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U.S. EPA, LA Regional Water Board endorse Santa Monica water agreement

Release Date: 11/25/2003
Contact Information: Francisco Arcaute, (213) 452-3378 Mark Merchant, (415) 947-4297

Charnock Sub-Basin to be cleaned of petroleum contaminants

LOS ANGELES - A settlement approved November 21, 2003, between the city of Santa Monica and various oil companies has earned the full support of the U.S. Environmental Protection Agency and the Los Angeles Regional Water Quality Control Board. The agreement will restore the Charnock Sub-Basin, a significant source of drinking water to the city.

The agreement will clean up the gasoline additive and potential carcinogen MtBE, or methyl tertiary butyl ether, from the Charnock Sub-Basin and help the city recover damages related to its contaminated drinking water supply. The settlement was approved by the Santa Monica City Council today. Shell Oil Co., ChevronTexaco Corp. and ExxonMobil Corp. will also be parties to the settlement.

Public drinking water supply wells in the Charnock Sub-Basin have been shut down since 1996 when MtBE contamination was discovered. In 1999, the EPA and the LARWQCB ordered the oil companies to supply replacement water to the city of Santa Monica. The cost of water replacement has been more than $3 million a year.

"The U.S. EPA is pleased to have been able to help facilitate this solution to Santa Monica's MtBE problem," said Wayne Nastri, the U.S. EPA's regional administrator in the Pacific Southwest. "This agreement proves that when all levels of government B local, state and federal B work together, we serve the common good and produce a comprehensive solution to a difficult problem."

"The 1996 discovery of MtBE contamination of the Charnock wellfield resulted in a loss of over 6 million gallons per day of water supply - an amount equal to approximately half of the City of Santa Monica’s daily water demand," said Susan Cloke, Chair of the LARWQCB. "Given the ecology of Southern California, it was imperative that this natural water supply be restored. The Regional Board congratulates all the parties on reaching a settlement that protects public health and is good for both water quality and water quantity."

The settlement requires the oil companies to build treatment systems for Charnock water supply wells to remove MtBE as water is pumped out. This will restore the drinking water supply that was shut down in 1996.

This agreement follows seven years of investigation and cleanup under the federal Resource Conservation and Recovery Act and the state's Porter Cologne Act directed by the EPA and the LARWQCB. The MtBE contamination in the area surrounding Santa Monica's drinking water wells came from at least 27 possible sources, most of which were gas stations in the Charnock sub-basin.

"Today's settlement will ensure that all of the contamination is cleaned up and the ground water can once again be used for drinking water," Nastri added.

Prior to today's settlement, the EPA and the LARWQCB had already achieved significant cleanup in the Charnock sub-basin. The agencies have identified 27 sites that had released MtBE to soil and 12 sites that had released MtBE to groundwater. In addition, EPA and the LARWQCB orders have required payments to the City in excess of $13 million in water replacement costs. And the oil companies have extracted more than 250 million gallons of contaminated groundwater, removed over 4,000 cubic yards of contaminated soil and approximately 6,000 pounds of MtBE from the Charnock Sub-Basin.

MtBE was first introduced in 1979 to make gasoline burn more cleanly; however, it has become a concern because of leaks into drinking water supplies. In addition to being a possible carcinogen , MtBE is very soluble in water and tends to spread further and degrade more slowly than other gasoline components.

California will phase out MtBE by the end of this year.

For more information on the Charnock site visit