Buried fuel tanks raise a host of concerns in VUSD

By: ROB O'DELL - Staff Writer | Saturday, April 9, 2005 10:33 PM PDT ∞

VISTA ---- They are everywhere, but they only pose a problem when they leak. Underground gas storage tanks are prevalent in the county, drawing attention only when they must be removed or repaired, experts said last week.

The Vista Unified School District disclosed Thursday that it had removed three leaking tanks more than eight years ago from a site near the district's grounds department at 1222 Arcadia Ave.

Two days earlier, the district hired a company to test the air and soil around the facility after several employees voiced concerns that six workers in the 20-person department had been diagnosed with cancer since 1998.

Threat to water

To be sure, leaking gas tanks don't automatically cause health problems ---- including cancer.

Leaking tanks are most dangerous when their fuel seeps into drinking water, said Mark McPherson, chief of land and water quality at the San Diego County Department of Environmental Health.

Because gasoline contains benzene, a known carcinogen, and MTBE, a gasoline additive that is a suspected carcinogen, the risk of contaminating a drinking water supply is the most serious problem posed by a leaking tank, he said.

A leaking tank can also pose health problems if gas vapors migrate into buildings and enclosed spaces, he said. People who are chronically exposed to high concentrations of vapors are at the greatest risk, McPherson said.

District officials said last week that most employees in the grounds department do not spend significant amounts of their workday at the Arcadia Avenue site, but are spread throughout the district.

Risk was less

Because the school district imports water from the Vista Irrigation District, it is unlikely the water supply posed a risk at the Arcadia site, McPherson said.

"You would have substantially less risk," with imported water over well water, McPherson said. "Vapors can cause a risk. Of course, it would have to be concentrated, and the exposure tends to be more chronic than acute (when it is harmful)."

Carol Spangenberg, project manager of the cleanup for the Department of Environmental Health, said the primary source of contamination at the Arcadia site was removed in 1996 when a contractor dug up three of the four tanks ---- two underground fuel tanks of 4,000 gallons and a third of 2,000 gallons.

A secondary source of contamination was taken away when a contractor removed 75 cubic yards of contaminated soil in 1996 and 1997, enough to fill two living rooms with dirt.

"The main source of the contamination was removed 10 years ago," Spangenberg said, adding that she felt ready to close the case file, pending the installation of some monitoring wells between the site and nearby Buena Vista Creek.

Widespread leaks

The county has opened more than 3,000 cases of leaking tanks in San Diego County since 1988, McPherson said, of which 1,994 were resolved while 963 remain open.

"Underground fuel tanks are everywhere," said Sue Pease, an environmental scientist with the Regional Water Quality Control Board.

In Vista, there have been underground tanks found in several places around City Hall and near the city library at Escondido and Eucalyptus avenues.

Three of those ---- two 4,000-gallon tanks and one 2,000-gallon tank ---- were off Eucalyptus Avenue, between the City Hall and library sites. Those tanks were removed when City Hall opened in 1979 and the school district moved its operations to its current site.

A 1,000-gallon fuel tank was found under the tennis courts behind City Hall in 1998 that was left from the time the complex served as Lincoln Middle School and a bus-fueling station.

Setting standards

When preparing to construct Vista Village Drive from Vista Way to Escondido Avenue, the city also found contamination of the soil along Vista Way near Recreation Drive that could have been caused by a fuel tank.

The problem with underground tanks is ensuring that they meet standards, and therefore will not break down and leak, experts said. In 1998, the Environmental Protection Agency began strictly enforcing 10-year-old guidelines that required the hulls of underground gas tanks be doubled to ensure they didn't leak.

Spangenberg said that often the tanks are dug up because the owners would rather drain and remove them than bear the expense of upgrading them to meet standards.

There are more costs involved when the tanks are found to be leaking and have contaminated soil and the water supply, experts said.

Pease said the first priority when examining a leaking tank is to determine whether gas has leaked into the water supply, and if it had, to set up monitoring wells. Only after the site assessment is done and there is no more work to be done on the water supply, do experts test for vapors, she said.

They have history

The gas tanks at the Arcadia Avenue site date to the 1960s, when the property was first a county maintenance site, then became a city maintenance site.

Jack Larimer, museum director for the Vista Historical Society, said that the site became city property in 1963. The school district acquired the land in 1979, he said, when the district and the city traded properties in a deal that provided Vista with its current City Hall on Escondido Avenue.

"Originally, that's what the county used as the main (maintenance) yard, and the city took it over when it incorporated (in 1963)," Larimer said.

The county assessor's office also found property appraisals in the 1960s that listed the former owner as both the county and the city. The first records of the gas tanks date to 1965, according to state records filed in 1988.

Things in storage

Rob Christ, the school district's manager who oversees the grounds department, said the tanks were used as storage for gas pumps that the district used to fuel buses. He said at least one tank contained diesel fuel.

Discussion of the leaking tanks arose after workers aired concerns about six grounds department employees who were diagnosed with cancer ---- most of them with different types.

The Centers for Disease Control and Prevention defines a cancer cluster as "more likely to be genuine if the cases consist of one type of cancer, a rare type of cancer, or a type of cancer that is not usually found in an age group."

Jim Sheldon, a lead groundskeeper, said all six of the men who have been diagnosed with cancer had been on the site in one capacity or another in 1996 when the tanks were removed, and some of them had been employed for a long time before that.

Contact staff writer Rob O'Dell at (760) 631-6620 or rodell@nctimes.com.

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