Drinking Water Safety Is No. 1

Orange County’s dependence on underground aquifers for its drinking water means it must ensure that the ground water is not contaminated by gasoline or other pollutants. The possibility that underground gasoline tanks need closer scrutiny to guard against leakage deserves more discussion.

California’s county district attorneys, who prosecute polluters, supported state legislation requiring the installation of shafts near underground tanks at gas stations. The shafts would test for leaks. But the legislation was defeated last year on the grounds that many counties are not very dependent on aquifer water, getting their water instead from outside sources like the Colorado River.

It is true that installing shafts and operating them would be burdensome, costing gas stations $3,000 or more to install and perhaps $5,000 annually to operate. But if it turns out that the shafts are the best way to detect seepage, that’s money that may have to be spent.

Orange County received a scare last year when officials found that the gasoline additive MTBE, or methyl tertiary butyl ether, had contaminated a well in Yorba Linda. The leak was discovered before the water got as far as household taps, and a deeper well was dug to yield uncontaminated water.

The saga of MTBE is a cautionary tale in the battle to provide clean air and water for Southern Californians. It helps gasoline burn more cleanly and has been credited with dramatically reducing air pollution. But it also has been linked to cancer in laboratory animals and is considered a possible cause of cancer in humans. So Gov. Gray Davis signed an executive order calling for MTBE to be banned by 2002.

Gas stations already have spent large amounts of money to overhaul underground tanks to comply with a recent federal law. But the county Health Care Agency has found some type of surface leakage around more than 40% of the underground tank facilities in Orange County. That raises the possibility of even more leakage underground, where it is difficult to detect.

It will be up to the Board of Supervisors to decide whether an ordinance requiring shafts is necessary, but if the evidence is persuasive, public health will demand the extra protection.