NEW YORK ( CNN ) -- The air was declared clean , but the carcinogen asbestos was found in dust and debris hurled into midtown Manhattan by a steam pipe explosion the day before , New York City announced Thursday . A steam pipe burst in midtown Manhattan during rush hour Wednesday . The city 's Department of Emergency Management will continue to test the debris after finding asbestos in six of 10 samples , according to a statement from the city 's Office of Emergency Management . `` People who may ( have come ) into contact with the steam or debris should take a shower and place their clothes in plastic bags for cleaning or disposal , '' the statement said . Asbestos is a fibrous mineral used to insulate pipes . Longterm exposure can cause allergies , skin problems and cancer . The 6 p.m. blast , which sent sent plumes of smoke and ash into the air around Grand Central Terminal , killed a woman and injured at least 44 , according to authorities and local hospitals . Watch an I-Reporter 's video of `` volcano '' in street » . Lois Baumerich , of Hawthorne , New Jersey , died of cardiac arrest , New York City Mayor Michael Bloomberg said . Three firefighters and a police officer were treated on the scene for minor injuries , according to a New York Fire Department spokesman . Bellevue Hospital Center received 14 patients , including Baumerich , hospital Administrator Larry Dugan said . New York Presbyterian Hospital said it received 27 injured people , 25 of whom were treated and released . As of Thursday , one person was listed in critical condition and another in serious . The area encompassed by 40th and 43rd streets and Vanderbilt and Third avenues was `` frozen '' because of the asbestos threat . Map of blast site » . Those in that zone are allowed to stay in the area , but should use caution . No one will be allowed to enter the zone , the Office of Emergency Management said . `` People inside buildings in the frozen zone should keep windows closed and switch air conditioners to recirculate the air inside instead of drawing in air from outside , '' the office said . Also , parts of Lexington Avenue , Third Avenue , Park Avenue , 42nd Street and Vanderbilt Avenue will be closed to traffic . Subway lines near the explosion were initially rerouted to bypass Grand Central Terminal , but the Metropolitan Transportation Authority said Thursday the subway infrastructure was not damaged . Bloomberg told reporters the pipe that exploded was installed in 1924 . `` There was cold water getting into the pipe , and cold water apparently causes these to explode , '' the mayor said . `` It might have been bursts of cold water from the rain or because of another water main break . '' Hundreds of people frantically fled the scene as police , fire and utility officials converged on the area around the blast , which left a crater 25 feet wide and 15 feet deep , according to utility provider Con Edison . More than 170 firefighters were dispatched to the site , the fire department said . Blast leaves massive crater » . `` The ground was literally shaking under your feet , '' New York police Deputy Commission Paul Browne said . Video from the scene showed steam and mud erupting from underground . A small school bus had its windows and one of its doors blown out . One witness , former CNN reporter Adaora Udoji , described the scene as `` pandemonium . '' Within about 20 minutes , she said , authorities had the entire area locked down . `` It felt like an earthquake . We saw hundreds and hundreds of people running down Third Avenue , '' she said . `` They were screaming , they were crying . '' The New York Times reported that the rush-hour blast sent up a geyser of steam , mud and rust-colored gunk , and displaced chunks of pavement in one of the busiest parts of the city . Pedestrians scrambled to flee the blast -- some running out of their shoes -- as those working in the skyscrapers pelted with debris looked down in horror , the newspaper reported , comparing the aftermath of the blast to a hailstorm . Some witnesses said the jet of steam roared like Niagara Falls , The New York Times reported . Carol Bergendale , who witnessed the blast , told WABC that commuters in the area began driving in the wrong direction to get away . Despite initial fears , Browne said the blast had nothing to do with terrorism , and the FBI said there was nothing suspicious about the blast . In August of 1989 , three people died related to a steam pipe explosion in Gramercy Park . E-mail to a friend . CNN 's Amy Sahba and Katy Byron contributed to this report .
NEW : 10 injured in blast , including some police officers , firefighters . NEW : NEW YORK woman died from cardiac arrest , mayor says . No asbestos in air , but it was detected in 10 of At least 44 samples of dust , debris . the Metropolitan Transportation Authority will continue to test debris .