Clovis is suing two chemical manufacturing giants over the toxic remains of a farm fumigant found in drinking-water wells around the community of nearly 100,000 people.
The case will be watched closely by other San Joaquin Valley cities also suing over the same contamination. Clean-water advocates fear this powerful and unregulated chemical, which has been linked to cancer, has been in wells throughout the region for years.
The Clovis case is among at least 11 actions filed against Dow Chemical Co. and Shell Oil Co., seeking the cleanup of 1,2,3-trichloropropane, or TCP. The chemical was in farm fumigants last used in the 1980s. The chemicals were injected into the ground to kill tiny worms called nematodes.
TCP has not yet been regulated because technology does not exist to measure it at extremely low levels, state officials say. The chemical is so toxic that it is unsafe to drink at levels far lower than what can currently be detected -- another point of concern for clean-water advocates.
Over the past several years, the chemical has been detected in 18 of Clovis' 35 active municipal wells, officials say. Cleanup might cost millions of dollars.
The city of Livingston in Merced County last year received $9 million to settle its case against the two manufacturers and a distributor, Wilbur-Ellis Co.
Clovis officials said residents should not have to pay for the cleanup, which would involve the use of carbon filters. A court date for the trial is expected to be set later this year.
Dow disagrees with Clovis and will defend its position, said a spokesman at the company's Michigan-based headquarters. He declined further comment because the case is in progress.
Shell officials did not respond to a request for comment.
This is not the first time Dow Chemical and Shell Oil have been sued in the Valley over contamination from fumigants. Fresno, Sanger and Livingston won multimillion-dollar settlements from Dow and Shell in the 1990s over the chemical dibromochloropropane, or DBCP.
Wells in many Valley cities already have carbon filters for DBCP. Engineers say filters would have to be larger and changed more often to filter TCP because the contamination level must be reduced much lower than most chemicals in drinking water.
The California Department of Public Health has a goal of keeping TCP to levels in the parts per trillion, which is 1,000 times lower than the limit set for many chemicals.
The TCP health goal, set by state officials in 2009, is .7 parts per trillion, which cannot yet be accurately measured, officials said. An analogy for perspective: One part per trillion is like one penny among $10 billion.
Scientists say TCP causes cancer in laboratory animals and damages the liver and kidneys in humans. Clean-water advocates say state and federal authorities should be moving faster to protect the public.
"TCP is harmful at extremely low levels," said lawyer Laurel Firestone of the Community Water Center, a nonprofit advocacy group in Visalia. "But it's not regulated. People don't know if they're drinking it or not."
The Department of Public Health's website shows TCP has been detected in many San Joaquin Valley cities, including Fresno. Public Works director Patrick Wiemiller said 31 wells in southeast Fresno have been affected. The city has not filed a lawsuit, but legal action has not been ruled out.
Several Kern County cities await their turn in court. They include Bakersfield, Delano, Lamont, Shafter and Wasco. Most of the cases were filed in the past decade. They have been consolidated in San Bernardino Superior Court.
State records show Kern water systems have more than 100 detections of TCP, by far the greatest number in the state.
But the rest of the Valley's counties also have detections.
Besides Fresno, Kern and Merced, the counties include Tulare, Madera, Kings, Stanislaus and San Joaquin.