The coal-ash story keeps coming closer to home.

It began last December across the Blue Ridge in eastern Tennessee, when a TVA power plant's coal-ash impoundment -- a low dam holding back millions of cubic yards of dirty power-plant leftovers -- failed. The resulting spill sent slurried ash coursing over hundreds of acres, destroying homes and racking up hundreds of millions of dollars in cleanup costs.

In June we learned that of the 44 such impoundments around the nation that the Environmental Protection Agency is most concerned about, 12, or more than a quarter, are in North Carolina.

Now the EPA has announced that on a lengthy list of impoundment sites studied this summer by engineering consultants, one of the two that received a "poor" rating is a Triangle neighbor. (There's one worse rating category, "unsatisfactory," which no site got.)

The local site is Raleigh-based Progress Energy's Cape Fear Plant, a 400-megawatt coal-fired electricity generating station on the Chatham and Lee county line, where the Deep and Haw rivers converge to form the Cape Fear. The plant is surrounded by dozens of acres of holding basins for coal- and fly-ash wastes generated by the combustion and pollution-control process. According to a thorough study by private engineering consultants, some of the retaining walls are cause for concern.

That's noteworthy, and requires more study if not immediate remedial action. Still, the EPA isn't saying the sky is falling, or that all these dams are about to burst. In some cases, a negative rating simply means that appropriate records can't be found. That may be the main story at another Progress Energy coal-fired plant near Asheville, which also got a "poor" rating. At the Cape Fear Plant, much of the muck seems to be pretty well solidified after years in the pits.

But as the December spill at the TVA's Kingston Fossil Plant showed, vigilance is essential, since the consequences of inattention can be severe. The best thing that's happened to coal-ash impoundments is a new and badly needed North Carolina law, passed by the legislature this summer with support from Gov. Beverly Perdue, that will require state inspection of these holding basins as if they were regular dams.

Previously, and almost unbelievably, the only required impoundment inspections were furnished by private engineers every five years. Now the state will do the checking under its Dam Safety Act, every two years.

Coal-burning utilities tout the usefulness of coal ash and defend the previous "third party" inspection setup (which might be partly responsible for the "poor" ratings in our state). It's true that ash does have some commercial uses, in strengthening concrete, for example. Yet the overwhelming bulk of this debris isn't going anywhere near new buildings or bridges -- there's simply too much of it -- and frequent, state agency inspections are the best assurance that it will stay where it's put.

The situation that generated North Carolina's new legislation has been an eye-opener. The public has long been aware of coal plants' air pollution effects and the depths of despoliation that mining has brought to the Appalachians. Now we've become aware of yet another downside to burning coal, which is both the cheapest fuel and one of the costliest.