UPTON, N.Y. — As a technician at Brookhaven National Laboratory, one of the nation’s most prestigious science labs, Joseph Marino’s job in the late 1990s and early 2000s was to clean and maintain the supercomputers that have helped researchers unlock some of the world’s biggest scientific and medical mysteries. He polished copper connectors, he said, until “they reminded you of gold. ”

One of the cleaning fluids he used while wiping the machines by hand over the years was trichloroethylene, or TCE, a toxic degreaser that the Trump administration has targeted as part of its broad effort to weaken regulations on chemicals . TCE is still widely used by dry cleaners as a stain remover and by factories as a degreaser .

Mr. Marino, who later lost a kidney to cancer, is now suing the operators of the Department of Energy lab for $25 million over exposure to TCE, alleging that they negligently supplied the cleaner to him and many other workers there without warnings or protections. He is also suing Dow Chemical and Zep, alleging that they made and sold the chemical without adequate safety warnings.

The lawsuit is a rarity. Most TCE claims are settled through a limited workers’ compensation system that, in Mr. Marino’s case, awarded him $50,000 for his exposure to the chemical, plus $15,000 a year for lost wages — sums he says barely cover his health care. So, Mr. Marino chose to take on the operators of the lab directly, opening up a significant new battle front.