An aggressive push by Congress to pass bipartisan legislation addressing cancer-causing chemicals that are leaching into the water supply is setting the stage for a fight with the Trump administration. The chemicals, commonly abbreviated as PFAS, are used in items ranging from food wrappers and Teflon pans to raincoats and firefighting foam. But studies have found that as they break down and find their way into drinking water, they can cause a variety of negative health effects. PFAS has been linked with kidney and thyroid cancer along with high cholesterol and other illnesses. Contamination has spread to 43 states, and a 2015 study found 98 percent of Americans tested now have the chemical in their blood.