars in damage. Three people were killed, two of them Con Edison employees who had been working in the street before the explosion.

Within hours of the blast yesterday, Con Ed and the city’s Department of Environmental Protection began taking air samples to determine whether asbestos had been released. They were also checking the debris that littered the street. Mr. Bloomberg said subway entrances and exits would also be tested.

The mayor urged people who might have come into contact with mud or soot from the blast to wash carefully, and to have their clothes cleaned separately as soon as possible.

Jessica Leighton, a deputy commissioner at the Department of Health and Mental Hygiene, also cautioned people inside buildings near the blast to close windows and set air-conditioners to recirculate the air inside instead of drawing in air from outside.

Asbestos is a known carcinogen. Most health officials say there is no safe level of exposure. But asbestos-related diseases generally are linked to sustained exposure in industrial settings over many years.