But there is strong financial incentive for companies merely to dispose of produced water. According to Matt Trask, a California energy analyst, cleaning the produced water can cost up to three to five times as much as buying water on the open market -- and sometimes 10 times as much. Thus, in Kern County in 2008, according to state statistics, oil companies pumped 425 million barrels of produced water into underground disposal wells and discarded 200 million barrels into surface evaporation ponds. That amounts to nearly half of the local produced water.

Evaporation ponds and sumps are being gradually eliminated. But Clay Rodgers, an officer with the California Regional Water Quality Control Board's Fresno division, estimates that there are still hundreds of pond "sites" -- containing more than 1,000 individual ponds and sumps -- across Kern County. And none of the ponds receiving oil wastes in Kern County are lined, Rodgers says. From a Google Earth-vantage, one can see these potentially hazardous manmade lakes, often arrayed in rows of four or five. Some ponds occupy a few hundred square feet; others are as large as several acres. Some are dry or hold just a small amount of residual water, but others are brimming with fluid.

The wastewater ponds not only threaten to pollute both surface and groundwater, they also might be dangerous to the health of wildlife and people. But little is known about the health risks. Matt Constantine, the director of the Kern County Environmental Health Services Department, says his agency focuses on produced water only when "there is a referral from the water board or a complaint from the public."

Constantine's agency did clamp down on one huge produced-water disposal site west of Bakersfield, operated by Hondo Chemical, after problems there -- including fires -- got out of control. To get an idea of the problem's scale, he flew a chartered helicopter over the site. In his office last October, he pulls out a thick binder filled with aerial photos, showing several large evaporation ponds, their surfaces various shades of green, blue and black from oil residues. "It is just an absolute mess," says Constantine as he flips through the pages.

The Hondo Chemical site is perched atop the Kern Water Bank, an underground reservoir that supplies water to municipal and agricultural users throughout the valley. "That presents a very significant concern," Constantine says. In 2007, his agency ordered Hondo to cease operations. The Kern County Board of Supervisors has since found Hondo to be in violation of environmental and health regulations and ordered the company to begin remediation. But Constantine says the cleanup is going slowly.

The serious interest in Kern County's heavy oil is emblematic of global changes. With worldwide stocks of the best raw oil -- "light sweet crude" -- dwindling, heavy oil and other "unconventional" fuels are now estimated to hold 80 percent of the remaining petroleum reserves. That's why major oil companies are going for Canada's Athabascan tar sands and the heavy oil deposits of Venezuela's Orinoco and Mexico's Cantarell and Ku-Maloob-Zaap fields.

These once-maligned fuel precursors are the subject of giddy discussion in corporate boardrooms and R&D departments. Alberta's tar sands have recently become this country's leading foreign source of crude oil, surpassing imports from Saudi Arabia. "If the heavy oil and bitumen (or natural asphalt) deposits in the U.S. and Canada are brought to market," says a Houston-based consulting firm, Petroleum Equities Inc., "they would alone satisfy the current demand for oil in both countries for more than 150 years."

But this "unconventional" petroleum carries a host of heightened impacts. The production and refining of a barrel of oil from Alberta's tar sands generates two to three times the amount of carbon emissions as a barrel of conventional crude. Those tar sands operations also generate wastewater ponds similar to the ones in Kern County. Syncrude Canada, a leading producer of tar sands oil, was found guilty in a Canadian court earlier this year of causing the deaths of 1,600 ducks.

Many people don't realize the risks and costs of the oil industry's new direction. In Kern County, Chevron announced in 2008 that it plans to invest nearly $1 billion in the production from its local heavy-oil fields. Meanwhile, produced water generated by various companies can even be found in reeking ponds adjacent to -- and within -- the city of Taft, a hardscrabble, historic oil town atop the Midway-Sunset oilfield. Town streets are named after General Petroleum and Chevron. Near a church, a trickle of oily outflow from one small pond sometimes reaches a dry streambed.

Such problems are seldom covered by local media, including the region's largest newspaper, the Bakersfield Californian, and the biweekly Taft Midway Driller. The Driller's editor, Doug Keeler, says, "If you're a business owner in Taft, you are beholden, either directly or indirectly, to the oil industry. ... We did (a story) three, four, maybe five years ago on a company that was putting water down a well that caused contamination. In newspaper time, that's a really long time (ago)."

Even the local Sierra Club chapter hesitates to delve too deeply into the affairs of the petroleum industry. Lorraine Unger, treasurer and spokeswoman for the group's Kern-Kaweah Chapter, lives in Bakersfield, in an area known as "The Bluff," which has a panoramic view of the Kern River oilfield. Many members of her Sierra Club chapter work for oil companies, and Chevron, she says, is "not so bad, as far as oil companies go."

Unger knows a fair amount about produced water. "They used to run it right through the agricultural ditches," she recalls. "I can see it all from my backyard." But she says her chapter is not terribly concerned about the practice. After all, there are plenty of other local issues to worry about -- air pollution, sprawl, and the poaching of black bears in the Sierra foothills.

"Besides, even if I was concerned about the water, oil is just too big and powerful around here to go after," Unger says. "It puts food on people's tables."

This story was made possible with support from the Kenney Brothers Foundation.

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