UPDATED:  This story now includes additional information about the number of wells installed to remove and monitor gasoline in the groundwater near Nancy Creek, as well as the number of underground storage tank leaks in Georgia.

A leak from an underground storage tank at an Exxon station in Buckhead dumped an unspecified amount of gasoline into Nancy Creek last month. State officials said the spill has been contained and contractors are cleaning up the area to prevent environmental impacts, but the process will take years.

That time frame is typical to clean up petroleum released into the soil and water from leaks in underground storage tanks, which are used by gas stations, governments or businesses to store at least 10% of the total volume of petroleum or hazardous substances underground.

The greatest potential hazard from a leak in an underground storage tank (UST) is gasoline seeping into the soil and contaminating groundwater, the source of drinking water for nearly half of all Americans. As a result, the federal government began regulating USTs in 1984.

The vast majority of underground storage tanks in Georgia are petroleum tanks, said Kevin Chambers, spokesman for the Department of Natural Resources’ Environmental Protection Division, which has oversight of the UST program in Georgia.

Since the Underground Storage Tank Program began, 82,042 USTs have been registered in Georgia. There have been at least 22,735 petroleum underground storage tank cleanups since 1983. More than half involved petroleum releases into the environment. As of October 2019, there are 828 petroleum releases that remain to be closed out or remediated.

A construction worker works on the Peachtree Dunwoody bridge over Nancy Creek on March 23, 2010. John Spink, jspink@ajc.com

Credit: Andria Brooks

icon to expand image

Credit: Andria Brooks

On Sept. 4, the Fulton County Fire Department responded to complaints of gasoline odor and discovered gasoline in Nancy Creek. A 10,000-gallon UST at the West Paces Ferry Exxon had been leaking mid-grade gasoline into the water. It was unclear how long the tank had been leaking, but it has since been emptied and closed, according to EPD officials.

A state contractor used absorbent boom to contain the release and prevent more gasoline from entering the creek. About 1,200 gallons of gasoline have been removed from the site.

“The release has been contained and impacts to the waters of the state are not detectible outside of the containment area,” he said. Inside the containment area, the impact is within quality standards, Chamber said.

Currently two recovery wells designed to remove petroleum vapor, liquid petroleum and contaminated groundwater are installed at the site along with three monitoring wells to track the amount of petroleum in the groundwater, said Chambers.

An interim system is expected to be in place within a week to provide additional control of the gasoline while a more extensive permanent system is being designed and installed, Chambers said. The permanent system will include three additional recovery wells and 10 additional monitoring wells, but it is likely to be several months before the permanent system is fully designed and in place, said state officials.

At nearby Westminster Schools, the smell of gasoline was no longer in the air, and school officials were assured by EPD that the leak did not extend to the campus and there was no reason to alter any campus activities, said school spokesperson Liz Ball.

Since the federal government began regulating USTs in the early 1980s, more than 1.9 million have been closed. Prior to that time, most had been made of steel, a material more likely to corrode over time and leak gasoline or hazardous substances into the environment. Poor installation, operation and maintenance can also result in leaks.

EPD said the cause of this most recent leak was a “failure” in Tank 2, though it was unclear what kind of failure. Cleanup can range from tens of thousands to millions of dollars, according to the Environmental Protection Agency.

The Leaking Underground Storage Tank Trust Fund, financed by a 0.1 cent federal tax on each gallon of gas sold in the country, was created in 1986 to oversee, enforce and pay for cleanups. In 2019, Congress made $55 million from the trust fund available for states to assess and clean up UST releases.

Most states, including Georgia, oversee their own UST programs and have funds outside of federal money to pay for most expenses related to cleanup from leaks in underground storage tanks.