BOSTON -- The cleanup from last week's steam pipe blast in Boston's financial district has been temporarily stopped because the cleanup company doesn't have a proper license.

NewsCenter 5's Jack Harper reported that Boston Fire said Walton Systems of Chelsea is not licensed to remove asbestos.

"The truck was the wrong kind of truck to be doing this in the first place, and also the company was not licensed to do asbestos cleanup," said Boston Fire's Steve McDonald.

The broken pipe's insulation contained asbestos, which was sent high into the air by the explosion.

Walton was hired by LVI Services, a secondary contractor under steam pipe operator Trigen Energy. LVI was also fired. The mayor stopped short of blasting Trigen Energy.

"It is a secondary contractor that had the problem, was not licensed," Mayor Thomas Menino said.

Air quality tests on Wednesday night determined that the air is safe for breathing.

"There is no air-quality issue. The contamination is only in the dirt," Menino said.

Fleet Environmental Services was hired to finish the job.

"Trigen has removed the contactor that was doing the work and replaced them with a new environmental cleanup company. They have been on-site today doing a site assessment to see what equipment they will need to finish the job. At 8 a.m. tomorrow morning, they will resume the cleanup in the manhole," McDonald said.