Tarps, fans mask a noxious Mother Nature

GLENDA ANDERSON; The (Santa Rosa, Calif.) Press Democrat
ANDERSON SPRINGS, Calif.– For years, decaying rocks near her home made entertaining friends outdoors a potentially embarrassing situation for Jackie Felber.
As guests were confronted with a noxious smell that seemed to come out of nowhere, they would typically fall silent, assuming a human source.

Felber would quickly explain that the stench was coming from organic rock deep beneath the scenic, mineral-rich hills above her Northern California home.

“They’re like, ‘Sure,’” Felber said.

Believable or not, Felber was telling the truth.

When they decay, the rocks above her house produce mercaptan, a substance found in skunk glands, decaying wood and feces. It’s also added to propane gas to alert people of leaks, said Lake County Air Pollution Control Officer Robert Reynolds.

Mercaptans are noticeable in minuscule concentrations and unbearable in high doses.

Bombs containing mercaptan gas were detonated in two chain stores in St. Petersburg, Russia, on Monday in what authorities suspect was an effort by competitors to disrupt sales. The gas made at least 77 people ill, none seriously.

But in Anderson Springs, Felber and other residents of the narrow, wooded canyon near The Geysers in western Lake County are breathing easier these days.

The stink released by the rocks appears to be under control, said Reynolds. He said it’s been nearly a year since anyone has complained about an odor that could be traced to the rocks, an indication that the latest effort to confine and filter the odor is working.

As part of a joint effort by Calpine – the region’s prominent geothermal power producer – area residents and the air quality district, tarps were used to seal the ground where the gas was escaping. Solar-powered fans suck the gases through an activated carbon filter, then release them into the air.

“It made a world of difference,” said Santa Rosa business consultant Jeff Gospe, whose in-laws own a home in Anderson Springs. “The situation was intolerable before. It smelled very much like a refinery.”

Still, capping the malodorous situation doesn’t mean Anderson Springs is smell-free. The odor of sulfur dioxide from the hot springs bubbling up at the end of the Anderson Springs canyon remains, but it’s generally noticeable only at that location, Gospe said.

It’s a welcome relief for the canyon’s longtime residents, who were chronically subjected to the rotten-egg smell of hydrogen sulfide escaping from The Geysers steam fields in the early days of energy production.

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