CHAPEL HILL — An EPA official praised the town’s response to a gasoline spill off Martin Luther King Jr. Boulevard last week but said residual oil could persist for several weeks.
A ruptured gas tank spilled an unknown amount of gas into Crow Branch Creek overnight Aug. 1. The creek feeds Booker Creek and Eastwood Lake, but no oil reached the lake because of the town’s quick response, officials said.
“A group of true professionals,” U.S. Environmental Protection Agency coordinator Kenneth Rhame said in a letter to the town.
“I was most impressed with their containment efforts,” he continued. “The coordination between the fire department and the city to get heavy equipment, dirt/gravel to construct a underflow dam (which was textbook) and the effort that the fire department put forth to get ahead of the spill and contain it was over and beyond. ... Chapel Hill is fortunate to have such a dedicated fire department.”
The spill occurred at the Family Fare BP station on 1200 block of MLK near Taylor Street after a contractor had dug a hole for a footing for a new canopy, part of a renovation project.
In an interview, Rhame explained that the underground tank sits in a gravel pit under a concrete slab. When it rained, gravel in the exposed pit sloughed to the bottom of the pit and a piece of concrete slab broke off and punctured the tank.
The tank holds 6,000 gallons and has an estimated 3,200 gallons in it at the time of the leak, said Danny Smith, regional supervisor for surface water quality with the state Division of Water Resources, part of the N.C. Department of the Environment and Natural Resources.
“It is not clear how much was released to the pit and from there to the stream,” Smith said Thursday. “That’s part of what we’re trying to investigate.”
A sump pump in the footing hole for the canopy connected to a pipe leading to a town storm drain, according to Julie McClintock, of Friends of Bolin Creek. As the hole filled, the leaked gasoline mixed with the rainwater and the automatic pump pumped the mixture into the stormwater drain discharging into Crow Branch, McClintock wrote on the Friends website, where she also posted photos.
“Crow Branch flows through a number of Chapel Hill neighborhoods, including Old Forest Creek and Coker Hill West and on downstream to Eastwood Lake,” she added. “A policeman noticed the smell of gasoline at around 5 a.m. and shut off the pump.”
Gasoline vapor has the potential to explode, and although it rained, if the vapor had come in contact with an ignition source “it could have been very serious,” said Smith.
The EPA and DENR went out to oversee the containment effort.
Autumn Romanski, a consultant with the Division of Water Resources saw one dead fish along Booker Creek in the North Lakeshore Drive area. But that was the day of the spill, and more fish were reported killed later, she said.
Ingredients in gasoline such as toluene can be toxic to fish and other aquatic life, depending on the concentration in the water, which was still being determined. Another concern is ethanol, which can constitute 10 percent of gas content. It is water soluble, which means it does not float, Rhame said.
Dams set up on Crow Branch and Booker creeks will remain until Chapel Hill gets the “all clear” call from the regulators, town spokeswoman Catherine Lazorko said Thursday.
Drain pipes used to skim oil off the water surface were to be removed Wednesday or Thursday, Rhame said. Absorbent booms will be left a while longer to absorb any additional petroleum.
Since gas floats, Rhame said it can leave a soapy sheen on the shoreline for several weeks as water levels rise and fall.
Smith said it’s too soon to know if anyone will be fined for the spill.
“We’re still gathering all the information, all the facts,” he said. “It is a serious incident; we’re taking it that way.”