Although it was too late for him to benefit, Daniel Kinel felt relieved in December when the Environmental Protection Agency finally banned TCE. The compound, which has been used for dry cleaning, manufacturing and degreasing machines, can cause cancer, organ damage and a potentially fatal heart defect in babies, according to independent studies and the EPA. It has also been shown to greatly increase people’s chances of developing Parkinson’s disease.

Kinel and three of his colleagues were diagnosed with Parkinson’s disease. They all worked in a law office in Rochester, New York, that sat next to a dry cleaner that had dumped TCE into the soil. Kinel was diagnosed with the neurodegenerative condition at age 43, after working there for seven years. His three colleagues have since died. At least 15 of the firm’s partners developed cancers related to TCE.

“It felt good that we were finally getting rid of this terrible chemical,” said Kinel, whose symptoms now make it impossible to type, write or work as a lawyer. “My children and grandchildren would be protected.”

But his feeling of solace has been short-lived.

The ban has been challenged on multiple fronts since President Donald Trump assumed office for a second time in January. Republicans in the Senate and House introduced resolutions to repeal the ban, which was vulnerable to being overturned through the Congressional Review Act because it was issued shortly before the inauguration. Meanwhile, companies and trade groups have sued to stop the ban in court. A Trump executive order delayed the implementation of the ban until March 21. And last week, the EPA asked a federal appeals court to further delay the ban until the end of May.

TCE, short for trichloroethylene, is one of five toxic substances for which full or partial bans put in place by the EPA under President Joe Biden are now under threat. The Trump administration told the courts that it wants to review all five bans to determine whether they should be rolled back. Those banned substances include a deadly paint stripper called methylene chloride; PCE, a solvent that’s similar to TCE; carbon tetrachloride, which is used as a cleaning fluid; and the cancer-causing mineral asbestos. David Fotouhi, the lawyer Trump nominated to be second-in-command of the agency, tried to overturn the asbestos ban in October, when he was serving as an attorney for a group of car companies. The EPA classifies all of the recently banned chemicals as either carcinogenic or probably carcinogenic to humans.

But the EPA’s ban on TCE is in greater peril than the rest because it has yet to take effect. The prohibition on the chemical was to begin this year for all consumer uses and many industrial and commercial uses. The EPA allowed a more gradual phasing out for more than a dozen industrial uses, such as for some aerospace and defense applications. In those cases, the Biden EPA required employers to provide health protections for workers who come into contact with TCE. The Trump EPA’s recent petition to the federal appeals court to extend the ban’s delay would also mean that employers would not be required to implement the new health protections for workers.

Delaying the ban means that people will continue to be exposed to the chemical, which causes liver cancer, kidney cancer and non-Hodgkin lymphoma, as well as holes in infants’ hearts that can be fatal. While safer alternatives now exist for many of its uses, TCE has seeped into the drinking water of more than 17 million people in the U.S., according to data compiled by the nonprofit Environmental Working Group. Dangerous plumes of TCE have been identified in Woburn, Massachusetts; Wichita, Kansas; and Camp Lejeune Marine Corps base in North Carolina, where hundreds of service members developed Parkinson’s disease and cancer. There is another TCE plume on Long Island in New York, in the district abutting the one that EPA Administrator Lee Zeldin represented in Congress.

The idea that people will still be exposed to TCE infuriates Jerry Ensminger. This chemical “needs to go away,” said the retired Marine Corps master sergeant who’s an outspoken advocate for military families exposed to TCE. Ensminger’s daughter Janey died from leukemia when she was 9; Ensminger said Janey was conceived at Camp Lejeune and the family lived there during most of the pregnancy’s first trimester, then returned when she was 6. Ensminger recalled seeing workers on the base dip truck engines into vast metal vats of TCE in the late 1970s and early 1980s.

Scientists began raising concerns about the toxicity of TCE almost a century ago. The EPA’s work on the chemical proceeded slowly. In 1987, it deemed TCE a “probable human carcinogen.” In 2001, a draft EPA assessment found the chemical to be more toxic than previously thought and highly likely to cause cancer. The conclusion came under attack from some industry and government scientists. The Department of Defense, which is responsible for hundreds of TCE-contaminated sites, criticized the report as based on “junk science.” Two reviews by panels of independent scientists, however, found the assessment was sound. Still, the EPA didn’t begin drafting stricter regulations on TCE until the end of President Barack Obama’s administration.

Those efforts were dealt a blow during Trump’s first term when the EPA weakened a report on TCE’s effects on fetal heart abnormalities and stopped work on the new regulations. Nancy Beck, who before joining the first Trump administration had been a high-level lobbyist for the American Chemistry Council, an industry trade group, presided over the EPA’s chemical program when it pulled back from the TCE ban and, more broadly, retreated from rules that the chemical industry saw as burdensome.

After returning to the private sector, Beck was recently named the principal deputy assistant administrator in the EPA’s office of chemical safety and pollution prevention. She did not respond to requests for comment.

Her appointment has left environmentalists despairing over the fate of the long-awaited TCE ban.

“The same industry lobbyist who was in charge of EPA’s chemical program before is in charge of it again,” said Daniel Rosenberg, director of federal toxics policy at the Natural Resources Defense Council. “When she was there the first time, she moved heaven and earth to weaken the evaluation of the chemical and downplay the hazard TCE posed to people’s health. That appears to be where this is headed again.”

More than 100 groups representing public health, environment and community interests recently sent a letter to Zeldin urging him to reinstate the TCE ban. Referencing Zeldin’s proclaimed interest in clean water for every American, the letter noted that the EPA estimated its rule would produce $20 million in health benefits from reduced cancer rates and said that “delaying implementation of these rules will lead to preventable death, disease and incapacitation and increase medical costs and hardships to families and communities.” This week, environmental and labor groups filed a court brief opposing the EPA’s efforts to delay implementation of the TCE ban.

The EPA did not respond to questions about the TCE ban. Sen. John Kennedy, R-La., who introduced the resolution to repeal the TCE ban in the Senate, and Reps. Mariannette Miller-Meeks, R-Iowa, and Diana Harshbarger, R-Tenn., who introduced a resolution for its repeal in the House, also did not respond to inquiries from ProPublica. A spokesperson from the American Chemistry Council referred ProPublica to its press release from December, which acknowledged that the EPA had included “important adjustments” in the TCE ban to provide flexibility to affected industries.

In a press release about his bid to repeal the ban, Kennedy said that the “Biden administration waged war against America’s chemical producers,” and he urged Congress to “move quickly to take off the handcuffs that President Biden placed on Louisiana and U.S. businesses.” In the same release, Harshbarger described the TCE ban as “one of many examples of the Biden Administration’s overregulation.”

In a hearing about chemical regulation in the House in January, Harshbarger said that a company in her district, Microporous, which makes membranes used in lithium-ion batteries, is facing an “existential threat” from the TCE ban. The ban made an exception for the use of TCE for this purpose, allowing the battery industry to continue using it until 2044. Microporous, which has challenged the ban in court, did not respond to a question about why it needed 20 years to find a suitable replacement for TCE.

Since Trump’s inauguration, the EPA has been touting its efforts to roll back environmental protections. Earlier this month, the agency announced the “most consequential day of deregulation in U.S. history,” listing 31 rules it planned to step away from, related to oil and gas, air pollution and greenhouse gases. The agency celebrated the announcement with a 6,500-word press release that included praise from 61 industry leaders, CEOs and Republican politicians.

Still, some who have been focused on TCE were surprised that the Trump administration was delaying and reconsidering the recent ban. “I thought it was a done deal,” said Dr. Sara Whittingham, a retired United States Air Force flight surgeon who was diagnosed with Parkinson’s disease at 46. When she heard that the rule might be repealed, she was aghast. “What the heck, how can nobody care about this?” she said. “This should be a nonpartisan issue.”

Whittingham believes her disease may stem from the two years she spent as an aircraft maintenance officer at Kelly Air Force Base in San Antonio, Texas, from 1996 to 1998. Her office was above a shop where workers used TCE to clean engine parts.

Last week, Whittingham teamed up with two friends, both Air Force graduates who were diagnosed with Parkinson’s as women in their 40s, to urge people to pressure Congress to drop the resolutions.

“We signed up to go fight for our country,” she said, but now the attitude seems to be, “‘We don’t care about your health, you’ve already signed on the dotted line.’ It’s a kind of a kick in the face.”

Before being diagnosed with Parkinson’s, Whittingham had hoped that her children would follow her career path. But recently she discouraged her daughter, who is a senior in high school, from joining the military. The health risks, she said, were too high.