The EPA said Wednesday it would change rules aimed at protecting Americans from perpetual chemicals in drinking water. The agency plans to extend the compliance deadline to limit two major chemicals and to revoke and reconsider four other regulations.

Last year, the Biden administration issued long-awaited rules setting restrictions in the municipal drinking water system. The rule not only specifies low levels of two most studied permanent chemicals, PFOA and PFO, but also for four other chemicals associated with various adverse health effects.

In addition to removing these four chemicals from the rules, the Trump EPA now says it will provide a drinking water system until 2031 to get rid of PFOA and PFO in supply, two years after the initial deadline for 2029.

“EPA has a mission: to protect human health and the environment,” said Kyla Bennett, director of science policy for nonprofit public employees. “Faced with their mission and everything they should represent.”

“We are following the agency’s standards for protecting Americans from PFOA and PFO in water across the country,” EPA administrator Lee Zeldin said in a press release. “At the same time, we will work to provide common sense flexibility in the form of additional time. This will support water systems across the country, including small systems in rural communities as they work to address these pollutants.”

Thousands of chemicals used in each industrial and consumer product, from nonstick pans to raincoats to fire foams to waterproof furniture protectors. EPA has linked PFA to various health problems in humans with cancer, hormone disorders, reduced fertility, delayed development in children, and reduced vaccine response.

As the name suggests, these chemicals can last in the environment for thousands of years and can establish high concentrations. The study found that almost all Americans have traces of PFA in their blood, and EPA data released earlier this year showed that half of the U.S. population was exposed to PFA in drinking water.

While increasing research has linked forever chemicals to negative human health outcomes, governments have been slow to regulate PFA. In the late 1990s and early 2000s, a series of lawsuits, including a landmark case in West Virginia, exposed how manufacturers of PFAS chemicals allegedly hide the human health impacts of their products on the public and regulators. As a result, major manufacturers of major U.S. chemicals have worked with the government to gradually produce PFOA and PFO, two of the most commonly used chemicals forever use. Instead of giving up on PFA altogether, the industry turned to the alternative chemicals they claimed were safer.

Since then, research has shown that these alternatives may also accumulate in the environment and be harmful to human health. EPA notes that, for example, hexafluoropropane oxide dimers and their ammonium salts appear to linger in the environment in PFOA and PFO. Chemical giant chemicals started using hexafluoropropanan oxide dimer acid to start making a chemical class called GenX, and in 2009 claimed that these chemicals could be used as a "sustainable alternative" to PFOA. Animal studies have shown that oral administration of Genx chemicals may adversely affect the liver, kidney and reproductive system. Biden rules limit GENX allowed in drinking water to $1 trillion (PPT). In a 2016 water test at a water tool in North Carolina, near the chemical facility, the average was 631 ppt, and some samples tested up to 4,500 ppt.