Several hundred houseboat batteries were discarded into Lake Powell over the past seven years and private boat-owners were improperly renting their crafts, costing the government an estimated $400,000 yearly in lost fees, an Interior Department audit says.

In December, a Deseret News article about the dumped batteries quoted a National Park Service official as saying the service was prepared to close Glen Canyon Recreation Area if the pollution was dangerous but that it turned out not to be. Batteries pose an environmental hazard because acid and lead contamination can seep into the water.In the latest development, the audit by the department's Inspector General in Washington, D.C., cites below-standard practices at Lake Powell. The March 19 report and the National Park Service's Jan. 31 response to some specific allegations were obtained from the Park Service.

Also, many of the estimated 4,000 private boat owners used Park Service boat pump-out facilities without having permits or paying fees, says the report, sent to the secretary of the Interior Department by Inspector General James R. Richards.

"The Park Service generally concurred with the report's recommendations which, if implemented, should improve controls over houseboat activities and increase recreational fee revenues," Richards wrote. The NPS proposed to increase recreational fee revenues by about $7 million over the first five years of the new scheme, and the inspector general accepted the recommendation.

Lake Powell is within Glen Canyon National Recreation Area, which stretches along the border of Utah and Nevada. The recreation area is managed by the Park Service.

A memorandum by Harold Bloom, assistant inspector general for audits, says auditors believe batteries, boating equipment and chemicals were improperly disposed of in Lake Powell, including dissolved paint, grease and oil.

"As a result, sections of Lake Powell may be polluted and pose potential health hazards to both humans and wildlife."

The report cites a failure by the Park Service to properly monitor activities on the lake.

Park Service spokesman George Berklacy told the Deseret News that as far as unsafe conditions at Lake Powell are concerned, "We categorically deny that."

Arizona public health experts tested Lake Powell, "and they have advised us that the lake is safe and no sections need to be closed."

Meanwhile, he said, the Arizona attorney general's office has been investigating, as battery-dumping may violate the Clean Water Act of 1977.

Bloom wrote that the Park Service was not issuing special recreation permits to boat owners who used Park Service pump-out facilities, allowing them to empty boat toilets for free.

ARA Leisure Services, based in Philadelphia - the concessioner for marinas at the lake - charges $10 per boat for pump-out service at Bullfrog and Hall's Crossing marinas.

"Additionally, privately owned houseboats were operating improperly as commercial entities on Lake Powell because of limited control over private boating activities.

"As a result, the Park Service is losing an estimated $400,000 in recreational fees annually," he wrote.