Attacks on 4 Washington Substations Cut Power to Thousands, Officials Say

Local authorities in Washington State are investigating a series of Christmas Day attacks on four power substations that knocked out power to thousands of customers in the region and have raised concerns once again about the security of the nation’s power grid.

The attacks come just weeks after two substations in North Carolina were damaged by assailants who disabled equipment with gunfire, leaving about 45,000 customers in rural Moore County without power for days. Those attacks highlighted growing concerns that the power grid could be a target for extremist groups and prompted federal regulators to order a review of security standards for the nation’s power grid.

The authorities in Pierce County, Wash., said that they had no suspects and were still in the early stages of their investigation.

“At this time, deputies are conducting the initial investigation” the Pierce County Sheriff’s Department said in a statement. “We do not have any suspects in custody. It is unknown if there are any motives or if this was a coordinated attack on the power systems.”

According to the sheriff’s department, the first attack occurred sometime before 5:30 a.m. on Sunday, when officers received a call that a Tacoma Public Utilities substation about 20 miles south of downtown Tacoma, had been broken into.

“Nothing had been taken from the substation, but the suspect vandalized the equipment causing a power outage,” the sheriff’s department said. The authorities said that they were soon notified of a second break-in at another substation, just over 2.5 miles east.

Tacoma Power, which manages both substations, said that after the attack, more than 7,000 customers in the regions of Elk Plain and Graham were without power. “Earlier this month, we were alerted by federal law enforcement of a security alert for the electrical grid,” the utility company said in a statement, adding that it could not share any further details about its security tactics or the attacks.

Late on Sunday morning, Puget Sound Energy notified the authorities that it had also experienced a power failure just before 2:40 a.m. that day. The sheriff’s department said it confirmed that the third substation had also been broken into and vandalized.

That evening, just after 7:20 p.m., dispatchers were notified of a fire at a second Puget Sound Energy substation, which the sheriff’s department said had been caused by a vandal and knocked out power to homes in the area.

The utility said it was coordinating with the authorities and could not comment further on the investigation. “P.S.E. has extensive measures to monitor, protect and minimize the risk to our equipment and infrastructure,” the utility company wrote in an email on Monday, adding that power to all affected customers had since been restored.

Sheriff’s department officials did not immediately respond to requests for further comment on Monday, but a dispatcher said by phone that the F.B.I. was now leading the investigation into the attacks.

The Seattle office of the F.B.I. said that while it was “aware of the reports,” it could not confirm whether or not the agency was looking into them.

“We routinely share information with our local partners and take threats against our infrastructure seriously,” Steve Bernd, a spokesman for the F.B.I., wrote in an email on Monday evening. “We urge anyone with information to contact law enforcement.”

The F.B.I. has confirmed that it is investigating the Dec. 3 gunfire attacks on the power grid in Moore County, N.C.

Gov. Roy Cooper said after the attacks in North Carolina that whoever carried out the assault “knew exactly what they were doing,” and that the episode had drawn attention to the importance of protecting critical infrastructure.