NORWALK — Investigators have discovered that fuel from the U.S. Department of Defense's jet fuel tank farm has tainted soil and ground water outside the 50-acre site.
Tests conducted in January revealed fuel in soil and ground water about six feet beyond the southern boundary of the tank farm, said Lt. Col. Pharris D. Johnson, commander of the Defense Department's seven-state Defense Fuel Region West. Several homes and apartment buildings are within a few feet of the tank farm's southern boundary. More testing is scheduled during the next two months.
"We want to determine how far outside of the facility it has spread," Johnson said.
Johnson said the January tests, as well as past tests, indicated that the contamination has not gone deep enough to threaten the city's ground water supply.
Contamination, including the cancer-causing agent benzene, has been detected at depths of about 40 feet. The water companies serving Norwalk draw their water from depths of 240 to 1,250 feet, according to a city report.
Nevertheless, the disclosure worries city officials, who fear that the fuel will contaminate soil and ground water in the residential neighborhoods and park surrounding the tank farm.
"There appears to be more of a threat to adjacent properties than previously thought," Deputy City Manager Dan Keen said. The contamination "is migrating away from the property," he said. "It could be a threat to our ground water, our drinking water supplies."
The tank farm, on the southeast corner of Norwalk Boulevard and Excelsior Drive, has 12 jet fuel storage tanks with a capacity of 38 million gallons. It supplies bases in California and Nevada through a series of government and private pipelines and by truck, Johnson said.
A private firm, Santa Fe Pacific Pipelines Inc., leases about two acres within the tank farm and operates a fuel pump station. It has not been determined whether the spilled fuel came from the Defense Department operation or Santa Fe Pacific's pump station, Johnson said.
Santa Fe Pacific hired Geomatrix Consultants Inc. of Costa Mesa to perform the tests that revealed contaminated soil and water beyond the tank farm boundaries, Johnson said.
Other studies have located four contaminated areas on the tank farm.
Waste oil was discovered four feet below the ground in the southwest portion of the tank farm in tests conducted by Harding Lawson Associates of Tustin. The contamination from the waste oil is in two spots, one about 50 feet in diameter and another about 15 feet in diameter. Benzene was detected, as was lead, which was found in the soil 27 feet below the surface. Relatively high levels of benzene and another solvent also were detected in water samples drawn from a test well at a depth of about 40 feet.
Three other areas on the tank farm are contaminated with spilled fuel. The largest area is about five acres.
In those three areas, contamination was detected in soil samples at depths from 3 feet to 25 feet below the ground, according to a report released last month by Woodward-Clyde Consultants, a Santa Ana firm hired by the Defense Department. Benzene and other toxic compounds used as fuel additives were discovered. Benzene also was found in ground water samples taken at about 32 feet.
The study concludes that the workers at the tank farm and residents who live nearby face no immediate risk.
But Keen, the deputy city manager, is skeptical. "We think it's a bit premature for them to draw those conclusions," he said. "They're going to be doing additional off-site testing."
The contamination has come from spills that have taken place over the years, officials said. The consultants have identified two sizable spills of jet fuel at the tank farm during the 1960s.
The Defense Department also used at least one environmentally unsound practice that has since been abandoned: Until 1982, contaminated water that would accumulate in the fuel tanks would be drained onto the ground. Tainted water is now treated before it is dumped into county sewers, Johnson said.
"Over a period of time, we've all become more environmentally conscious and we've changed the practices of the past," Johnson said.
A pilot cleanup program is under way and a full cleanup effort could begin in several months if the pilot program proves effective, he said.