An steam pipe explosion at Fifth Avenue and 21st Street in Manhattan sent clouds of vapor into the air this morning around 6:30 a.m., and caused over two dozen nearby buildings to be evacuated. Five minor injuries have been reported.

While the source of the explosion is still under investigation, city officials say the pipe was lined with asbestos. Those in the area at the time of the blast are encouraged by Con Edison to bag their clothes and shower; the FDNY has already decontaminated 100 first responders a few blocks from the scene.

The cause of the explosion is still unknown. At a press conference this afternoon, Mayor Bill de Blasio said it will be a few days before residents of the affected area can return. According to the mayor, there had not been any recent work done around the site.

De Blasio said there had been no reports of serious injuries, but confirmed that asbestos was in fact found in the steam line casing. He called it a "real concern," but said air quality in the area was safe.

"Our concern is the debris that was thrown off by the rupture, some of that is still visible on the street and on the buildings' facades. That all needs to be cleaned up. There's going to be a thorough assessment to make sure all the buildings are clean and safe," de Blasio said.

He added that the area will continue to be closed off for the next few days, but that this timeline was subject to change. 28 buildings in the area are of "greatest concern," but overall, 49 buildings will need to be examined before normal functionality can be resumed. "We're not gonna cut any corners, we're gonna be very thorough," the Mayor said.

De Blasio was quick to reassure New Yorkers that "brief exposure [to asbestos] is not a problem... but if this material is in a building, if it's on clothing, that is a real concern." He urged anyone who was in the vicinity of the explosion to remove their clothes and shower immediately.

"Thank God this happened so early in the morning," de Blasio said, mentioning that the outcome could have been much different had the explosion occurred just a few hours later during the morning rush hour.

The steam pipe in question was 86 years old, the NY Times reports. De Blasio said much of the asbestos present in city steam lines has been removed in recent years—but not all, apparently.

Fifth Avenue between 19th and 22nd Street remains closed to traffic, and de Blasio said he expected that to be the case for the next few days.

Looking at photos of the explosion and the aftermath, one can understand why this might take a couple days to clean up, especially considering the asbestos.

But as always, New Yorkers didn't let something as inconsequential as a little steam stop them from getting to work:

While this steam pipe explosion didn't cause any major injuries, it's worth noting that two similar explosions in the past weren't nearly as harmless.

In 1989, Con Edison crews shattered a pipe with a jackhammer on Gramercy Park South and 20th Street, killing two workers and a resident.

And in July of 2007, another steam pipe exploded near Grand Central, killing one woman and injuring dozens more.