Document ID: EPA-HQ-OPP-2006-0955-0002
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-01-17T05:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

							                                              OFFICE OF

				PREVENTION, PESTICIDES

	AND TOXIC SUBSTANCES

	

Proposed Risk Mitigation Decision for Nine Rodenticides

January 17, 2007

I.	Proposed Decision and Comment Opportunity

This document describes the Environmental Protection Agency’s
(EPA’s) proposed risk mitigation decision for rodenticide bait
products containing the following nine active ingredients: brodifacoum,
bromadiolone, difethialone, chlorophacinone, diphacinone, warfarin, zinc
phosphide, bromethalin, and cholecalciferol.  

Based on an evaluation of the ecological risks associated with the use
of rodenticide bait products containing these nine active ingredients,
and consideration of the public health and other important benefits of
the use of rodenticides, EPA anticipates classifying all bait products
containing the active ingredients brodifacoum, bromadiolone, and
difethialone as restricted use pesticides.  To decrease the possibility
of children’s exposure to rodenticide products used in homes, EPA also
anticipates requiring that all rodenticide bait products available for
sale to consumers be sold only in tamper-resistant bait stations with
solid bait blocks as the only permissible bait form.  Finally, EPA is
proposing labeling improvements to mitigate the risks associated with
bait products containing any of these nine rodenticides.

The proposed risk mitigation decision would decrease the possibility of
unreasonable adverse effects to wildlife and children from the use of
rodenticides, but would allow residential and professional users access
to a wide variety of effective and appropriate rodenticide products. 
The Agency anticipates that the requirement for tamper-resistant bait
stations may result in a modest price increase for rodenticide products
sold on the consumer market, but has concluded that the benefits from a
reduction in children’s exposure to rodenticide bait products
outweighs the estimated cost increase.  EPA believes that with the
proposed mitigation measures in place, rodenticide products will remain
affordable for economically-disadvantaged populations, and also notes
that there are other effective and affordable methods of rodent control,
such as spring traps and glue boards, in addition to rodenticide
products.

The purpose of this document is to outline the Agency’s rationale for
these proposed decisions and solicit comment.  Comments are specifically
requested on the Agency’s proposed risk mitigation decisions and
impact assessment, and the mitigation proposals put forth by various
stakeholders.  Supporting documents can be found at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  under docket number
EPA-HQ-OPP-2006-0955 (recent documents) or EPA-HQ-OPP-2004-0033 /
EPA-HQ-OPP-2002-0049 (older documents and previous public comments). 
Public comments will be accepted for 60-days following publication of a
Federal Register Notice of Availability on January 17, 2007.  During the
comment period, EPA will continue its ongoing consultation with the
Centers for Disease Control and Prevention (CDC), the U.S. Department of
Agriculture (USDA), the U.S. Fish and Wildlife Service (FWS), and the
Department of Housing and Urban Development (HUD).  After the close of
the comment period, the Agency will review and consider all comments
received and issue its final decision.  

II.	Ecological Risk Concerns and Proposed Mitigation

	For more information about ecological risk concerns, please see EPA’s
“Comparative Ecological Risk Assessment for Nine Rodenticides”
(Erickson and Urban, 7/04), located in docket number
EPA-HQ-OPP-2006-0955 at   HYPERLINK "http://www.regulations.gov" 
www.regulations.gov .

Background

In connection with the Federal Insecticide, Fungicide and Rodenticide
Act (FIFRA) section 4 reregistration requirements, EPA issued
Reregistration Eligibility Decisions (REDs) for the Rodenticide Cluster
and Zinc Phosphide in 1998.  Following the issuance of those REDs, EPA
developed a Comparative Ecological Risk Assessment for Nine Rodenticides
to further evaluate the potential for rodenticide bait products to pose
ecological risks to non-target birds and mammals.  The nine rodenticides
included in the Comparative Ecological Assessment are brodifacoum,
bromadiolone, difethialone, warfarin, chlorophacinone, diphacinone,
bromethalin, cholecalciferol and zinc phosphide.

The nine rodenticide active ingredients can be divided into three
categories: first-generation anticoagulants, which are warfarin,
chlorophacinone, diphacinone; second-generation anticoagulants, which
are brodifacoum, bromadiolone, and difethialone; and non-anticoagulants,
which are bromethalin, cholecalciferol and zinc phosphide.  The
anticoagulants interfere with blood clotting and death results from
hemorrhage, bromethalin is a nerve toxicant that causes respiratory
distress, cholecalciferol causes hypercalcemia (excessive calcium) in
the blood and other body tissues, and zinc phosphide causes liberation
of phosphine gas in the stomach.  

All nine rodenticides are used in bait products to control rats and mice
in and around buildings.  Chlorophacinone, diphacinone, and zinc
phosphide also have field uses (e.g. in orchards and rangelands). 
Brodifacoum and diphacinone have island conservation uses that are
managed by the FWS. 

EPA’s comparative ecological risk assessment concludes that all nine
rodenticide active ingredients pose significant risks to non-target
wildlife when applied as grain-based bait products.  The risks to
wildlife are from primary exposure (direct consumption of rodenticide
bait) for all compounds and secondary exposure (consumption of prey by
predators or scavengers with rodenticide stored in body tissues) from
the anticoagulants.  Secondary exposure to the second-generation
anticoagulants is particularly problematic due to the compounds’ high
toxicity and long persistence in body tissues (liver retention
half-lives of greater than 300 days).  The second-generation
anticoagulants are designed to be toxic in “a single feeding,” but
since time-to-death is several days, the target rodent can feed multiple
times before death, leading to a carcass containing residues that may be
many times the lethal dose.  Additionally, the extended persistence in
the body of second-generation anticoagulants can result in additive
adverse effects from multiple feedings that are separated by days to
weeks.  

		EPA’s comparative ecological risk assessment followed multiple lines
of evidence and concluded that the second-generation anticoagulants have
greater potential to adversely affect non-target wildlife, especially
birds, than the first-generation anticoagulants.  These lines of
evidence include acute toxicity, persistence of compounds in body
tissues of primary consumers (i.e., bait eaters), information from
laboratory and pen studies in which poisoned prey are fed to predators
or scavengers in various amounts for one or more days, data from field
trials and operational control programs, and wildlife mortality
incidents.  In some wildlife mortality incident reports, the
relationship between rodenticide exposure and incident outcome is not
established, although in many cases the examining toxicologist concluded
that a rodenticide likely caused or contributed to the mortality.  

		Anticoagulants typically do not cause death until 4 to 10 days or more
after a lethal dose is ingested.  However, exposed individuals become
progressively weaker and lethargic due to blood loss, which may
contribute to the animal’s death, even where the proximate cause of
death may be identified as predation, disease, or automobile collision. 
Even if a cause-effect relationship with rodenticides has not been
determined for many wildlife mortality incidents, the detection of
rodenticides in a wide variety of non-target wildlife, both birds and
mammals, confirms that exposure to the compounds has occurred.  As
discussed in EPA’s updated ecological incident report, several
monitoring programs have found that major portions of some non-target
animal populations are being exposed to second-generation anticoagulant
rodenticides.  The updated ecological incident report, “Rodenticide
Incidents Update” (Erickson, 11/15/06), may be obtained at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  under docket number
EPA-HQ-OPP-2006-0955.

Incident reports have identified many taxa of non-target animals exposed
to rodenticides, including strict carnivores such as mountain lions,
bobcats, hawks and owls; omnivores such as coyotes, foxes, skunks and
raccoons; and granivores and herbivores such as squirrels and deer. 
EPA’s updated rodenticide ecological incident report documents
anticoagulant residues in 27 avian species and 17 mammalian species. 
For some species (e.g. bobcats, foxes, great horned owls), carcasses
frequently contain residue of two or more anticoagulants, usually second
generation compounds.  In approximately 50% of those incidents, necropsy
results indicate that it is highly probable that a second-generation
anticoagulant was the cause of the death.  

In the United States, only New York (NY State Department of
Environmental Conservation) has been actively tracking wildlife
mortality incidents associated with anticoagulants, but funding limits
analysis and reporting (many dead raptors still await necropsy and
residue analysis).  California (Department of Fish and Game) also has
reported numerous incidents, but currently has no monitoring program. 
Analyses for anticoagulants are expensive and funding availability
limits wildlife mortality incident reporting.  There is no reason to
believe that wildlife mortality incidents associated with
second-generation anticoagulants are exclusive to these two states. 
Therefore, EPA believes that widespread exposures to second-generation
anticoagulants are occurring wherever rodenticides are being used. 
Moreover, residue analyses indicate that exposure is widespread in
non-target populations.  In New York, second-generation anticoagulants
were detected in 48% of 265 (15 species) diurnal raptors and owls
analyzed, including 81% of 53 great horned owls, 58% of 78 red-tailed
hawks, and 45% of 22 Eastern screech-owls.  In California,
second-generation anticoagulants were detected in 71% to 84% of the 106
bobcats, mountain lions, and San Joaquin kit foxes analyzed.

Additionally, second-generation anticoagulants have been identified as
an environmental issue in many countries, with Canada, the United
Kingdom, France, New Zealand, and the United States focusing on incident
monitoring and research results.  A recent one-day scientific meeting
was held in Montreal, following the November 2006 annual meeting of the
Society of Environmental Toxicology and Chemistry (SETAC), to discuss
the environmental impacts of the second-generation anticoagulants.  

EPA’s Risk Mitigation Proposal to Decrease Risks to Wildlife

Based on an evaluation of the ecological risks associated with the use
of bait products containing any of the nine rodenticide active
ingredients, and consideration of the public health and other important
benefits of the use of rodenticide baits, EPA is proposing to classify
all bait products containing the active ingredients brodifacoum,
bromadiolone, and difethialone as restricted use pesticides pursuant to
FIFRA section 3(d).   Classifying bait products containing these
second-generation anticoagulants as restricted use pesticides would
limit their use to certified applicators who have had sufficient
training to know when to use the products and how to use them in order
to limit risks.  This risk mitigation measure would preserve the
availability of the second-generation anticoagulants to meet critical
public health needs in specific situations, but would result in marked
overall reduction in exposure to and adverse effects from those
compounds.

In addition, EPA is proposing to require that all outdoor, above-ground
placements of bait products containing second-generation anticoagulants
be contained in tamper-resistant bait stations, to deny non-target
animals ready access to rodenticide bait.  Most baits are grain-based
and are therefore attractive to many birds and non-target mammals; those
baits with flavor enhancers (e.g. fish flavors) might also attract
carnivores.  Currently, most rodenticide product labels require that
rodenticide baits which are placed outdoors and above ground be
contained in a tamper-resistant bait station if the bait placement would
be within reach of pets, domestic animals, non-target wildlife, or
children under six years-of-age.  According to the wildlife mortality
incident reports, non-target herbivorous wildlife such as deer and
squirrels are in fact being exposed, presumably from unprotected or
inadequately protected outdoor above-ground placements of unprotected
bait.  If these animals are in turn consumed by predators or scavengers
prior to elimination of rodenticide residues, additional animals would
be exposed beyond those exposed from eating the target species. 
Therefore, the requirement of a tamper-resistant bait station is
expected to reduce overall non-target wildlife exposures and resulting
adverse effects. 

Why “Indoor Use Only” Would Not Be Sufficiently Effective at
Mitigating Risks to Wildlife

EPA is not proposing to limit use of baits containing the
second-generation anticoagulants to indoor use even though such a
limitation has been suggested by some groups as an alternative
mitigation measure to minimize risk to wildlife.  EPA has concluded that
it is important to allow the use of second-generation anticoagulants in
outdoor areas by certified applicators.  There are certain public health
and sanitation situations such as urban alleys and trash collection
areas with many rodent food sources where compounds that can kill as the
result of a single feeding are useful for adequate rodent control. 
Additionally, outdoor use is important in perimeter control in
agricultural and food warehouse settings, and in certain wildlife
recovery programs where rodent eradication is crucial.  An
indoor-use-only restriction would preclude adequate control in these
situations.   

Additionally, an indoor-use-only limitation would reduce primary
exposures to non-target animals, but would not decrease secondary
exposures.  Because rodents move in and out of indoor spaces, a rodent
exposed to a rodenticide bait indoors may be preyed upon or die
outdoors, which may result in secondary exposures.  Since EPA has, for
many years, registered rodenticides for use “in and around” human
structures, residential users may not consistently comply with an
indoor-use only limitation.  Since rodents do come in from the outdoors,
baiting around the home, garage, patio, woodpile, and other similar
outdoor areas is often an effective way to target unwanted rodents. 
However, baiting “around” structures may result in primary as well
as secondary exposures since many non-target animals such as small
seed-eating birds, opossums, raccoons, skunks, and deer frequently occur
around buildings.  By making bait products containing second-generation
anticoagulants restricted use pesticides, only certified applicators
would be allowed to make outdoor bait placements, which would decrease
the likelihood of misapplication.  EPA’s proposed risk mitigation
would still allow residential users to bait “in and around” their
structures with rodenticide products containing active ingredients that
are less likely to harm non-target wildlife, and, pursuant to another
mitigation measure discussed below, in tamper-resistant bait stations.  

Sublethal Effects

There is ongoing research into the effects of sublethal doses of
anticoagulants on non-target wildlife and the consequences of the highly
persistent second-generation anticoagulants to bioaccumulate from repeat
exposures to one or more compounds.  Whether single or repeat sublethal
exposures cause adverse effects, such as impacts on reproduction or
behavior, are questions which are yet to be answered.  As EPA’s
proposed mitigation measures are targeted at reducing non-target
wildlife exposures to rodenticides, they are expected to reduce the
extent and severity of any sublethal effects in non-target wildlife. 

Endangered Species

	Several reported incidents have involved endangered species, including
San Joaquin kit foxes, Northern spotted owls, and bald eagles.  

	California incident records contain evidence of exposure and mortality
of endangered kit foxes in California.  Anticoagulant residues were
detected in 27 of 32 kit fox carcasses, and many showed signs of
extensive hemorrhage upon necropsy.  Brodifacoum was detected in all 27
carcasses, and several had residues of two or more anticoagulants.

The FWS issued a biological opinion on eight of the rodenticides in
1993.  The opinion does not include difethialone, which was first
registered in 1995.  The jeopardy determinations for the individual
compounds primarily recommend prohibiting use in habitat occupied by
listed species and requiring tamper-resistant bait stations for outdoor
placements for some uses.  The jeopardy determinations can be found in
EPA’s “Comparative Ecological Risk Assessment for Nine
Rodenticides” (Erickson and Urban, 7/2004), available under docket
number EPA-HQ-OPP-2006-0955 at www.regulations.gov.

In 2005, EPA and FWS entered an informal consultation phase for all nine
rodenticides.  Since rodenticide use is widespread and secondary
exposure issues with these compounds are complex and include migratory
species, the Federally-defined action area may be extensive.  EPA and
FWS will be working together to determine an appropriate plan of action
for the rodenticides.  Meanwhile, the mitigation measures proposed in
this document should have the beneficial effect of reducing non-target
wildlife exposures to rodenticides, and thus limiting the scope of the
endangered species risk assessment work, particularly for the
second-generation anticoagulants. 

III.		Children’s Exposure and Proposed Mitigation

Background	

	EPA issued REDs for the Rodenticide Cluster and Zinc Phosphide in 1998.
 In those REDs, the Agency expressed concern about reported exposures of
children to rodenticides.  The REDs articulated the Agency’s
determination that rodenticide bait products (other than those used
exclusively at agricultural sites) were eligible for reregistration only
if certain measures were adopted to reduce risks of harm to children. 
Among these mitigation measures, EPA specified two interim measures:
changing product formulations to incorporate a bittering agent and an
indicator dye.  The bittering agents were expected to make the baits
less palatable to children, and the indicator dyes were expected to show
whether a child had come into contact with a rodenticide product by
leaving a stain on a child’s mouth or hands.  These interim measures
were intended to reduce risks while new technologies for preventing
exposure were assessed by a stakeholder group.

In 1999, EPA formed the Rodenticide Stakeholders Workgroup (RSW) as a

subcommittee under the federally-chartered advisory body, the Pesticide
Program Dialogue Committee (PPDC), to consider the risks to children of
accidental rodenticide exposure and potential measures to reduce such
exposures.  The RSW membership was drawn from a broad range of
stakeholders and government representatives, including EPA, CDC, USDA,
the medical community, the rodenticide industry, public interest groups,
and members of the general public.  The RSW met five times in 1999, and
ultimately issued a report recommending that EPA drop the indicator dye
requirement due to the lack of suitable dye, and drop the bittering
agent requirement due to its potential adverse effect on the efficacy of
rodenticide baits.  The report recommended that EPA allow manufacturers
to include the bittering agents on a voluntary basis.  The Agency
adopted the RSW’s recommendations, and in November 2001, EPA issued a
Federal Register notice announcing that it was amending the two
rodenticide REDs to allow reregistration of rodenticide bait products
without requiring the incorporation of a bittering agent and indicator
dye.  

Since 2001, many rodenticide registrants have voluntarily incorporated a
bittering agent into rodenticide products.  The Agency maintains,
however, that there are some situations involving severe pest pressure
and/or substantial competing food sources when products without a
bittering agent may be required.  EPA’s decision not to require
inclusion of bittering agents in all rodenticides provides flexibility
for such situations.    

In November 2004, West Harlem Environmental Action and the Natural
Resources Defense Council filed suit in the District Court for the
Southern District of New York, challenging EPA’s 2001 reversal of its
1998 determination that rodenticide bait products posed an unreasonable
risk of harm to children unless they contained a bittering agent and an
indicator dye.  In August 2005, the District Court upheld EPA’s 2001
determination that an indicator dye should not be required.  But the
court reversed EPA’s decision to rescind the bittering agent
requirement, and remanded the decision to EPA “for further
consideration consistent with this opinion.” 

The court’s decision in 2005 has given focus to the Agency’s ongoing
efforts to determine how best to reduce exposure and risks to children
from rodenticide products.  EPA has observed that since 1993, the
American Association of Poison Control Centers (AAPCC) has reported
approximately 12,000 to 15,000 annual rodenticide exposures to children
6 years old or younger.  The AAPCC data fortunately shows that only a
small number of exposed children experience medical symptoms or suffer
adverse health effects as a result of their exposure.  Nonetheless, the
Agency believes that the number of exposure incidents is unacceptably
high because of the social costs associated with treating children who
might have been exposed, and the emotional toll of suspected exposure
incidents.  For more information about human incident data, please refer
to the following EPA documents, available at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  under docket number
EPA-HQ-OPP-2006-0955: “Updated Review of Poison Control Center Data
for Residential Exposures to Rodenticides” (Blondell, 3/22/99);
“Updated Review of Rodenticide Incident Reports Primarily Concerning
Children” (Blondell, 6/3/99); and “Updated Review of Rodenticide
Incident Reports Primarily Concerning Children” (Hawkins and Allender,
1/09/07).

EPA is concerned about children’s exposures to rodenticides, and
believes that a bittering agent is an inadequate means to address the
problem because the substance can only be tasted after the bait already
is in a child’s mouth.  The frequency of children’s exposure to
rodenticides has remained relatively constant over recent years, despite
the fact that the percentage of rodenticide bait products on the market
containing bittering agents has increased substantially.  This result is
not surprising given that bittering agents do not prevent the initial
exposure, but at most would decrease the amount of rodenticide bait a
child would consume by rendering the bait less palatable.

EPA’s Risk Mitigation Proposal to Decrease Children’s Exposure to
Rodenticides

EPA believes that the large number of children exposed to rodenticide
bait products is too high, and that more stringent requirements are
needed.  Rodenticide product labels currently direct users to apply
rodenticide bait products in locations inaccessible to children, and if
that is not possible, to place bait in a tamper-resistant bait station. 
However, the high number of children exposed to rodenticide bait
products indicates that these label instructions are not sufficiently
effective in keeping rodenticide bait products inaccessible to children.
 Because a large portion of the rodenticide baits used in the home
environment are consumer products applied by residential users, EPA
believes that a major cause of the child exposure incidents is
residential users’ failure to adequately comply with label directions
to apply rodenticide bait products in locations inaccessible to children
or in  tamper-resistant bait stations.  

For this reason, the Agency is proposing a requirement that any
rodenticide bait product available for sale to a consumer must be sold
in a tamper-resistant bait station, with solid bait blocks as the only
permissible bait.  Under this proposal, tamper-resistant bait stations
would be sold pre-loaded with bait blocks, and could be packaged for
sale with additional bait block refills.  Solid bait blocks would be the
only form of rodenticide bait approved for use in tamper-resistant bait
stations for the consumer market.  Pellets, grain baits, seed baits, and
other types of loose rodenticide bait products would not be permissible
for consumer products because of the potential for loose bait to be
scattered or shaken from a bait station, and the potential for a rodent
to move the bait outside of the bait station.

In 1994, EPA articulated the performance features required for indoor
and outdoor bait stations to be considered to be “tamper-resistant.”
 The following eight criteria for tamper-resistant bait stations were
set forth in Pesticide Registration (PR) Notice 94-7:  

Resistant to destruction or weakening by elements of typical
non-catastrophic weather (e.g., snow, rain, extremes of temperature and
humidity, direct sunshine, etc.);

Strong enough to prohibit entry or destruction by dogs and by children
under six years of age using their hands, their feet, or objects
commonly found in the use environment (e.g., sticks, stones, broken
glass, etc. – stations stronger than “tamper-resistant” are needed
in areas frequented by hoofed livestock, raccoons, bears, other
potentially destructive animals, or in areas prone to vandalism); 

Capable of being locked or sealed so that children and non-target
animals cannot gain access through the opening or procedures used to
fill the bait compartment(s);

Equipped with rodent entrances which a) readily allow target animals
access to baits, b) deny such access to other animals larger than adults
of the target species, and c) discourage entry by birds.  Means for
achieving these ends might include use of baffles, mazes, or small
entrances;

Capable of being anchored securely to resist efforts to move the station
or to displace its contents, or equipped with a mechanism which
virtually prevents bait from being shaken out of the station after it
has been moved; 

Equipped with internal structures for containing baits and minimizing
spillage and tracking of bait outside of the station or into readily
accessible parts of the station;

Made of a design and color that is not especially attractive to
children; and

Capable of displaying precautionary statements in a prominent location. 

The Agency believes that the tamper-resistant criteria from PR Notice
94-7 remain appropriate for rodenticide bait products, except that EPA
is proposing to make Criterion 5 optional for bait stations designed for
use in and around homes.  The Agency believes that rodenticide bait
stations for use in and around homes would not need to be anchored
because, under the mitigation proposal, rodenticide bait stations used
by consumers would only be permitted to contain active ingredients
formulated in bait blocks that could not be shaken out of the bait
station.  Loose bait that could be shaken out of a bait station would no
longer be permissible for use by consumers in residential settings. 
Moreover, EPA believes that most consumers would be unlikely to comply
with instructions to anchor or affix a bait station to indoor floor
surfaces due to the potential for damage to those surfaces.  

EPA expects that its proposal to require tamper-resistant bait stations
for all consumer rodenticide bait products with uses in and around homes
would dramatically decrease the number of children who are exposed to
rodenticide products each year.  The Agency believes that most exposure
incidents are due to inadequate protection of baits applied in areas
accessible to children.  Non-professional users often apply rodenticide
baits in open containers or in ready-to-use, nonprotective cardboard
packaging.  Most rodenticide bait products currently on the consumer
market are packaged in thin cardboard trays with pop-up lids or in
“place packs” (plastic, cellophane, or paper packets containing
bait).  EPA believes that these types of packaging may contribute
significantly to the high number of exposures to children reported each
year to the AAPCC.  By removing these products from the consumer market,
EPA’s mitigation proposal should significantly decrease the number of
rodenticide exposures to children.   

Antidote Issue

Vitamin K is an antidote to treat exposure to first-generation or
second-generation anticoagulant rodenticides.  There are no true
antidotes for the non-anticoagulant rodenticides (bromethalin,
cholecalciferol, and zinc phosphide), but there are effective medical
treatments designed to lessen absorption and/or to address symptoms.  

It has been suggested by some groups that the proposed regulatory
measures to prohibit the sale of second-generation anticoagulant
products on the consumer market in order to mitigate ecological risks
would result in greater risks to children because consumers would be
forced to buy rodenticides for which there are no antidotes.  The Agency
disagrees with this assertion for three reasons.  First, there are
antidotes for the three first-generation anticoagulants
(chlorophacinone, diphacinone, and warfarin), and the Agency believes
that these active ingredients are appropriate for use in consumer
products.  Second, if antidote treatment is necessary following exposure
to a first-generation anticoagulant, a single dose of Vitamin K is often
sufficient, whereas antidote therapy following exposure to a
second-generation anticoagulant may require repeated doses of Vitamin K
(due to the fact that the second-generation anticoagulants are more
toxic and persistent than the first-generation anticoagulants).  Third,
the Agency believes that the vast majority of exposures to children will
be prevented if the proposed requirement for tamper-resistant bait
stations is implemented. 

  

V.	Label Improvement Measures

Independent of the mitigation measures discussed above, EPA is currently
considering specific labeling improvements to make rodenticide labels
clearer and more understandable.  In particular, the Agency is focused
on labeling changes that would provide clearer direction to consumers on
how to use rodenticide products in order to minimize potential exposure
to children, wildlife, and pets.  The Agency has concluded, however,
that labeling enhancements alone would not mitigate the risks to
children and wildlife to a sufficient degree.

EPA has received a stewardship proposal from the Rodenticide Registrants
Task Force (RRTF), which articulates the industry’s suggestions for
rodenticide labeling improvements.  (The RRTF’s stewardship proposal
may be found in docket number EPA-HQ-OPP-2006-0955 at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov .)  After the Agency
reviews the public comments received on the proposed risk mitigation
measures described in this document and reaches a final decision on
those risk mitigation measures, EPA will then complete its evaluation of
the proposed label improvement measures and determine the specific
labeling changes that will be required.          

 

VI.	Impacts of EPA’s Mitigation Proposal

For more detailed information about the potential impacts of EPA’s
proposed risk mitigation for rodenticide bait products, please see
EPA’s “Impact Assessment for Proposed Rodenticide Mitigation,”
(Chiri et al., 9/20/06), located in the rodenticide docket
(EPA-HQ-OPP-2006-0955) on the internet at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov .	

Impacts of Proposed Restricted Use Classification to Address Ecological
Risks 

	As described in Section II of this document, EPA is proposing to
classify all rodenticide bait products containing the active ingredients
brodifacoum, bromadiolone, and difethialone as restricted use pesticides
under FIFRA section 3(d).  The intended beneficial impact of the
proposed mitigation would be a significant reduction in the risk of
secondary exposures to wildlife, a reduction in primary risks to
non-target animals (especially small birds) where small amounts of
second generation anticoagulants can be lethal, and a decrease in the
number of wildlife incidents caused by rodenticide exposure, as
described in Section II.  

	EPA has concluded that requiring rodenticide bait products containing
second-generation anticoagulants to be classified as restricted use
pesticides should not have an adverse impact on residential users in
terms of significantly increased costs or decreased effectiveness.  EPA
believes costs to residential users will not increase unduly because
such users will still be able to purchase rodenticide baits (in bait
stations) containing first-generation anticoagulant and
non-anticoagulant active ingredients.  The Agency believes that
consumers’ selection of rodenticide products is primarily driven by
trade names and not by the active ingredients contained in the baits. 
As public health pesticides, all rodenticide products must demonstrate
basic efficacy prior to registration.  Therefore, EPA further believes
that the replacement of second-generation anticoagulants with
first-generation anticoagulants will not significantly affect
residential users’ capability to control commensal rodents because the
first-generation anticoagulants are sufficiently efficacious for typical
residential settings.  

For those residential settings where second-generation anticoagulants
provide a distinct advantage, these products would still be available
from certified applicators.  Although hiring certified applicators is
significantly more expensive than purchasing consumer use products, EPA
believes that the vast majority of the residential settings that would
require the use of second-generation anticoagulants are high-occupancy
buildings that are already likely to be relying on professional pest
control companies, which can provide certified applicators with little,
if any, increase in cost.  EPA anticipates that any cost increase that
might result from this risk mitigation measure would be outweighed by
the anticipated reductions in exposures to non-target animals.

Resistance to the first-generation anticoagulants has been reported in
the past, and recently there have been some reports of resistance to the
second-generation anticoagulants.  Integrated Pest Management (IPM)
experts have demonstrated that this resistance can be controlled by
withdrawing the rodenticides for at least thirty days, by alternatively
using bait and non-bait techniques, or by alternating between
rodenticides with different modes of action.  EPA’s proposed risk
mitigation leaves a variety of compounds available for rodent control. 
The topics of resistance, resistance management, and Integrated Pest
Management techniques are discussed in detail in “Analysis of
Rodenticide Bait Use” (Chiri et al., 1/23/06), which may be found in
docket number EPA-HQ-OPP-2006-0955 at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov .  

Impacts of Proposed Requirement for Tamper-Resistant Bait Stations for
All Outdoor, Above-Ground Placements of Bait Products Containing
Second-Generation Anticoagulants to Address Ecological Risks

EPA is proposing to require that all outdoor, above-ground placements of
bait products containing second-generation anticoagulants be contained
in tamper-resistant bait stations, to prevent access to rodenticide bait
by non-target animals.  The intended beneficial impact of this proposed
mitigation measure would be a reduction in primary risks to non-target
animals (especially small birds) where small amounts of second
generation anticoagulants can be lethal, and a decrease in the number of
wildlife incidents caused by rodenticide exposure, as described in
Section II.

EPA anticipates that this mitigation measure will not result in an
increased cost for rodent control performed by certified applicators
(the only permissible applicators of second-generation anticoagulants,
under this mitigation proposal) because EPA believes that certified
applicators have, and likely are already using, tamper-resistant bait
stations in many situations.  Requiring the use of tamper-resistant bait
stations in all situations, rather than leaving the decision to the
applicator’s discretion, should not result in a cost increase to
certified applicators or those using the services of a certified
applicator.

Impacts of Proposed Requirement for Tamper-Resistant Bait Stations to
Address Children’s Exposure to Rodenticides

	EPA is proposing to require that all consumer-use rodenticide bait
products labeled for use in and around residences be available only in
tamper-resistant bait stations containing active ingredients formulated
in bait blocks.  

An anticipated adverse impact of the proposed risk mitigation is
increased cost for rodent control for consumers who choose rodenticide
baits, because EPA believes that rodenticide manufacturers are likely to
pass onto consumers the additional cost to develop and produce
tamper-resistant bait stations.  The Agency estimates that the increased
cost to consumers who continue to use rodenticide products would be
between $0.50 and $10.01 per household per year for mouse control, and
between $2.34 and $46.84 per household per year for rat control.  EPA
has concluded that this small potential cost increase will not impede
the public’s access to rodent control tools because residential users
who are unable or unwilling to buy rodenticide baits will be able to use
other affordable alternative methods, such as snap traps and glue
boards.  Below is a table of estimated costs per household for different
types of rodent control methods.  These cost estimates are discussed in
more detail in EPA’s “Impact Assessment for Proposed Rodenticide
Mitigation,” (Chiri et al., 9/20/06), located in the rodenticide
docket (EPA-HQ-OPP-2006-0955) on the internet at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov .	

Rodent Control Options	Mice	Rats

	Cost per household per year	Cost per household per year

Current cost of rodenticide	$0.60 - $2.40	$1.20 - $4.80

Bait station plus rodenticide bait block (EPA’s current risk
mitigation proposal)	$1.10 - $12.41	$3.54 - $51.64

Snap Trap/Glue Trap 	$0.28 - $5.58	$0.56 - $11.24

Pest Control Operator	$254.00 - $254.00	$254.00 - $254.00

The intended beneficial impact of the proposed mitigation would be a
significant reduction in the number of incidents of rodenticide exposure
to children, which would result in both health and social benefits, as
described in Section III.  

New York State Health Department data from 1990-1997 show that
African-American and Latino children and children living below the
poverty level are disproportionately exposed to rodenticides. 
Fifty-seven percent of children hospitalized for rodenticide exposure in
New York during those years were African-American, although only 16% of
New York State’s population in 1990 was African-American; 26% of
hospitalized children were Latino, while Latinos comprised only 12% of
the State’s population in 1990; and 17.5% of the children hospitalized
for rodenticide exposure were below the poverty level, while children
living below the poverty level comprised only 13% of the State’s
population in 1990.  These data are further discussed in EPA’s
“Updated Review of Rodenticide Incident Reports Primarily Concerning
Children” (Blondell, 6/3/99), available at   HYPERLINK
"http://www.regulations.gov"  www.regulations.gov  under docket number
EPA-HQ-OPP-2006-0955.  EPA’s proposed risk mitigation measures would
significantly reduce the likelihood of rodenticide exposure to children,
including those populations of children who may be disproportionately at
risk for exposure.  

EPA has concluded that the expected reduction in children’s exposure
to rodenticide bait products outweighs the estimated cost increase due
to the requirement for tamper-resistant bait stations.  

Integrated Pest Management (IPM) Necessary for Effective Rodent Control

EPA believes that the proposed risk mitigation measures will not affect
the ability of residential users or professional pest control operators
to control rodents, because fully effective rodent control products
would remain available and affordable.  In most situations, it is not
possible to control commensal rodents with rodenticides alone.  In
addition to trapping or baiting, rodent control requires sanitation,
rodent-proofing, and removal of rodent harborage.  Without habitat
modification to make areas less attractive to commensal rodents, even
eradication will not prevent new populations from recolonizing the
habitat.  The term Integrated Pest Management (IPM) is used to describe
multi-faceted approaches for pest control.  For urban pest control,
including rodent control, IPM has been defined as “the coordinated use
of pest and environmental information with available pest suppression
methods to prevent unacceptable levels of pest damage by the most
economical means and with the least possible hazard to people, property,
and the environment.”  EPA’s document “Analysis of Rodenticide
Bait Use” (Chiri et al., 1/23/06) details IPM programs in three
cities, as well as alternate means of rodent control which may be used
in an IPM program.  The document may be found in docket number
EPA-HQ-OPP-2006-0955 at   HYPERLINK "http://www.regulations.gov" 
www.regulations.gov .  For additional information about IPM, please
refer to   HYPERLINK "http://www.epa.gov/pesticides/factsheets/ipm.htm" 
www.epa.gov/pesticides/factsheets/ipm.htm .

The CDC, as part of the Department of Health and Human Services,
monitors diseases and disease-causing agents and advises the public on
disease control and prevention.   The CDC and EPA’s Office of
Pesticide Programs work closely to develop risk mitigation measures on
public health pesticides.  EPA has consulted with CDC on the risk
mitigation measures for rodenticides described in this document, and
will continue this consultation as EPA develops its final risk
mitigation decision on the rodenticides.

EPA has developed partnerships with the CDC and the Department of
Housing and Urban Development (HUD) to promote IPM in low-income housing
and other setting where pest pressures are significant.  Activities
carried out under these partnerships include:

issuance of a HUD order that strongly encourages the use of IPM for pest
control in low income housing;

development of HUD guidance and fact sheets on IPM in multi-family
housing;

collaboration with CDC on “Rodent Control Academies” developed to
provide basic training on IPM or rodent control and foster greater
cooperation among city agencies in strategic approaches to rodent
control;

integration of IPM into training courses offered by federally funded
entities including the National Center for Healthy Housing and the
National Environmental Health Association;

funding research for assessing health outcomes associated with IPM
interventions; and

funding IPM demonstration projects in multi-family housing and other
sites with significant pest pressures.

The CDC maintains a website to advise the public about rodent control at
   HYPERLINK "http://www.cdc.gov/rodents/"  http://www.cdc.gov/rodents/
.  This website provides excellent advice about urban and surburban
commensal rodent control.  The CDC also provides public health
continuing education and has a program, titled “Managing Rodents and
Mosquitoes through Integrated Pest Management,” available on webcast
at   HYPERLINK "http://www2.cdc.gov/phtn/ipm/default.asp" 
http://www2.cdc.gov/phtn/ipm/default.asp . 

Debra Edwards, Ph.D., Director

Special Review and Reregistration Division

 As an alternative to restricted use classification, the Rodenticide
Registrant’s Task Force (RRTF) has proposed a label statement
restricting to certified applicators (or those working under their
supervision) the outdoor use of rodenticide bait products containing the
nine active ingredients covered in this proposal.  The Agency has
concluded that it is not appropriate to include on the label of a
non-restricted use product any language suggesting that use is limited
to certified applicators.  EPA believes that “for use only by” label
statements such as the one proposed by the RRTF are not enforceable and
create no obligations on sellers or enforcement agencies.  For
additional information on this issue, please refer to the “For Use
Only By” issue paper, prepared by the EPA Office of Pesticide
Programs’ Labeling Committee, which is available on the EPA website at
  HYPERLINK
"http://www.epa.gov/pesticides/regulating/labels/projects.html" 
www.epa.gov/pesticides/regulating/labels/projects.html .   

 The RSW also considered tamper-resistant bait stations, but because
there were no ready-to-use bait stations on the market that that
appeared to meet EPA’s criteria for tamper-resistance, the RSW
recommended against requiring tamper-resistant bait stations.

 Under this mitigation proposal, bait block refills would not be
available for sale unless packaged together with at least one bait
station.

 The criteria in PR Notice 94-7 apply to bait stations that are sold
separately from rodenticide bait products and to bait stations that
applicators might construct for their personal use so as to make bait
placements that are compliant with label requirements.

 Frantz, S.C.  1996.  Integrated pest management in New York State.  IPM
Practitioner.  18(2):8-10.

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