Raleigh, N.C. — On Sept. 29, contractors installed a fix for what they believe was the source of the three fuel spills at Central Prison this year. The state may fine the prison for polluting local surface waters.
The fuel came from an underground spill first noticed leaking into Rocky Branch Creek in August 1998. A buried fuel line near the northeast corner of the maximum security building (roughly 200 yards from the stream) had a “pinhole” leak, according to a 2012 summary written by Mid-Atlantic Associates, the environmental consulting firm that completed the initial site assessment in 1999.
The spills this year occurred after heavy rain, draining to the creek, which leads directly to the Neuse River. Fuel spilled into Rocky Branch in February or March and then again in September, following big rain storms.
The “ephemeral nature” of the fuel leaks made them difficult to diagnose, said Bill Stovall, director of engineering at the Department of Public Safety. “We think we found the entry point for the fuel product that was getting into the storm drain system.”
That fuel line was connected to an 8,000-gallon fuel tank installed in 1981.
In 1999, environmental consultants installed a trench and recovery well system. As the petroleum and ground water move downhill, the trench directs it to wells that hold the oil.
The test well nearest the original spill has been the most active during the past 13 years. The wells have been inspected quarterly, on average. Often, no oil was removed; occasionally a gallon or two of oil-water mix was pumped out. On some occasions, a larger quantity was found, reports from Mid-Atlantic show.
The amount of oil being recovered had lessened, and prison officials were hopeful they could close the case.
Mid-Atlantic’s report from June of this year states that on Jan. 25, representatives of the North Carolina Department of Public Safety and Mid-Atlantic recommended closing the site. DENR recommended pumping the well nearest the spill site, completing soil sampling and inspections at the site, and testing the water for evidence of petroleum.
Then in February, fuel showed up again in Rocky Branch Creek. In April, 23 gallons of oil were removed from the well nearest the spill. Fuel was in the creek again in March and September.
Consultants believe that heavy rains were pushing fuel along an underground pipe and into a catch basin. The catch basin congregates several storm water drain pipes that then flow into the storm sewer and the creek.
Consultants removed a 12-foot cube of contaminated soil, sealed the basin, and filled it with gravel to trap and direct oil. DENR and Mid-Atlantic agreed that this solution was the best, according to Stovall. Now, he said, DPS “will need to monitor for a while yet. After some reasonable period of time we would be in a position to close out that remediation effort.”
Though, he said, they didn’t know how much fuel was still in the ground. September’s remediation cost around $15,000. The prison has spent more than $270,000 since 1999 on the spill. Still considerably less, Stovall said, than the cost would have been to remove spilled fuel from underneath the maximum security building on the prison site.
Danny Smith, surface water supervisor with the state Division of Water Quality, said that his division could still recommend fines.
“I would draft a case and forward it to our central office to be reviewed and assessed,” he said.
Then the Department of Public Safety could either appeal or pay the fines. All proceeds from DENR fines go to the public school system.
“We are reviewing that issue and want to do some follow up visits when we get some weather,” Smith said.