NEW YORK (AP) – Tests showed an underground steam pipe explosion did not leave asbestos in the air, but the chemical was found in some solid debris and dust that settled after the blast, the city Office of Emergency Management said.

Tests were continuing, but the agency said in a statement that long-term health problems were “unlikely.”

Mayor Bloomberg had said the possibility of asbestos contamination was the main health worry after the blast Wednesday evening, which left a gaping crater less than a block from Grand Central Terminal in midtown Manhattan. Some pipes carrying steam through the city are wrapped in asbestos, a chemical commonly used until the mid-1970s in insulation and fireproofing material. Its tiny fibers can cause cancer and other ailments when inhaled over many years, according to the city Department of Health and Mental Hygiene.

Officials took eight air samples Wednesday night in the area around the explosion, and none came back positive for asbestos, the emergency-management agency said. But asbestos was found in six of 10 samples of debris and settled dust.

The agency was conducting more tests to determine the extent of the contamination, but the statement said any exposures to asbestos would have been brief and the health risks limited.

“Developing an asbestos-related illness after being exposed for a short time – even at high levels – is very unlikely,” the agency said.
Several blocks around the site of the explosion remained cordoned off early Thursday as trained workers began cleaning up the dirt and debris, the agency said.

Residents who were already in the area were allowed to stay, but the city told them to keep windows closed and air conditioners set to recirculate indoor air instead of drawing it from outside. Anyone exposed to the falling debris was instructed to wash carefully and isolate soiled clothing in plastic bags.