(NewsNation) — A series of vandalism reports throughout the country — including a pair of outages in North Carolina that left thousands without power for days — points to vulnerabilities in securing some of the nation’s power grids.

Following an incident last week that caused widespread power outages in North Carolina, NewsNation’s local news affiliate in Raleigh visited two substations and found they were secured by only a chain-link fence and a lock. There were no visible security cameras or guards.

Law enforcement recently has been called to investigate suspected acts of intentional vandalism in areas including Florida and Washington state.

A source previously told NewsNation the Department of Energy was concerned about a similar port incident days later in South Carolina. However, the local sheriff now says the incidents weren’t related and that the gunfire in South Carolina wasn’t directed at a nearby power facility.

Power companies and industry representatives told NewsNation they’re following industry standards and federal guidelines.

Doug Johnson is a spokesman for the Bonneville Power Administration in the Portland area — home to a substation that was damaged late last month.

The person(s) responsible had broken through a security fence and damaged equipment in the substation yard, Johnson said.

“You always know there’s a threat out there,” Johnson told NewsNation. “We’re always looking for ways to further harden the system against sabotage. But for now, we are in compliance with the rules as they exist today.”

New efforts to target power grids could be emerging.

NewsNation reported Thursday about a suspected white supremacist who entered an online chat and shared a file that contained substation locations in the U.S., Canada and Mexico.

Federal authorities warned law enforcement in August about the incident.

The database uses public information from the Department of Homeland Security and shows the exact coordinates of what’s believed to be every substation in the U.S. — including some of those recently struck in North Carolina, Florida and Oregon.

Duke Energy, the company impacted in North Carolina, previously issued the following statement to NewsNation:

We can’t comment on any ongoing legal proceedings or investigations. However, given the nature and scale of our operations, we – alongside federal, state and local law enforcement and security officials and industry partners – are continuously assessing and evolving our measures to protect our critical infrastructure.  That partnership includes helping bring anyone, who damages our system, to justice. 

Duke Energy