Cause of underground blast in downtown Albany not yet found

PHOTOGRAPHER: Steven Cook

National Grid workers are expected to continue to work into next week repairing damage caused by an underground explosion Wednesday, a company spokesman said.

What caused the blast, and whether any lessons learned could apply to similar lines elsewhere in the Capital Region, won’t be known for several days, Patrick Stella said.

Workers removed most of the burnt cable by Thursday, Stella said, and the area is safe. Crews now have turned to replacing the cable, which could take into next week.

The explosion happened around 3 p.m. Wednesday on a section of North Pearl Street near Steuben Street. A surveillance video released by the Albany County Sheriff’s Department showed a ball of fire suddenly coming from underground.

No injuries were reported, and electrical service remained uninterrupted throughout. The incident did cause road closures, however, and the Albany County Judicial Center was shut down for the day after the building’s air intake system drew smoke into the structure.

Also, some manhole covers were blown off, but Stella said those were heavy and didn’t go far.

All the roads reopened by Thursday. Work to replace the line is expected to halt over the weekend, Stella said, so not to disrupt a music festival in the area.

As for the blast itself, Stella said it was caused by ignition by unknown means of flammable gas that collects naturally in the underground line vaults.

Sewer gas and other gases can often be found there, but sparks are not. The task of the investigation is to determine where the spark came from, Stella said.

“That’s our next step, to do a full investigation,” Stella said. “It could take several weeks. There are a lot of different facilities in those vaults.”

Power wasn’t interrupted because there are four redundant lines in the area, and the other lines took up the slack, Stella said. Also, National Grid’s monitoring system detected a problem around the time of the blast, and crews were on their way before being formally notified of the explosion.

The investigation is being done in part to see if any problems exist and need to be fixed, as Stella noted similar underground vaults exist in Schenectady and Troy. If company personnel find anything that applies to the other systems, they would be able to fix those, as well, he said.