OBILE, Ala., April 4 — The Food and Drug Administration has begun using the Environmental Protection Agency's much lower safe level for mercury in the human body, an official of the food and drug agency said this week.

Before the change, the F.D.A. guidelines set a safe level that was four times as high as that of the environmental agency's standard.

"The F.D.A. is basing its advisory on the E.P.A.'s reference dose," Dr. David Acheson, the newly appointed chief medical officer in the F.D.A.'s science office, said in an interview first reported in The Mobile Register. "Are we formally endorsing it? I'm not aware, but we are certainly using it and pay attention to it."

A paper in the current issue of The Journal of the American Medical Association detailed the new position.

"This is really a landmark paper," said Kathryn R. Mahaffey, an E.P.A official who helped write the article. "It's really a consensus on what we know about mercury."

Dr. Acheson said the food and drug agency planned to add more fish to its list of those that should not be eaten if new mercury testing reveals that a species tends to exceed the new levels.