The cleanup in the aftermath of Tuesday's explosion of an underground steam pipe downtown has largely been completed, but officials said work still must be done before repairs on the system can begin.
Crews have worked since Tuesday to clean buildings and parking lots around the explosion site on Eutaw Street between Lombard and Pratt streets after initial environmental tests found low levels of asbestos, officials said.
Many of the underground pipes are insulated with asbestos, which is known to cause cancer if inhaled.
On Friday, crews still were working to thoroughly clean vehicles that had been caked in dust as the ruptured pipe vented scalding steam and blew dirt, asphalt and asbestos into the air.
"We are coordinating with state environmental officials to ensure the necessary cleaning and environmental testing is complete," said Paul Whitmore, a spokesman for Veolia North America, which maintains the underground system, in a statement.
Whitmore said Friday that air quality at the site was "normal." Earlier tests had found "low" levels of asbestos.
"We will continue to monitor air quality for the duration of the clean up and will continue analysis of environmental samples taken near the site," he said.
Once the cleanup is completed, damage assessment and repairs can begin. But on Friday officials had no estimates when that work will start. For now, that stretch of Eutaw remains closed.
The explosion occurred just before the beginning of an Orioles game Tuesday evening and injured five people, damaged several nearby cars and littered the area with dust.
Maryland Department of the Environment-certified asbestos contractors have been at the site of the explosion, and the city health department said it was is working with state partners at the scene.
Asbestos is considered a dangerous substance associated with some forms of cancer and lung-related ailments, but the risk of disease depends on factors including the amount of time and frequency of exposure, according to the Centers for Disease Control and Prevention.
A person with lung or breathing conditions, or who smokes, might be at a higher risk, the agency said.
Such steam pipe explosions are rare but have caused asbestos concerns before. In 1989, a steam pipe in New York City burst releasing a "150-foot geyser of scalding mud and steam" in an incident that killed three people injured 24 others, according to a New York Times report.
In that explosion, asbestos was released into the air and "contaminated many of the surrounding apartment houses and business, according to The Times.
After the recent Baltimore explosion, city police officers who responded to the scene were notified of safety precautions and the possibility of exposure to asbestos, the department said.
Lt. Gene Ryan, president of the local police union in Baltimore, said officers must be notified and follow protocols when they are exposed to hazardous materials, chemicals or blood. He could not recall another time officers were notified about potential asbestos exposure, but had not heard of any concerns from officers.
"I think everything that can be done is being done," he said.
Several police department vehicles affected by debris from the explosion already have been cleaned by Veolia, Ryan said.
People with vehicles in the area when the explosion occurred may contact Veolia through a hotline at 800-793-2269 or to visit Veolia's vehicle response center at the Baltimore Marriott Inner Harbor at Camden Yards, in Salon D, between 8 a.m. and 6 p.m.
Once the area is completely secured and cleaned, Veolia crews will be able to access the site to investigate the age and condition of the pipe, Whitmore said.
Veolia and city transportation and public works officials must repair the utility infrastructure before the street reopens to traffic.
"We're still looking at what needs to be repaired. We're working as expeditiously as we can," said Adrienne Barnes, a city transportation department spokeswoman. She could not say Friday when the section of road would reopen.
Baltimore Sun reporter Meredith Cohn contributed to this story.