Monday numbers: Chapel Hill’s plan to build offices and housing atop a coal ash disposal site

In the 1960s and 1970s, when coal was still king, the UNC power plant in Chapel Hill generated millions of tons of ash, the byproduct of burning the fuel for energy.

Some of that ash had to go somewhere, and that somewhere was 828 Martin Luther King Blvd. on the north side of town. In 1980, the town unknowingly built its police headquarters on that property. But not until 2013 did town officials realize that ash was present. By then, some of it had already escaped. Portions of slopes leading to Bolin Creek and the greenway had eroded, exposing the ash. Soil and groundwater testing showed elevated levels of toxic chemicals associated with coal ash: mercury, Chromium 6 arsenic, barium, lead, beryllium, cobalt, vanadium and selenium.

Some of the ash was removed, but thousands of tons remain, encased below the parking lot.

Now town officials are proposing to build 80,000 square feet of office space and 175 to 250 apartments on top of the ash. Some of the units would be reserved as affordable housing. According to the requirements for the state’s Brownfields program, which oversees redevelopment of polluted sites — all of the apartments must be above the first floor.

There were few rules or records regarding the use of coal ash as fill prior to 1987, according to the NC Department of Environmental Quality. Coal ash used as structural fill was not required to be reported to the state environmental agency until 1994.

It’s unknown how many private and public properties in North Carolina are contaminated with coal ash, because previously the deposits weren’t required to be reported on the deeds. State law now requires owners of land on which more than 1,000 cubic yards of coal ash has been disposed to list that information on property deeds.

Based on limited information, there are at least 71 recorded structural fill sites, according to DEQ. Coal ash underlies parking lots and roads and runways statewide. The material has also been deposited on an untold number of farm fields as a soil amendment and in unlined landfills.

However, capping the ash under pavement doesn’t always keep it contained. In 2020, a sinkhole formed in a parking lot at a car dealership in Mooresville that had been built on top of ash. In 2018, construction for an apartment complex exposed a deposit of ash — about 40,000 tons — just 50 yards from Lake Norman High School, also in Mooresville.

In 2015, DEQ cited Duke Energy and the engineering firm Charah for violations related to erosion at a deposit site at the Asheville Regional Airport. Rain had washed away a dirt layer, exposing the ash. The material was being used to expand airport facilities, including taxiways and road bedding.

At the JS Turner Lumber Yard, which is down the street from the Family Dollar in Weldon, coal ash had been misapplied for more than 10 years. In 2001, state inspectors found that some of the 250,000 cubic yards of coal ash had been dumped outside of approved areas, including within two feet of the seasonal high water table.

Because of the environmental and public health threats posed by the ash, Chapel Hill residents and environmental watchdogs are demanding that it be removed from 828 MLK Blvd., not merely capped. Chapel Hill officials argue that it would be expensive — upward of $16 million — and that excavation could release toxic pollutants into the environment.

The Chapel Hill Town Council will discuss the proposal again on April 27 at 7 p.m.

Among the numbers that could prove relevant to that discussion (except where noted, are for the state as a whole):

60,000 — Quantity, in cubic yards, of coal ash disposed on 4.5 acres of Chapel Hill Police Department site
71 — Number of known coal ash structural fill sites in North Carolina*
9 — Number of airport runways built on known coal ash structural fill sites
3 — Number of race tracks
6 — Number of road projects
23 — Number of parking lots/ fill beneath commercial or industrial buildings
16 — Number of lots at industrial parks
3 — Number of municipal buildings*
1 — Number of churches
0 — Number of houses and apartments
8,858,668 — Minimum tons of coal ash used as structural fill in North Carolina
10,630,402 — That amount in minimum cubic yards

*Includes the Chapel Hill Police Department site, although it is not in the state database

Source: NC Department of Environmental Quality