Dive Brief:

• Hurricane Michael was downgraded to a tropical storm Thursday as it surged northeast toward the Carolinas and Virginia, leaving approximately 1.2 million customers in its wake without power, according to the Edison Electric Institute.

• Duke Energy reported almost half a million are without power between North and South Carolina as the storm brings heavy rain and winds to the region. The utility's two coal ash sites in North Carolina that were breached during Hurricane Florence are not a concern "at this time," Megan Henderson, senior communications officer at Duke, told Utility Dive.

• The Waterkeeper Alliance expressed concern about the storm's potential impact on the six coal ash sites in Michael's path through Florida, although Southern Company told Utility Dive its pits are secure. Southern's Florida subsidiary, Gulf Power, reports that power has been restored to 32,000 customers, although over 100,000 remained without power as of Friday morning. 

Dive Insight:

Vulnerable coal ash storage sites remain in the spotlight as hurricane season hits the East Coast this fall.

Michael is the second major weather event to hit North and South Carolina this fall. Hurricane Florence struck the region less than a month ago, spilling coal ash and cutting power to millions.

"Thankfully, we had a couple of weeks between Florence and Michael so that some of the water [near the ash basins] has receded," Henderson said. "And we're not expecting the historic rainfalls that we had during Florence."

Henderson said "initial repairs" are completed on the utility's dam at a cooling lake near the L.V. Sutton plant. The dam was breached after floodwaters from Florence inundated coal ash sites, leaking the waste into Sutton Lake, which then flowed into the nearby Cape Fear River.

Samples taken around the breached dam showed metal contamination did not exceed state regulations, the News & Observer reported, contradicting environmentalists' testing of the same waters.

Another flood at Duke's shuttered H.F. Lee coal plant leaked coal ash into North Carolina's Neuse River. The same site flooded during Hurricane Matthew in 2016, but the utility said the amount of ash spilled at the H.F. Lee site on both occasions was no larger than "the bed of an average pickup truck."

Both sites are located in the eastern part of North Carolina, which Henderson says is mostly experiencing high winds, with flooding largely occurring in the western part of the state. 

Large coal ash spills from Duke and the Tennessee Valley Authority previously led to states and Obama-era federal regulators pushing for more stringent regulations, requiring many utilities to move toward dry, lined storage pits. However, utilities have not always been quick to adapt and some have fought regulations "kicking and screaming," Frank Holleman, senior attorney at the Southern Environmental Law Center told Utility Dive in September.

The Trump Administration in July issued a final rule weakening federal coal ash standards and potentially giving states more flexibility in how they store the waste. In August, the U.S. Court of Appeals sided with environmentalists, saying the Obama administration's coal ash regulations didn't go far enough in protecting consumers. 

Southern Company said its Florida pits remained "steadfast and uncompromised" in compliance with the Obama-era Coal Combustion Rules.

"Thankfully, [Duke doesn't] operate any coal ash basins in Florida," Henderson said.