BALTIMORE (AP) — The polluted waters of the Chesapeake Bay are harboring bacteria that's posing an increasing health risk to humans, a bay watchdog group warned today in a report that criticizes federal environmental regulators.

The Chesapeake Bay Foundation noted increases in Virginia and Maryland of the number of infections from the saltwater bacteria known as Vibrio, some varieties of which can cause life-threatening skin and blood infections and intestinal illnesses.

The report faulted the Environmental Protection Agency for failing to clean up the bay as required under the federal Clean Water Act.

"The thought that you can't swim in the Chesapeake Bay because you may contract a disease or a bacterial infection, that's outrageous, especially if the laws aren't being enforced," foundation president William C. Baker said.

President Barack Obama called the Chesapeake "a national treasure" in a May executive order that put the federal government in charge of cleanup efforts that previously were led by states.

Jeffrey Lape, director of the EPA's Chesapeake Bay Program, did not dispute that the agency has fallen short of its cleanup goals.

"We're on clear record of acknowledging that much more needs to be done to restore the bay," Lape said. "I think we're trending in the right direction. We just still have some challenges to address."

Health officials in Virginia reported 30 infections from Vibrio bacteria last year, up from 12 in 1999, the report said. Reported cases also rose in Maryland, but a change in reporting requirements may have contributed to the increase.

Rising water temperatures and nutrient pollution are fueling algae blooms that allow bacteria to thrive in the bay, according to scientists quoted in the report.