The Army Corps of Engineers, which runs the Washington Aqueduct facility, annually dumps some 200,000 tonnes of "sludge" - sediments produced from making river water drinkable - into the National Heritage river under an Environmental Protection Agency permit.

EPA and Army Corps officials say studies have not proven that the sediment, despite its smell and appearance, harms the fish, which was previously thought to be extinct in the area.

But Western lawmakers, who say the EPA would never tolerate in their districts such discharges even potentially harmful to an endangered species, accused federal agencies in the capital of turning a blind eye closer to home as a matter of routine.

"We have long suspected that if laws, such as the Endangered Species Act, were enforced the way they are in the rural West, that the urban parts of the country would simply not stand for it," House of Representatives Resources Committee Chairman James Hansen, a Utah Republican, told EPA and Army Corps officials at a hearing.

POTENTIALLY HARMFUL

Officials agree that conditions in the area where the sediments are dumped into the river ordinarily would correspond to those favored by the sturgeon for breeding, if not for the discharge forming a foul-smelling black plume across the waterway.

They also agree that the sludge is potentially harmful to the sturgeon's eggs, and a draft renewal permit for the Army Corps would ban any discharges during the sturgeon's spring spawning season.

But the EPA says it remains unclear whether there actually are any sturgeon present in the part of the Potomac that runs through Washington, let alone whether they breed in the area.

Questioning the EPA's scientific analysis of the problem, California Republican Rep. George Radanovich wondered why the agency did not just ban the discharge altogether and order construction of a new facility to treat the sludge for transportation to a landfill.

"If something like this was done in Yellowstone River or Yellowstone National Park would it fly?" added Nebraska Republican Thomas Osborne after watching a video showing a sludge-slicked beaver paddling in contaminated water and trying to shake the goo's synthetic foam from its muzzle.

Lawmakers cited as an example of the human and economic cost of strict enforcement of environmental laws in the West a fight in Oregon last year between federal agents trying to preserve scarce water for endangered sucker fish and farmers desperate to save their crops during a drought.