An underground fire on Monday caused eight manhole covers to blow out of the streets in the Providence Jewelry District.
Two people suffered minor injuries.
National Grid President Tim Horan said officials are investigating what caused the fire, forcing the covers to lift up. He said high carbon monoxide levels were detected at 300 Richmond St., which houses administrative offices for Women and Infants Hospital.
Fire personnel had responded that building for reports of an odor, when the explosions began at about 11 a.m. The surrounding area was evacuated.
"They isolated it to an outside manhole, and we had National Grid respond and they were checking for readings in the manhole, and at that point in time they backed up and we had a small explosion," acting Fire Chief Clarence Cunha said. "They backed off in enough time not to get hurt."
Public Safety Commissioner Steven Pare said two pedestrians suffered minor injuries and were taken to Rhode Island Hospital. He said the situation was under control and that people would be allowed back into their buildings as repairs are made and readings show it is safe.
"There's all kinds of equipment, that's where wehave cable transformers," Horan said."There's all kinds of electrical equipment and that's when our folks will getin there and find out really what took place. "
The underground explosions interrupted the workday for hundreds of people in Jewelry District.
"I was just working at my microscope and suddenly the whole building just shook," said Josh Stabach, a lab worker. "No fire alarms or anything went off in the building, and everyone was wondering what to do."
Cris Monteiro, who runs Providence Community Acupuncture, said her patients continued treatment, but she said her business did take a hit.
"People couldn't get into the Jewelry District. A couple people called us and said, 'I can't get my way in.' Point Street was closed," Monteiro said.
RIPTA notified bus riders that routes 1 and 3 were being detoured around Richmond Street.