The Environmental Protection Agency has issued the first national guidelines establishing safe levels for perfluorinated chemicals used to make nonstick and stain-resistant materials in the nation’s drinking water.

The chemical, which has been linked to cancer and birth defects in animals, is a key processing agent used to make products including microwave popcorn bags and nonstick pans. It has been seeping into drinking water supplies around the country and has been detected in the blood of 95 percent of Americans, including pregnant women, as well as in the blood of marine organisms and Arctic polar bears.

Environmentalists criticized the “provisional health advisory” setting the acceptable level of short-term exposure to perfluorooctanoic acid (PFOA) at 0.4 parts per billion. They noted that Lisa P. Jackson, who headed New Jersey’s Department of Environmental Protection and has been nominated by President-elect Barack Obama to take over the EPA, set a chronic exposure standard of 0.04 ppb in 2007 while heading the state agency.

Benjamin H. Grumbles, the EPA’s assistant administrator for water, said in an interview that the agency decided to issue guidelines Thursday after it had found elevated levels of both PFOA and perfluorooctane sulfonate (PFOS) in sewage sludge from a wastewater treatment plant that was used to fertilize farm crops near Decatur, Ala. The agency set a standard of 0.2 ppb for PFOS.

“We have no evidence of levels that would present a risk to public health,” Grumbles said of the drinking water near Decatur, adding that the agency defines “short-term exposure” as lasting as much as two years. He said the suggested safety levels apply nationwide but could be revised by the next administration.

“I’ve no doubt scientists in the agency will continue to look at this, and policymakers may revisit it,” Grumbles said, adding that although the EPA’s recommendation differs from New Jersey’s, “we feel that’s the best available science, and that’s the right number to select.”

Richard Wiles, executive director of the Environmental Working Group, said the EPA failed to take into account that drinking water exposure to PFOA produces a hundredfold concentration of the chemical in human’s blood.

“Nobody would say that’s safe,” Wiles said of a 40 ppb concentration. “It’s a pretty big win for the polluters.”

Chemical giant DuPont issued a statement saying the new advisory is in line with other exposure guidelines. Parkersburg, W.Va., which is near a DuPont plant that produces the chemical, has set a local safety limit of 0.5 ppb, which is identical to the level established by the Minnesota Department of Heath.

“We are reviewing the document, and at this time it appears the advisory value for PFOA is consistent with nearly all regulatory guidelines established by EPA regions, states and other countries,” the DuPont statement said.

Eight U.S. companies, including DuPont, have agreed that by 2015, they will no longer release PFOA into the environment from finished products or manufacturing plants, and that they will cut emissions of the chemical 95 percent by next year.