KEELER, Calif. — Jack Riley tries to get home when he sees a dust plume rising off Owens Lake, the dry salt pan created by Los Angeles' thirst for Sierra Nevada water. The plume means swirling gray clouds of alkaline dust will soon envelop this little town, making driving dangerous and breathing unpleasant.
"It's like flour," said Riley, a retired Los Angeles Department of Water and Power employee. "I just stay indoors, lock the windows, and hook up to the oxygen."
"Keeler fogs" in Owens Valley are more than a local reminder that Los Angeles drained the ancient saline lake and exposed the salt bed to winter winds. Dust blowing off Owens Lake has become a major nuisance in California's deserts. It is a legacy of Los Angeles' growth into a megalopolis.
40,000 People Affected
Storms whirling out of Owens Valley recently have been found to pose a health hazard to 40,000 people who must breathe the super-fine dust. The dust also interferes with Navy weapons testing at China Lake, impairs visibility in the Antelope Valley and San Bernardino and falls as an abrasive powder 250 miles to the south, in Orange and Riverside counties.
In Keeler, a former mining town on the east shore of the Owens Lake bed, dust storms have been a winter feature almost since Los Angeles water engineers dried up the lake in 1926. But it was only recently that the massive range of the dust storms was measured and the health risk understood.
"It wasn't until June 2, 1987, that I knew there was any danger," said Don Odell, a Lone Pine attorney and member of the Inyo County Grand Jury.
That was the day the U.S. Environmental Protection Agency declared that a risk to health was carried in the harsh mix of fine-grained salt, clay and sulfates that are swept off the lake bed when winds whip through the Owens Valley, a gash of high desert between the Sierra Nevada and the White and Inyo mountains.
The dust can be caustic, can cause bloody noses, watery eyes and irritated lungs, in part because of mining chemicals dumped on the lake bed, according to local doctors and environmental studies.
"When you get a big whiff of that stuff you can really taste it," said Riley, who sleeps with his oxygen bottle.
The worst risk comes from the extremely small size of the dust particles. Smaller than 10 microns in diameter, the particles penetrate farther into the lungs than ordinary dust and become embedded, the EPA says. (A human hair is 100 to 200 microns thick.)
A major change in EPA clean air standards was made after fine dust was linked with higher rates of cancer, lung disorders and depressed immunity. The PM-10 standard, so named because it governs the 10-micron or smaller particles, was set after tests found that inhaling tiny dust particles takes an extra toll on children, the elderly, people with lung diseases and those who breathe mainly through the mouth.
It is the extreme levels of dust that set Owens Valley apart from other areas with a PM-10 problem.
"It's in a class by itself," said Duane Ono, the EPA specialist on Owens Lake dust. "There's nowhere in the country that measures higher concentrations, except during some forest fires."
Spreads Over Wide Area
Fewer than 4,000 people live in the immediate path of most Owens Lake dust flurries. Thousands more drive through the area each day on U.S. 395, entertained by commanding views of the mountains and desert air that on dust-free days is some of the purest in the state.
But in severe wind and dust storms, which can occur more than a dozen times a year, the Owens Lake dust cloud spreads over a wide area of the Mojave Desert.
"Because of the extent of the plumes, the health of an estimated 40,000 people may be affected by this one source," the Great Basin Unified Air Pollution Control District concluded in a December report.
When winds blow from the north, the direction that raises the most dust, the cloud has been measured 25 miles south of Owens Lake at concentrations the EPA says can cause significant harm, the pollution control district report said.
Air Standards Violated
Dust clouds thick enough to exceed federal air pollution limits often reach Ridgecrest and Inyokern, 60 miles away in Kern County, the pollution district report said, and perhaps reach as far south as San Bernardino and Redlands. A 1985 fallout over Orange, San Bernardino and Riverside counties that damaged car finishes was not acid rain, but more likely was Owens Lake dust.
"It is conceivable that under certain conditions, Owens Lake dust may be captured . . . within the jet stream and travel for hundreds or thousands of miles downwind," the district report said.
Bad dust storms also shut down testing at the Navy's China Lake Naval Weapons Center for five to 10 days a year, delays that cost the Navy $5 million. A Navy study of the dust in 1986 found that it frequently reaches the crest of the Sierra Nevada range south of Mt. Whitney; a dust plume was even seen at 13,500 feet, slipping west over the Sierra into the San Joaquin Valley.