Even before the state began to require tests of underground tanks in 1984, Ashland Chemical Co. in Santa Fe Springs was keenly aware of the hidden threat such tanks pose.
Ashland, part of an earlier state testing program for large companies, discovered in 1983 that toxic industrial solvents stored in several of its 47 buried tanks on Painter Avenue had leaked into the ground water.
Since then, the company has spent $1 million in an unsuccessful attempt to find the boundaries of the plume of contaminated water and is facing a cleanup expected to cost millions of dollars more.
The Ashland leak case is one of 160 discovered throughout the Southeast area since 1983, when owners of 4,000 to 5,000 subterranean tanks began to test and permanently monitor them as required by state law.
Quick Cleanup Important
Leaks in about 40% of those cases have contaminated ground water with fuels or solvents. Quick leak detection and cleanup are important, water officials say, because delays allow contaminants to spread, increasing costs and the chance that toxic chemicals will sink into deep drinking-water basins.
In the Southeast area, 20 municipal wells and at least three smaller public wells have been closed and 80 other wells are contaminated to a lesser degree.
How much leaking tanks have contributed to the industrial Southeast's well-contamination problem is unclear, but state officials say ruptured tanks are probably a main source of the pollution.
In the Ashland case, test wells dug into the top two regional aquifers beneath the plant revealed low-level solvent contamination, the company said. Both aquifers supply limited drinking water elsewhere in the Southeast area, but Ashland's pollutants are not an immediate threat to those water wells. Three deeper water basins that supply much of the area's well water have not been tested.
Los Angeles County officials who oversee tank testing for Southeast cities say the number of leaks detected in the area could soar during the next year as the county presses owners to test and monitor their tanks by a mid-1989 deadline.
Even now, "we've got (leaks) all over the place. I don't even keep them in my head anymore. There's too many of them," Carl Sjoberg, director of the county tank-inspection program, said in a recent interview.
To prove his point, he culled five Southeast cases from a batch of 1988 leak reports.
In South Gate, he said, a layer of gasoline three feet thick was found floating on ground water beneath an oil-company terminal.
5 1/2-Foot Gasoline Layer
In Santa Fe Springs, layers of gasoline up to 5 1/2 feet thick were discovered under two service stations.
In La Mirada, fuel "several feet" deep was detected at another gasoline station.
And in Cerritos, a highly toxic degreasing solvent had leaked from a tank at a small business into the ground water.
Through the end of July, 20 leak cases had been reported in Commerce, more than in any other Southeast city. Whittier and Santa Fe Springs had 19 each, Vernon 13, South Gate and Montebello 11 each, and Downey 10. A total of 57 leaks were reported in other area cities.
Countywide, about 30% of underground tanks have been tested and also comply with local ordinances that require electronic monitoring to detect new leaks.
5 Cities Enforce Laws
This compares with 80% compliance in Long Beach and Vernon, which with Torrance, Santa Monica and Los Angeles are the only cities in the county that chose to enforce tank laws themselves. The county runs the tank program in unincorporated areas and in 80 other cities.
Ground-water cleanups are supervised by the state Regional Water Quality Control Board in Los Angeles.
Los Angeles County has been slower to enforce tank laws than other counties and some cities, Sjoberg said, partly because its fire department, which protects 43 cities, had no inventory of tanks when the state law was passed. A 1984 state-supplied inventory did not include about 15,000 of the 33,000 tanks then in the county's jurisdiction, he said.
New Tanks Discovered
"We're still finding tanks," he said. "Every time I drive down the street I spot a place that's not on our list. A (tank owner) came in the other day and said, 'Hey, I just found nine more.' "
Sjoberg said many companies simply dug up their tanks rather than test and monitor them, or removed the tanks when leaks were found, instead of replacing them with mandated double-walled containers.
About 10,000 have been removed and not replaced in the county's jurisdiction, Sjoberg estimated.
The closure of wells in several Southeast cities illustrates the problems tank leaks may cause.
For example, South Gate officials say solvent leaks, perhaps from below-ground waste-water basins now being tested, have contaminated half the city's water supply. The city plans to build a $5-million plant to clean the water from five closed wells. For now, the city must buy costly imported water to meet its needs.
25% of Wells Contaminated