Rep. John Salazar, D-Colo., called DeFazio's fears overstated.

A farmer and cattle rancher, Salazar said both pesticides are safe, "environmentally sound tools registered by the Environmental Protection Agency and used only by trained and certified applicators."

Use of the pesticides "is highly target-specific, in limited applications, and in compliance with the regulations of the EPA and local jurisdictions," Salazar wrote in a letter urging colleagues to defeat DeFazio's bill.

Without effective tools to protect them from predators, livestock losses from coyotes and other wildlife could be two to three times higher than current levels — estimated at $16.3 million per year in the sheep industry and $51 million in cattle losses, according to the Colorado Wool Growers Association, which represents the state's 1,600 sheep farms and ranches.

"Regardless of the size of operation, each sheep farm or ranch needs protection against predators, and many operations rely on the assistance and expertise" provided by the Wildlife Services agency, the group said in a letter opposing the ban.

Salazar encouraged colleagues to "stand up for the thousands of livestock producers in our country who provide the world's most abundant food supply and oppose this legislation."

DeFazio said it's unfortunate that the bill's leading opponent is a fellow Democrat and Westerner but said he would push forward with the measure, the latest in a years-long effort to ban the two poisons.

The bill comes as the EPA has taken a long-delayed step toward banning use of the poisons on federal lands. The agency has set a March 5 deadline for public comments on a proposal drafted in response to a petition from a coalition of environmental groups.

The EPA has not reached a decision on the petition and is conducting its own analysis to determine if the pesticides "pose unreasonable adverse effects on the environment," said Dale Kemery, an agency spokesman.

Compound 1080 is made primarily by Alabama-based Tull Chemical Co., while M-44 capsules are produced by the Agriculture Department's Pocatello Supply Depot in Idaho. Warning signs in English and Spanish are required near locations where the poisons are used.

On the Net:

The bill is H.R. 4775. Congress: thomas.loc.gov/

Agriculture Department Wildlife Services Program: www.aphis.usda.gov/wildlife—damage/

Predator Defense: www.predatordefense.org