BALTIMORE (WJZ) — An underground fire erupted below Charles Street in downtown Baltimore near the Inner Harbor for the second time in five months, and BGE crews worked to fix a quarter mile of damaged underground electrical cable.

BGE says its not sure what sparked the flames Sunday night. Witnesses say two manholes exploded but no one was injured.

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“Our crews are in the process of replacing that cable right now. It’s a time-consuming, labor-intensive process,” said company spokesman Justin Mulcahy.

He maintained that BGE equipment was not to blame for the latest fire or another one that started in the same area in February.

“It concerns me when it comes down to the safety of pedestrians or anyone else in the area,” said Michael Rose who works downtown. “It’s really something that needs to be fixed.”

Authorities tested the air for carbon monoxide at businesses nearby. They said the area was safe.

In February, testing showed carbon monoxide levels inside the sub basement of a nearby hotel to be 45 times the level that is considered safe.

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RELATED: Underground Charles Street Fire Raises Concerns, Snarls Traffic

WJZ’s Mike Hellgren spoke to Mayor Catherine Pugh from the U.S. Conference of Mayors in Boston, which she was attending. Pugh said aging infrastructure was one of the big topics she discussed with fellow mayors from around the country.

“We know we’re under federal mandate to fix our infrastructure, but what has not happened is federal dollars to come along with that,” Pugh said.

Last year, an underground steam pipe exploded on Eutaw Street near Camden Yards and sent cancer-causing smoke into the air and injured five people.

As for the latest fire, BGE crews were scheduled to work in shifts until they repaired the cable. They’re also looking at wet weather as a possible cause. Portable generators powered stoplights in the area to keep traffic flowing on both Charles and Lombard Streets.

It was down to one lane on Charles Street for much of the afternoon but could fully re-open by rush hour Tuesday.

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