DuPont's installation of a water filtration system at Little Hocking Water Association is not enough to adequately protect the public from C8 and other related chemicals that taint the local water system, according to a federal lawsuit recently filed in Columbus.

The water association is asking the court to order DuPont to fund a comprehensive cleanup of all affected well fields and an investigation, assessment and cleanup or containment of all sources of contamination. The suit also seeks unspecified compensation for damages.

DuPont officials say the complaint is without merit.

The U.S. Environmental Protection Agency considers C8 and related chemicals as "a likely carcinogen." Other ongoing health studies suspect prolonged exposure may contribute to elevated cholesterol, difficulty conceiving, weakened immune systems and birth defects, according to the lawsuit.

C8, also known as perfluorooctanoic acid or PFOA, has been used at the Washington Works plant, located in Washington, W.Va., directly across the Ohio River from Little Hocking, in the Teflon-manufacturing process since the 1950s.

DuPont maintains the chemical has no known human health effects.

Little Hocking Water Association provides water to an estimated 12,000 individuals at homes, schools and businesses in eight townships in Washington County and two Athens County townships.

C8 was detected in the water supplies of six area water districts, including Belpre and Little Hocking, in 2002, leading to a class-action lawsuit. The settlement of the lawsuit resulted in the creation of a science panel to study the chemical and DuPont providing filtration systems for the affected water districts.

The Little Hocking filtration system went into effect in November 2007.

In the past, DuPont officials have said the filtration systems have been "effective and efficient" and C8 levels in those systems are below the allowable community exposure standards for the chemical.

However, the lawsuit alleges the allowable exposure standards should not apply in Little Hocking because of chronic exposure. The levels of C8 and other related DuPont chemicals recorded in the water system and in blood samples of its users is considerably higher than any other population.

"The average level of PFOA in the blood of people in the United States is 5.6 ppb," according to the suit. Residents in the Little Hocking water system ranges from 112 ppb to 1,950 ppb, the suit alleges.

"Both the negotiated (0.5 ppb action level) and the newer (0.4 ppb) action level are inadequate levels based on sub-chronic exposure," the suit alleges. "Neither level protects Little Hocking's water users, who have been chronically exposed."

The concern, according to the suit, is that PFOA is continuing to accumulate in the blood of area residents.

In an effort to account for chronic lifetime exposure, independent scientists at the New Jersey Department of Environmental Protection identified a PFOA drinking water guidance value of 0.04 ppb, an order (10 times) lower than the current standards, according to the suit.

DuPont officials offered a written statement in response to the suit.

"We have received the complaint that was filed in federal court in Ohio by Little Hocking Water Association Inc. We believe that the allegations in the complaint are without merit. We will vigorously defend the case," said Robin Ollis Stemple, DuPont spokeswoman in a written response.

Little Hocking Water Association General Manager Robert Griffin referred all questions about the suit to the association's attorney, David Altman, of Cincinnati. Altman did not return a call seeking comment.

It was not immediately clear what the current levels of PFOA are after filtration in the water system.

The suit, assigned to Judge George Smith, was filed Nov. 27 in U.S. District Court of Southern District of Ohio.