OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

October 25, 2012

MEMO TO FILE

SUBJECT: Conclusions Regarding the Pre-Biological Opinion Registration of Kaput-D

®

Prairie 

Dog Bait for Use on Black-Tailed Prairie Dogs

The purpose of this memorandum is to document EPA’s conclusion that the issuance of a timelimited new use registration for Kaput-D

®

Prairie Dog Bait (to control Black-tailed Prairie Dogs 

(BTPD); hereafter referred to as Kaput), prior to the completion of consultation with the U.S. 

Fish and Wildlife Service (FWS), is not likely to jeopardize the continued existence of any 

federally-listed endangered or threatened species, or result in the destruction or adverse 

modification of critical habitat of such species. This restricted use product is a bait that contains 

the active ingredient diphacinone, which must be applied by hand or mechanically on rangeland 

and adjacent non-crop areas at least 6” into active BTPD burrows. No bait is to be placed on or 

above ground level. The product label restricts use to the 10 states of CO, KS, NE, NM, ND, SD, 

WY, TX, MT and OK. 

Given the FWS April 9, 2012 “no jeopardy” Biological Opinion (BiOp) for Rozol Prairie Dog 

Bait (a similar anticoagulant rodenticide containing the active ingredient chlorphacinone; 

hereafter referred to as Rozol) (http://epa.gov/espp/2012/borozol-final.pdf) and the agreement of 

the applicant for Kaput to implement all of the conservation measures and Reasonable and 

Prudent Measures (RPMs) specified in the Rozol BiOp for Kaput, no impacts of concern are 

expected to occur for Kaput during the period when consultation is occurring for this new 

product. As described in the Environmental Fate and Effects Division’s Ecological Risk 

Assessment for the Section 3 new use registration of diphacinone on BTPDs (EPA, 2012), Kaput

has a similar exposure and ecotoxicity profile to Rozol, and the area of potential use for the two 

rodenticides is identical, given that they are both applied by the same method for use only on 

BTPDs during the same use season (October 1 to March 15) in the same 10 state area within the 

range of BTPDs. Therefore, the listed species that may be exposed to Kaput are also identical to 

those exposed to Rozol. Given that the exposure and toxicity profiles of Rozol and Kaput are 

similar, the conservation measures and RPMs identified for Rozol should also be protective of 

endangered species if implemented on the Kaput label. In addition, the labels for both Rozol and 

Kaput stipulate that other anticoagulant rodenticides cannot be used if applying either of these 

products; therefore, there is no potential for additive exposure. As such, the registration of Kaput 

is not expected to increase, change the route of, or otherwise significantly alter non-target 

organisms’ exposure to anticoagulant rodenticides. 
As an additional safeguard, the Kaput product will be registered on a time-limited basis, such 

that the registration will only authorize sale and distribution of the product for the 2012-2013 use 

season. The consultation process with FWS for Kaput began on October 25, 2012, concurrent 

with registration of the produce, and is currently expected to be completed prior to December 10, 

2012.

U.S. Environmental Protection Agency (EPA). 2012. Ecological Risk Assessment for the 

Section 3 New Use Registration of Diphacinone (PC 067701) For Use on Black-tailed 

Prairie Dogs (Cynomys ludovicianus). Office of Pesticide Programs. Environmental Fate 

and Effects Division. June 28, 2012.