The Environmental Protection Agency has turned aside -- at least temporarily -- a request to cancel the registration of the blood-thinning poison Rozol.

In a decision made public Wednesday, the EPA announced that it didn't think "immediate initiation of cancellation or suspension proceedings of Rozol Prairie Dog Bait is warranted."

However, the letter to the World Wildlife Fund, which requested the suspension, said the EPA has initiated formal consultation with the U.S. Fish and Wildlife Service concerning the poison's effect on endangered species, such as the black-footed ferret.

The registration review process was first initiated in October 2009, after the WWF filed its complaint with the EPA. The review came two weeks after Defenders of Wildlife and Audubon of Kansas filed a federal lawsuit against EPA for its registration of Rozol.

The lawsuit also took aim at EPA's consideration of registration request for Kaput-D, a product that contains diphacinone, another blood-thinning chemical.

That lawsuit remains alive, and Defenders earlier this month filed a motion for summary judgment in the case.

That motion asks the court to set aside the EPA's decision.

Vacating the decision "is needed to protect the environment and to wipe clean, as much as possible, the tainted administrative slate," the filing states. "Any EPA consideration of future chlorophacinone use should be made only if lawfully informed by other agencies and the public as a whole. Any future registration must reflect not after-the-fact rationalization of the status quo but rather a fresh decision, made from start to finish with the burden on the registration proponent and memorialized in a careful and formal justification, responsive to both statutory direction and information garnered from beyond the applicant and EPA itself. In the meantime, threats from EPA's illegal and ill-considered registration should be abated."

The lawsuit was filed in September 2009, citing a request from the federal wildlife agency for the consultation.

"We recommend that EPA withdraw the registration for Rozol and not issue a registration for prairie dog control for Kaput until EPA completes a formal consultation with the (Fish and Wildlife) service on the use of rodenticides to control black-tailed prairie dogs," a letter from FWS states.

The EPA's decision was made public Wednesday when the agency released its letter to to WWF, along with a number of other documents.

In justifying its decision not to cancel registration of Rozol, the EPA cited several steps that have been taken, including working with FWS on concerns involving endangered species, especially the black-footed ferret.

EPA also cited revisions in requirements for carcass searches, disposal and use of Rozol from Oct. 1 through March 15.

The other documents released Wednesday include brief accounts of meetings the EPA had with several organizations, including the Humane Society of the United States, the Kansas Farm Bureau and American Farm Bureau.

The EPA also made a site visit to Bismarck, N.D., to "meet with representatives from the North Dakota Department of Agriculture to observe black-tailed prairie dog behavior and their agricultural impact."