Threshold for harmful chemicals in drinking water lower than thought: Study The study caused a controversy after reports the government delayed its release.

A government study found that chemicals found in drinking water around the country could pose risks to human health at lower levels than the government currently recognizes, potentially opening the door for more states to begin cleaning up or regulating the chemical.

The report released Wednesday by a branch of the Office of Health and Human Services examined a category of chemicals commonly called PFAS that have been used to make non-stick products, firefighting foam and water-repellant coatings.

They've been found in water systems and soil around the country. The most researched types of these chemicals are referred to as PFOA and PFOS, both of which remain in the environment for a long time after they're introduced, raising concerns about the health effects to people living near areas contaminated by the chemicals.

The report found that PFOA and PFOS caused negative health effects in rodents at a lower equivalent level in humans than previously recognized by the EPA. The finding could cause a ripple effect, possibly requiring new rules or laws as states work on cleaning up areas with high levels of the chemicals.

The study reported that the EPA's advisory level of 70 parts per trillion is seven to 10 times higher than when HHS first said it noticed health effects in animals.

The agency that evaluates potentially toxic chemicals also said that drinking fluids or eating food contaminated with the chemicals could potentially increase the risk of cancer, interfere with hormones and the immune system, and affect growth and development of children and infants. But, overall, more research is needed to understand the impacts of all type of chemicals in the PFAS category on human health.

The study did not specifically recommend a new level that is safe for humans but advocacy groups working on this issue said the new data show states and the federal government should act to clean up the chemicals.

"This study confirms that the EPA’s guidelines for PFAS levels in drinking water woefully underestimate risks to human health," Olga Naidenko, senior science advisor at the Environmental Working Group, said in a statement. "We urge EPA to collect and publish all water results showing PFAS contamination at any level, so Americans across the country can take immediate steps to protect themselves and their families."

The Environmental Working Group has estimated that drinking water for 16 million Americans has levels of the chemicals higher than the EPA's recommended limit and that some amount of it has been found in more than 1,500 water systems serving more than 110 million people.

The study was the center of a controversy earlier this year after Politico reported that officials from the Environmental Protection Agency, Pentagon and White House talked about delaying the public release of the report, writing in an email that it would be a "public relations nightmare." Those emails were obtained by the Union of Concerned Scientists through a public records request.

EPA Administrator Scott Pruitt announced in May that the EPA will move to label PFAS chemicals "hazardous" and will look into a maximum level at which the chemicals are safe and provide recommendations to states looking to clean up contaminated sites. The agency held a summit with state officials that generated further controversy after reporters and a member of Congress reported they weren't allowed to attend some of the sessions.

Dealing with PFAS "is one of EPA's top priorities and the agency is committed to continuing to participate in and contribute to a coordinated approach across the federal government," the director of the agency's water office, Peter Grevatt, said in a statement. "Federal agencies are developing a variety of tools, including toxicity values, analytical methods, and treatment options, that can work together to provide states, tribes, local governments, health professionals, and communities with information and solutions to address these chemicals."

Michigan is one state that has been testing for PFAS substances in water systems. The director of the Michigan Department of Environmental Quality said at the EPA summit that the only reason her state has found so much PFAS contamination is that the state is "actively and aggressively looking," according to MichiganLive.com.

An official with Michigan's environmental agency said the state is pleased the report was released and wants EPA to work with state and local governments to set standards for PFAS.

In one site near the airport in Grand Rapids, officials have identified levels of PFAS chemicals in wells between 54 and 461 parts per trillion. The state has also been working with the EPA to test a site of a former tannery where very high levels of PFOS were found in the groundwater.

Democratic Rep. Dan Kildee represents Flint, Michigan, and called for the federal government to release the CDC study earlier and take more action to limit exposure to the chemicals.

"This federal study is deeply concerning because it demonstrates that PFAS chemicals are more dangerous to human health than the EPA has previously acknowledged. The Trump Administration must address PFAS contamination with more urgency. We must ensure that families and veterans exposed to these dangerous chemicals receive the health care and clean-up resources they need," Kildee said in a statement.