Gasoline spills no threat to drinking water

Art Nadler

Monday, July 27, 1998 | 11:36 a.m.

Even though several gasoline-spill sites have been identified throughout Clark County, none poses a threat to the drinking-water supply, state officials say.

Todd Croft, an environmental scientist with the state Division of Environmental Protection, says that 180 service-station sites are being investigated for spills in Southern Nevada.

Of those, about 40 percent have some amount of the controversial fuel additive methyl tertiary butyle ether (MTBE) spreading underground from their tanks.

Additionally, Croft says, about 24 sites have shown large concentrations of MTBE seepage.

A 10-year federal nationwide program to clean up fuel spills from underground storage tanks began in 1988. It ends Dec. 22, Croft says. By that date, service stations must have replaced their leaking underground fuel tanks or have brought them up to new codes.

Last week, Croft told the Health District that ground water near the intersections of Alta Drive and Valley View Boulevard contained MTBE. The fuel additive, seeping from a nearby Circle K convenience store/service station, was used heavily in gasoline throughout Clark County during the winter months from 1988-95.

While MTBE is no longer added to fuel during the winter in Clark County, it still makes up about 1 percent of the oxygenated fuel in the summer.

The Clark County Health District, at 625 Shadow Lane, is holding a public hearing Aug. 27 to discuss a proposed resolution regulating the use of oxygenated MTBE in gasoline. If approved, it would take effect March 1, 1999.

The fuel additive has been shown to produce tumors in laboratory animals exposed to high doses.

MTBE has been detected in Clark County only from the surface to a depth of 30 feet, Croft said. Southern Nevada's well drinking water is drawn from 250 to 2,000 feet below the surface, a supply he said is not in danger of being contaminated.

No MTBE, or any other fuel additive, has been detected in any of Clark County's drinking-water wells, said Brenda Pohlmann, an environmental scientist with the Division of Environmental Protection.

Southern Nevadans draw about 15 percent of their drinking water from wells, Pohlmann said. The rest comes from Lake Mead.

MTBE ground-water contamination has been a serious problem in California. It's been blamed for the closing of Santa Monica drinking-water wells.

Because Southern Nevada's wells are so deep -- and separated by various layers of clay, caliche, silt and sand -- Croft said MTBE or other fuel additives haven't reached the county's drinking-water wells.

In California, he said, drinking-water wells are separated from the surface only by sand. MTBE has been able to permeate the sand and reach the wells.

Croft said people who rely on private well water may be at danger because these wells aren't as deep or inspected as often. There are about 7,000 private wells in Clark County.