In the past two weeks, two citizens groups in North Carolina announced plans to sue Chemours, the DuPont spinoff company that now makes GenX , over its release of the chemical from its plant in Fayetteville, North Carolina. The Cape Fear Public Utility Authority issued a letter of intent to sue both Chemours and DuPont last week over violations of the Clean Water Act and the Resource Conservation and Recovery Act over release of GenX into the Cape Fear River, which is a source of drinking water for more than 250,000 people in the Wilmington area. A conservative group called Civitas also announced its intention to sue Chemours over GenX. Both groups must wait at least 60 days after sending the letters before filing a suit.

The lawsuits over PFOA exposed the chemical’s links to several diseases, including kidney and testicular cancer. Like PFOA, also known as C8, GenX is a perfluorinated compound and similarly, was the subject of internal DuPont research showing it poses many of the same health concerns as the original chemical. Also like PFOA, GenX persists indefinitely in the environment.

After years of litigation over PFOA , an industrial toxin used to make Teflon and other non-stick and stain-resistant products, in 2009 DuPont introduced GenX . Now the slippery substitute has followed the path of the molecule it replaced, contaminating water near plants in West Virginia and North Carolina, and attracting its own intense legal interest.

The legal activity adds to the pressure on Chemours over GenX in North Carolina. On July 22, the U.S. attorney in the Eastern District of North Carolina served the North Carolina Department of Environmental Quality with a criminal subpoena to appear before a grand jury on August 22 and supply all records pertaining to the release of GenX into the Cape Fear River.

In West Virginia, where GenX has been found in ground water — though not yet in drinking water — attorney Robert Bilott, who sued DuPont over PFOA contamination, on July 28 issued a stern letter to the West Virginia Department of Environmental Protection requesting information about what the state agency knew about GenX when it allowed DuPont to release the chemical into local waters near the company’s plant in Parkersburg.

Levels of GenX in the waste water released from the plant into local water have been recorded in concentrations as high as 278 parts per billion in some locations, thousands of times higher than the drinking water standards the EPA set for PFOA, which is structurally similar to GenX and expected to have similar biological effects. On several occasions in 2013 and 2014, the levels of GenX in water coming from the Parkersburg plant were also higher than those set by the WVDEP, according to reports DuPont submitted to the WVDEP.

Bilott’s letter, which asked the WVDEP to “take immediate action to protect community drinking water supplies from possible GenX contamination,” echoed another he sent 16 years earlier asking the EPA to regulate PFOA “on the grounds that it ‘may be hazardous to human health and the environment.’” Chasing GenX through the environment and the courts may take just as long. Both chemicals are considered emerging contaminants, meaning they are not regulated under federal statutes, which makes it difficult to force polluters to clean them up. The EPA’s drinking water advisories for PFOA are voluntary rather than mandatory.

And the chemical industry seems to remain several steps ahead of regulators. After spinning off its “performance chemicals” division, DuPont settled the class action suit over PFOA for $671 million in February. DuPont is poised to merge with Dow at the end of August.

While the EPA has been slowly turning its attention to the class of chemicals that includes GenX and PFOA, considering the safety and cleanup of individual toxins one by one, industry has quietly come up with hundreds of replacements, introducing them to the market before they’ve proven to be safe. Although it wasn’t officially introduced until 2009, GenX was being released into the Cape Fear as a byproduct as early as 1980.

In what appears to be an attempt to disrupt this cycle of regrettable substitutions — and speed up the pollutant-by-pollutant approach to tackling their harms — the lawsuit the Cape Fear Public Utility Authority is planning will target several chemicals. A recent study found six similar compounds in the Cape Fear River water, some at levels 100 times that of GenX. The water utility is planning to sue over the release of several of these “GenX pollutants,” as the Notice of Intent to Sue calls them.

Chemours did not respond to repeated requests for comment. A DuPont spokesperson declined to comment, saying that the company had “not been served with a complaint and therefore cannot comment on this matter.”

According to George House, one of the North Carolina utility’s lawyers, it’s the companies’ job to prove their products are safe — not the people’s responsibility to act as guinea pigs. “That’s putting the cart before the horse,” said House. “Why would someone think they can discharge whatever they want and then make the regulating body prove that it’s harmful to stop?”