Page 2 of 23

EPA has received comments from the Scientific Advisory Panel (SAP) regarding the “Scientific 

Conclusions Supporting EPA’s FIFRA Section 6(b) Notice of Intent to Cancel Twenty 

Homeowner Rodenticide Bait Products” (hereafter referred to as the NOIC). EPA provided the 

SAP with 11 Charge Questions for their consideration. The SAP has submitted minutes from 

their review (SAP Minutes No. 2011-06), which included comments related to the analysis EPA 

conducted on the potential risks that rodenticides used for commensal rodent control pose to 

children, pets and non-target animals as well as efficacy and cost analyses. This response to the 

SAP comments was compiled based on the considerations and analyses of Office of Pesticide 

Program staff and focuses on the issues raised by the SAP.

The proposed cancellation is discussed in more detail in the NOIC and the Statement of Reasons 

and Factual Basis for Notice Intent to Cancel and Notice of Denial of Certain Rodenticide Bait 

Product Registrations and Applications. 

1. Response to Comments within Charge Question 1:

1.1. SAP Comment (page 6): [T]he vast majority of exposures to first and second 

generation anticoagulant rodenticide products by young children will not result in a 

clinically significant coagulopathy or bleeding. However, if the toxic threshold is 

exceeded, there is a widely available laboratory test and an antidote (vitamin K1) with 

which clinicians are familiar because of the therapeutic use of warfarin. 

EPA Response: Fortunately, rodenticide exposures generally result in no clinical harm to 

children. EPA recognizes this, and is aware that a laboratory test and treatment (vitamin K1) for 

exposure to anticoagulant rodenticides are available. Nonetheless, continuing children’s status 

quo exposure to non-conforming rodenticide products is unacceptable. 

Rodenticides are potent mammalian poisons and the quantity in a typical placement is sufficient 

to cause adverse health effects to children. The Poison Control Center data show that around one 

percent of the rodenticide exposures to children result in such effects. This single percent 

corresponds to a significant number of children owing to the high number of children exposed.

Furthermore, some rodenticide exposure incidents involving children do result in severe 

coagulopathy and bleeding. 

EPA also notes that even initially asymptomatic children may experience a period of increased 

risk of excessive bleeding following exposure to anticoagulant rodenticides. Accidental 

ingestion of anticoagulants can lead to coagulopathy (impairment of the body's ability to stop 

bleeding) in a child; although the child is initially asymptomatic they have the potential to bleed 

excessively (internally or externally) if they experience bodily trauma while their ability to stop 

bleeding is impaired. This potential is not limited to easily recognized locations such as the 

elbow. Bleeding can take place within a less easily recognized location, such as the brain. 

Even in the case of anticoagulant exposures where the dose is too low to produce observable 

symptoms and where no subsequent trauma presents bleeding risks, such fortunate outcomes are 

not initially obvious, and there are social costs associated with evaluating and treating children 

whose exposures are uncertain. While the availability of a laboratory test and a treatment 
Page 3 of 23

protocol may facilitate such evaluation and treatment, the availability of these tools does not 

negate the social cost of needing to undertake the evaluation and treatment in the first place. 

EPA’s risk mitigation strategy is based on preventing exposures to children through the use of 

bait stations with solid bait that is reasonably expected to remain in the bait station and is less 

likely for mice to cache and for children to access. 

1.2. SAP Comment (page 6 and 19): [S]evere bromethalin poisonings are very concerning 

for clinicians because of less human experience with them and, unlike the 

anticoagulants, there is no specific diagnostic test or antidote . . . Given that 

bromethalin targets the CNS [central nervous system] and interferes with mitochondrial 

function, there is concern that the developing brain of young children may be 

particularly susceptible to the neurotoxic effects of bromethalin. 

EPA Response: The Agency anticipates that enclosing rodenticide baits in protective bait 

stations will greatly reduce the frequency of child incidents involving all types of rodenticides. 

Whether a particular exposure is to an anticoagulant or a bromethalin rodenticide is of 

significantly less importance to human health than whether the exposure occurs in the first place. 

Nonetheless, EPA notes that the effects of severe bromethalin poisoning are the same as other 

uncouplers of oxidative phosphorylation such as aspirin, indomethacin and ibuprofen, and that 

clinicians are experienced in treating the effects of those types of chemicals. 

Although a toxic dose of an anticoagulant causes somewhat more distinctive bruising and 

bleeding symptoms (including blood in urine, bleeding from the nose and gums, coughing blood 

and, depending on the amount consumed, bleeding into the joints and brain), those symptoms do 

not appear until several days after ingestion. Thus, neither type of rodenticide (i.e., either 

anticoagulant or bromethalin) is more likely than the other to produce symptoms that would alert 

parents or health care workers of a rodenticide poisoning within the critical first hours when 

gastric decontamination could be an effective treatment.

The SAP expressed concern that the developing brain of young children might be particularly 

susceptible to the effects of bromethalin. The concern appears to be that cerebral edema might 

occur more readily in young children and its effects on the developing brain might be more 

severe. Cerebral edema, and signs of cerebral edema such as tremors, could possibly occur in 

moderate or major bromethalin incidents, but incidents of such severity have rarely occurred. 

Uncoupling of electron transport is a reversible effect, Once the uncoupler is removed from the 

system, normal mitochondrial respiration resumes. Transient swelling of the brain and spinal 

cord is not associated with long term neurological damage.

EPA concludes that bromethalin and anticoagulant exposure present comparable human health 

concerns, and that both sets of concerns are appropriately mitigated through the RMD 

requirement for tamper-resistant bait stations. Sufficiently high exposures to either bromethalin 

or the anticoagulants (particularly the SGARs) have the potential to result in patients being 

admitted to intensive care units at considerable harm and expense to the patient. EPA is 

concerned about all types of rodenticide poisonings, and believes that they are all best prevented 
Page 4 of 23

by increasing the availability and use of bait stations that are not easily opened by children and 

are reasonably anticipated not to release rodenticide bait. 

2. Response to Comments within Charge Question 2:

2.1. SAP Comment (page 7): [T]he NOIC does not establish a quantitative level of risk for 

severe outcomes and hence, it is difficult to concur with EPA’s “degree of risks” posed 

to humans.

EPA Response: The Panel appears to have interpreted the charge question (“Does the SAP 

concur with the EPA’s conclusions regarding the . . . degree of risks posed to humans?”) as 

alluding to a quantitative risk determination and asking the Panel whether they concurred that 

risk had been properly quantitatively characterized. The Panel responded that EPA had not 

actually prepared a quantitative assessment of human risks.

EPA agrees with the SAP that it has not quantitatively characterized the risk to human health 

from the non-conforming pesticide products. The Agency did not expect that the SAP would be 

able to offer quantitative confirmation of the Agency’s qualitative risk characterization. Rather, 

EPA had qualitatively characterized the risk to human, health, with sufficient clarity to support 

the proposed cancellations. FIFRA does not require a quantitative characterization of risk. 

Given that all of the rodenticide products at issue are capable of providing satisfactory rodent 

control, a qualitative comparison of their respective risks is sufficient to establish whether the 

risks of some of those products are unreasonable in comparison to available, registered 

alternative products.

2.2. SAP Comment (pages 6-7): [T]he incident data come from several sources, all of 

which have strengths and limitations. 

EPA Response: The Agency generally agrees that individual sources of incident data differ 

from each other in terms of their respective strengths and limitations. Incident information can, 

however, provide important feedback to the Agency, assisting in determining real-world 

exposures and risks posed by pesticide products. 

3. Response to Comments within Charge Question 3:

3.1 SAP Comment (page 22): [S]upporting data presented are not sufficient to draw 

conclusions regarding how RMD compliance would provide a benefit related to 

societal costs. Any effect on utilization of emergency medical resources . . . is 

uncertain.

EPA Response: EPA values the scientific advice that members of the Panel offer within their 

respective areas of expertise. However, determining whether compliance with particular 

regulatory requirements would provide benefits to society, or the extent of those benefits, does 
Page 5 of 23

not appear to fall within the mandate of the SAP which is to provide advice on the science EPA 

uses to make decisions.

EPA’s review of available exposure information suggests that children commonly gain access to 

baits placed in homes even in cases where users may believe they are complying with label 

instructions aimed at preventing child, pet, and non-target wildlife exposure. EPA expects

rodenticide exposures to children will substantially decrease if all consumer rodenticide products 

conform to the RMD (i.e., packaged with or in bait stations that are tamper-resistant; produced in 

block forms that are expected to remain in bait station). If post-cancellation experience 

demonstrates that the RMD requirements are still insufficient to lower children’s exposure to 

rodenticides, then EPA will evaluate the need for further follow-up action on the basis of such 

experience.

3.2 SAP Comment (page 22): It is also important to note that since 2007, U.S. poison 

centers have adopted a treatment guideline for anticoagulant rodenticides that 

discourages routine referral to health care facilities and laboratory studies for typical 

exposures in young children (Caravati, 2007).

EPA Response: This comment raises two separate issues, one regarding the reliability of 

incident reporting databases, and another regarding the costs to society of the products EPA 

proposes to cancel. 

In regard to the first issue, EPA agrees that it is important to recognize that incident reporting 

rates can be affected by events unrelated to the actual risks posed by rodenticides. The 2007 

treatment guidelines may have exerted a downward influence on the number of rodenticide 

exposure incidents reported as significant, as a fraction of the number of rodenticide exposure 

incidents that actually were significant. 

In regard to the second issue, EPA acknowledges that decreasing the frequency with which 

rodenticide-exposed children are referred for medical care or observation could mitigate some of 

the costs of such exposures, by improving discrimination between circumstances in which 

medical referrals is a necessary response and circumstances in which it is not a necessary 

response. However, EPA does not agree that these guidelines (intended simply to reduce the 

frequency of an unnecessary medical response) can justify maintaining children’s exposure to 

rodenticides at status quo levels. The 2007 guidelines do not alter the frequency with which 

children actually come into contact with rodenticides. Nor do they alter the percentage of those 

children who will consume a quantity of rodenticide that can result in adverse effects.

3.3 SAP Comment (page 21): Health outcomes associated with rodenticides exposures 

are better than those associated with numerous other pesticides and common household 

products.

EPA Response: The Agency acknowledges that there are other pesticides and household 

products that may be associated with health outcomes worse than those of the rodenticides. The 

fact remains, though, that rodenticides are potent mammalian poisons. The status quo of 

continuing widespread, unnecessary exposure of children to rodenticides remains unacceptable.
Page 6 of 23

3.4 SAP Comment (page 7): The Panel urged EPA to make certain that rodent control 

can be adequately maintained for protection of human health following the proposed 

cancellations. The Panel urged EPA to make certain that a thorough and wellresearched assessment of the public health issues associated with a potential reduction 

in rodent control (e.g., the potential for increases in rodentborne diseases, bites) is 

provided by the Department of Health and Human Services (DHHS), and that this 

assessment be used in the overall risk assessment of the rodenticide products under 

consideration in this NOIC.

EPA Response: Especially in light of input from the Centers for Disease Control (CDC), the 

Agency believes the Panel’s concerns about potential impacts to public health are misplaced. 

In 2012, CDC reaffirmed its support for EPA’s risk mitigation requirements via written 

comments on the “Draft Notice of Intent to Cancel and Notice of Denial of Registration to 

Certain Rodenticide Products” (hereafter “Draft NOIC”) (Buchanan, 2012). This reaffirmation 

encompassed the CDC’s earlier conclusion, in 2007, that the cancellation is “in the interest of 

public health.” The CDC noted in 2007 that it “rarely recommends rodenticides for plague 

control.” Rather, “host-targeted flea control” would be the typical pesticidal intervention. Even 

in the unlikely event that conditions “seemed to warrant rodenticide use,” the CDC “would 

almost undoubtedly recommend” that such applications “be done by professionals rather than by 

the general public.” 

The cancellations at issue will only affect the type of rodenticide products available to 

consumers. EPA notes Panel members’ own recognition that consumers’ “individual efforts 

will seldom result in even the localized elimination of rodents.” This assessment is consistent 

with the CDC’s recommendation that rodenticide applications intended to achieve a public health 

benefit be undertaken by professionals. This cancellation action will not limit the range of 

products available to professional applicators.

4. Response to Comments within Charge Question 4:

4.1 SAP Comment (page 8): The Panel concurred that the results from the database 

searches and literature provided by EPA and others support the conclusion that 

exposure to, and adverse effects from, rodenticides, including anticoagulant 

rodenticides, have occurred in pets in the United States from 1999 to 2010. However, 

the Panel's response provides only the risk perspective, and does not include the benefit 

perspective of the analysis. The database results and literature review were interpreted 

as observational data, not an assessment of risk, per se; consequently, they do not 

support use of the terms “risk” or “high frequency” in the NOIC, at least to the extent 

that those terms imply that a risk assessment was conducted.

EPA Response: EPA values the advice that members of the Panel offer within their respective 

areas of expertise. However, specifying the particular risk and benefits assessments that should 

inform a risk management decision under FIFRA is a question of regulatory policy; it does not 

appear to fall within the mandate of the SAP which is to provide advice on the science EPA uses 
Page 7 of 23

to make decisions. EPA acknowledges that the available information on rodenticide exposure 

and toxicity are insufficient to prepare an ideal risk assessment. However, EPA has conducted a 

risk assessment that is adequate to support the proposed cancellations. 

The term “high frequency” was used to describe the number of pet incidents involving 

rodenticides compared to other substances. Relative to other pet poisoning incidents, there is a 

high frequency of incidents involving rodenticides. In fact, rodenticide pet poisonings are among 

the most frequent type of pet incident reported across databases. The term “risk” was used to 

explain that among the reported rodenticide pet incidents, a sizable fraction of exposed animals 

died or suffered severe effects requiring veterinary treatment. 

4.2. SAP Comment (page 8): Recent evidence for numerous incidents involving pets and 

nonconforming rodenticides appears to be adequate and brodifacoum use in and 

around the home has been involved in the majority of reports. Decreasing over-thecounter availability of brodifacoum is likely to reduce adverse pet events associated 

with it, if properly applied. The potential consequences of increased use of the nonanticoagulant rodenticide bromethalin are unknown and worrisome due to the lack of 

diagnostic tests and effective treatment options for bromethalin intoxication.

EPA Response: EPA’s strategy for reducing rodenticide risks to pets focuses on the requirement 

for bait stations, which is expected to greatly reduce the frequency of pet exposure incidents, 

irrespective of the types of rodenticide. Whether a particular exposure is to an anticoagulant or a 

bromethalin rodenticide is of significantly less importance to human health than whether the 

exposure occurs in the first place. 

EPA notes that for those pets that do consume enough bromethalin to cause adverse effects, the 

course of treatment for bromethalin pet poisonings includes common veterinary treatments. 

Costs and prognoses associated with rodenticide pet incidents (whether SGAR or bromethalin) 

vary widely depending on amount consumed and amount of time between consumption and 

treatment. 

SAP Comment (page 8): The Panel noted additional risk concerns not mentioned in the NOIC, 

such as the increased risks associated with a choking hazard from bait blocks, exposure to a 1 

ounce bait block and gastrointestinal trauma from bait station ingestion, particularly for dogs. 

EPA Response: The Panel is contemplating an unlikely scenario. If the proposed cancellations

become effective, the only rodenticide products that would be registered for general consumer 

use where they could be accessible to dogs would have to include Tier 1 bait stations. Tier 1 bait 

stations have been demonstrated to meet the criteria for tamper-resistant bait stations that are set 

forth in Pesticide Registration (PR) Notice 94-7, and have successfully isolated bait from 

children and dogs in laboratory testing according to EPA protocols. There are no reports of pets 

choking on rodenticide bait blocks or bait stations in the pet incident data that EPA has reviewed. 

This remains true in recent years despite the increased use of single-use bait stations recently in 

response to EPA’s 2008 risk mitigation decision. The incident data do show, however, that pets 
Page 8 of 23

have experienced major trauma (i.e., life threatening symptoms and/or residual disability) and 

death as a result of consuming unprotected rodenticide bait.

5. Response to Comments within Charge Question 5:

5.1. SAP Comment (page 8): The Panel agreed that, to the extent that the mechanisms of 

action (inhibition of “recycling” of vitamin K1, uncoupling oxidative phosphorylation, 

and increased circulating 25- hydroxy cholecalciferol causing hypercalcemia) are the 

same in pet and other non-target mammals, it is reasonable to conclude that hazards to 

pets and other non-target mammals are similar, but not the same. The literature 

supports the notion that the “toxic dose” on a mg/kg body weight basis varies among 

mammals, so the term comparable must account for this dose difference to arrive at 

comparable risk. For the rodenticides under review, published experimental studies 

provide information on dose levels that produce adverse outcomes in dogs, cats, and, in 

some instances, other pets. Use of this pet-specific data may be more appropriate than 

extrapolation of risk from non-target mammalian wildlife. Based on the available 

wildlife data there is sufficient evidence that significant risks also exist for larger pets, 

as risk quotients (RQs) were found to increase with the body weight of the assessed 

generic/wild animal, though the potential risks to pets could be better evaluated by 

reviewing the available data that are specific for companion animal species. Pet-specific 

information would also better address potential differences in sensitivity among species 

and between different rodenticides. The Panel stated that it is generally reasonable to 

conclude that risks to pets are similar to risks to non-target mammalian wildlife of 

comparable body sizes; however, the mammalian body weight groups of 15, 35, and 

1,000 grams used to assess primary exposure risk are not practical for pets except in the 

case of the very smallest pets. The 1,000 and 3,000-gram size mammalian classes 

included in the secondary exposure risk assessment provide a better approximation of 

small dogs and cats, but not for larger pets.

EPA Response: The Agency acknowledges that the Panel generally agrees with the 

methodology used in EPA’s pet assessment, but believes refinements could be made by 

considering larger body weight groups, as well as pet-specific toxicological information from 

experimental studies. EPA agrees that more species-specific and breed-specific toxicological 

information would refine the Agency’s risk assessment. However, that information is not 

currently available, and the analytical refinements the information would enable are not 

prerequisites to an adequate risk assessment.

6. Response to Comments within Charge Question 6:

6.1. SAP Comment (page 9): The Panel did not agree with EPA that limiting consumer use 

to conforming rodenticide products will generally reduce the opportunity for exposure of 

pets to commensal rodenticide products. They concluded that the pet incident reports 

demonstrate that residential consumers in general do not read and/or follow label 

directions for current rodenticides and hence, would not be any more likely to do this for 
Page 9 of 23

rodenticide products formulated in block form. To the extent that conforming rodenticide 

products are provided outside of bait stations, the pet incident report does not support 

the conclusion that the opportunity for exposure of pets to commensal rodenticide 

products is likely to be reduced. To the extent that conforming rodenticides are provided 

solely in tamper-proof bait stations that actually reduce exposure to dogs and other pets, 

the above conclusion may change. Use of rodenticides in bait stations will decrease the 

ease of accessibility and likely decrease the number of exposures involving pets, but use 

of them will not completely eliminate exposures, especially with dogs.

EPA Response: EPA agrees with the Panel’s statement that the “[u]se of rodenticides in bait 

stations will decrease the ease of accessibility and likely decrease the number of exposures 

involving pets, but will not completely eliminate exposures, especially with dogs.” EPA also 

agrees with the Panel’s observation that the human and pet incident data suggest that many 

residential consumers are not following current label directions to place bait out of reach of 

children or pets or in a tamper-resistant bait station. EPA’s RMD was intended to reduce the 

opportunity for misuse and greatly reduce the frequency of pet exposure to these products by 

making it easier for residential consumers to comply with label requirements. The Agency will 

continue to monitor incident data to evaluate if the mitigation produces the desired decrease in 

incidents, and will consider additional restrictions if necessary.

Unless data show misuse is resulting in significant adverse effects, EPA will presume that 

residential consumers will generally comply with reasonable, practicable label requirements. 

EPA expects that most consumers will purchase single-use bait stations, and that products 

containing multiple bait block refills and a refillable bait station will be a niche market for 

persons with recurring rodent problems. If further incident data associate significant adverse 

effects with rodenticides sold as multiple bait block refills with a single, refillable bait station, 

EPA will take appropriate action.

6.2. SAP Comment (page 51): A societal cost not sufficiently included in the data and 

information provided is the increased cost of diagnosis and treatment of pets, and 

perhaps other non-target species, exposed to non-anticoagulant rodenticides. Generally 

speaking the cost of treatment is higher, and the prognosis is lower, for the nonanticoagulant rodenticides compared to the anticoagulant rodenticides.

EPA Response: EPA’s strategy for reducing rodenticide risks to pets (and associated costs) 

focuses on the requirement for bait stations, which is expected to greatly reduce the frequency of 

pet exposure incidents, irrespective of the types of rodenticide. Whether a particular exposure is 

to an anticoagulant or a bromethalin rodenticide is of significantly less importance to human 

health than whether the exposure occurs in the first place. 

EPA notes that for those pets that do consume enough bromethalin to cause adverse effects, the 

course of treatment for bromethalin pet poisonings includes common veterinary treatments. 

Costs and prognoses associated with rodenticide pet incidents (whether SGAR or bromethalin) 

vary widely depending on amount consumed and amount of time between consumption and 

treatment. 
Page 10 of 23

7. Response to Comments within Charge Question 7:

7.1. SAP Comment (page 9): In contrast to the Agency’s selection of uniform species, a 

better approach would be to conduct chemical-specific assessments with conceptual

models that identify receptors of interest for a refined risk assessment. . . . A species 

sensitivity distribution provides a more quantitative approach which, in turn, would 

provide a quantitative estimate of uncertainty.

EPA Response: In response to the SAP suggestion, EPA conducted a limited probabilistic risk 

assessment to better address differences in species sensitivity by utilizing the distributions of 

toxicity data and liver or blood plasma half-life data. This analysis was conducted to address 

concerns regarding the risk assessment for the secondary exposure pathway. The results of the 

limited probabilistic assessment for secondary exposures help quantify some uncertainties

through the use of exposure distributions, but did not change any of the general conclusions 

reached in the deterministic assessment. For example, brodifacoum and difethialone present 

secondary exposure risks exceeding EPA level of concern for some bird species under all

accumulation scenarios, and the “probability to exceed” was greatest for both brodifacoum and 

difethialone compared to the other evaluated rodenticides. Because the results of this secondary 

exposure probabilistic assessment are consistent with the deterministic assessment and do not 

support conclusions different from those drawn from the deterministic assessment, EPA

concluded that limited additional information would be gained by conducting an additional

probabilistic assessment for primary exposure. Accordingly, EPA did not conduct a probabilistic 

risk assessment to further evaluate primary exposure risks.

7.2. SAP Comment (page 10): A problem in the analysis of the first generation 

anticoagulant rodenticides (FGARs) (i.e., chlorophacinone, diphacinone) is the 

exposure scheme used in the avian and mammalian acute oral toxicity tests where a 

single oral dose or multiple doses are administered in a 24-hour period. As noted by 

EPA, the toxicity of FGARs increases by nearly two orders of magnitude when the dose 

is administered for 5 days. Therefore, acute oral toxicity tests for FGARs may greatly 

underestimate toxicity.

EPA Response: EPA acknowledges that there are two studies (Ashton et al. (1986); Shirazi et 

al (1994)) indicating that anticoagulant rodenticides show increased toxicity when the dose is 

delivered over multiple days rather than a single day. However, the extent of the increase 

appears to vary between chemicals and is likely to vary between species. Owing to the 

limitations of those studies, the single dose toxicity data remain the most meaningful and reliable 

basis for comparing the relative toxicity of rodenticides. 

EPA remains confident that the analyses conducted in the SAP Background Paper provide a 

meaningful representation of the risks of the rodenticides subject to the NOIC. Given the lack of 

definitive information on the effects of exposure duration and post-exposure duration on the 

toxicity of both first and second generation anticoagulants, EPA believes it is appropriate for it to 

continue to base its quantitative risk estimation on single-dose toxicity values from the dosebased and the dietary-based toxicity and exposure studies.
Page 11 of 23

7.3. SAP Comment (pages 11, 31): The relative contribution to dietary exposure from 

consumption of invertebrates that bioaccumulate rodenticides is uncertain. . . . The EPA 

White Paper, and the conceptual model shown on page 29, discuss invertebrates

as a possible source of exposure to compounds. The relative contribution to dietary 

exposure is uncertain, but given the incident report of the Philadelphia Zoo, invertebrate 

trophic transfer to insectivorous species may be significant, especially in rural and 

agricultural applications. Fisher et al. (2010) discuss the consumption of rodenticide 

bait and the accumulation of brodifacoum and diphacinone in terrestrial invertebrates. 

The calculation of bioaccumulation factors (BAFs) within invertebrates and other prey 

items for each compound should reduce uncertainties of exposure to wildlife.

EPA Response: EPA presumes that residential consumers will apply rodenticides where rodents 

are active, and that in those situations target rodents will out-compete insects to consume the 

overwhelming majority of the bait. However, the Agency concurs that invertebrate consumption 

of bait is a potential rodenticide exposure pathway for organisms consuming invertebrates, and 

this pathway should be further evaluated. Accordingly, EPA has conducted a further literature 

review to quantify the level of exposure to invertivores and to document evidence of this 

exposure pathway to invertivores. 

From its review, EPA concludes that invertebrates are exposed to and will consume bait (placed 

inside or outside bait boxes) with resulting body burdens no greater than the empirical or 

theoretical body burdens utilized in the small mammal prey for the secondary exposure analysis 

in the SAP Background Document. EPA also concludes that animals that are strict or primarily 

invertivores will consume invertebrates contaminated with rodenticides. Finally, EPA notes that 

the risk assessment conducted in the SAP Background Document for secondary consumers 

exposed to rodenticides through consumption of contaminated small mammals would also be 

protective of invertivores as the secondary consumer.

8. Response to Comments within Charge Question 8:

8.1 SAP Comment (pages 13, 30, 27): Reliance on standardized avian toxicity endpoints 

using less sensitive species is likely to underestimate the risk to birds of prey from both 

FGARs and SGARs making it difficult to determine if FGARs present less risk than 

SGARs to birds of prey. . . . [I]t was unclear to the Panel why a probabilistic approach

was not used to quantify liver concentrations of individual compounds. . . . [T]here are 

clearly enough data for a species sensitivity distribution for several compounds.

EPA Response: As suggested by the SAP, EPA conducted a limited probabilistic analysis to 

inform the level of confidence and explore uncertainty in the likelihood that a randomly selected 

secondary consumer may achieve a lethal rodenticide dose. This was accomplished using a 

Monte Carlo simulation with a distribution of possible outcomes that were analyzed to allow for 

more thorough understanding of the uncertainties associated with the available data. The 

modeling exercise was performed by varying selected parameters for liver or blood-plasma halflife and the LD50 or LC50. For each chemical, results from the probabilistic assessment support 

the overall conclusions the EPA has drawn from the other lines of evidence (i.e., RQ estimates, 
Page 12 of 23

quantity of contaminated mice or rats in diet required to consume the equivalent of an LD50, and 

results of the secondary feeding studies). 

8.2 SAP Comment (page 13): The conclusion that bromethalin presents lesser risk to nontarget wildlife may be flawed due to limited information on tissue persistence of 

bromethalin.

EPA Response: EPA acknowledges that there is some uncertainty associated with the analysis 

of the relative ecological risks of bromethalin and SGARs, because of limited data on tissue 

persistence. However, this uncertainty is not such as would call into question the Agency’s 

overall conclusions about the relative risks of bromethalin and second generation anticoagulants. 

The data that are available suggest bromethalin is unlikely to be highly persistent in tissue—it is 

rapidly eliminated from blood plasma. Moreover, persistence in tissue is simply a less important

factor in assessing secondary exposure risks of bromethalin than it is for anticoagulants, because 

of the rapid mortality and cessation of eating associated with bromethalin poisoning. Together, 

these two considerations make it unlikely that target rodents will accumulate bromethalin body 

burdens significantly greater than a dose lethal to the target rodent.

8.3 SAP Comment (page 13): “[I]t is not clear that brodifacoum and difethialone should 

be considered together since their overall risks are not similar.”

EPA Response: EPA disagrees that the “overall risks” of brodifacoum and difethialone are “not 

similar.” Difethialone and brodifacoum are similar, both with respect to hazard and with respect 

to risk profile.

While the Agency agrees that the available evidence of secondary risks from brodifacoum is 

more conclusive than the corresponding evidence of secondary risks from difethialone, the 

analyses (i.e., RQ estimates, quantity of contaminated mice or rats in diet required to consume 

the equivalent of an LD50, and results of the probabilistic analysis) identified risks for both 

chemicals more frequently than for the other evaluated rodenticides. The two chemicals are 

similar in that respect. Furthermore, brodifacoum and difethialone have similar physicalchemical properties and similar acute toxicological properties.

Response to Comments within Charge Question 9:

9.1 SAP Comment (page 37): However, rodenticides are also deployed by professionals 

representing commercial and institutional entities in urban and suburban areas and it 

is not clear how one would separate domestic from commercial/institutional usage as 

sources in urban and suburban land use areas.

EPA Response: The Agency agrees that the available incident location data are not a basis to 

quantify the fraction of overall exposure in urban/suburban locations that results from use by 

residential consumers (as compared to the fraction that results from use by professional users at 

commercial and industrial sites). EPA did not propose to draw such quantitative inferences from 
Page 13 of 23

the spatial analysis of incident data. Indeed, it is rare that a wildlife pesticide exposure incident 

is tied definitively to a particular user or product and this will likely remain an intractable 

uncertainty. 

However, a quantitative allocation of rodenticide product use between professional/commercial 

users and residential consumer use is not an analytical prerequisite to the cancellation action. In 

the absence of additional contrary information, EPA believes it is reasonable to infer that a 

significant fraction of the large number of incidents that take place in residential areas are a 

consequence of residential consumer use. EPA’s spatial analysis of rodenticide incidents 

demonstrates that many non-target species are present in urban/suburban environments, and are 

succumbing in those environments to poisoning by rodenticides used by residential consumers. 

9.2 SAP Comment (p. 39): [A] further source of error or bias in the land use component 

of this analysis may come from changes in land use with time, particularly increased 

urbanization. . . . [S]ome incidents which were classified as urban or suburban based 

on current land use, occurred when the land was still in rural use at the time of the 

incident.

EPA Response: The Agency agrees that some amount of urbanization does occur and could 

have occurred during the time span of the reported incidents. However the majority of the 

incidents were categorized based on information recorded in the “Habitat” field of the incident 

report, which records the land use at the site at the time of the incident. Additionally, many of 

the reported brodifacoum incidents characterized as occurring in urban/suburban habitats

occurred in major cities, including New York, Albany, Buffalo, and Los Angeles. These areas 

have been urban for several decades, including the time period when the rodenticide incidents 

were reported. Therefore, the Agency believes that the impact of urbanization on the accuracy of 

the original classifications of incidents is minor, and that urbanization does not impact the 

Agency’s conclusion that the available incident reports for rodenticides demonstrate that one or 

more exposure pathways are complete and that incidents occur in urban/suburban and rural areas. 

9.3 SAP Comment (p. 39-40): Of further relevance to this assessment are data on diet 

and habitat use of three owl species inhabiting urbanized environments in south 

western British Columbia, the barn owl (Tyto alba) and of diet of two other species, the 

barred owl (Strix varia) and the great horned owl (Bubo virginianus). Although these 

data are unpublished, they were recently presented and abstracted by Hindmarch and 

Elliott (2011a, 2011b) and the Panel was informed of the results for these 

deliberations.

EPA Response: The Agency agrees that this new unpublished data as well as other data cited in 

the minutes of the SAP response further support EPA’s position that nontarget wildlife, 

particularly raptorial species, are susceptible to secondary poisoning from rodenticides. 

9.4 SAP Comment (p. 42): Wild canids, such as foxes and coyotes, fall within the 

omnivore category and could conceivably be exposed through consumption of 

contaminated insects, treated grains, pellets or bait blocks as well as being potentially 

exposed via predation or scavenging.
Page 14 of 23

EPA Response: The Agency agrees that in some cases it may have miscategorized (as secondary 

poisoning incidents) wildlife mortality incidents that actually involved primary poisoning of the 

red, grey, and San Joaquin Kit fox. Available literature and life histories show an occasional use 

of corn and other grain based food items, and thus these species may also be primary consumers 

of rodenticide bait. However, the Agency does not believe this issue extends to coyote incidents. 

The literature indicates that when coyotes do seek out vegetative food items, they usually seek 

fruit and berries. Thus, coyotes would not likely recognize rodenticide bait as a potential food. 

Furthermore rodenticide bait is expected to be used in areas of a high rodent population and 

therefore the rodent prey (dead and alive) would likely be more available than rodenticide bait. 

Thus, even for the fox species, the Agency believes that the majority of mortality incidents 

would likely be the result of consumption of poisoned rodents rather than from direct 

consumption of bait. Moreover, the prevalence of rodenticide poisoning among exclusive 

carnivores suggests that secondary poisoning is likely to be the major exposure pathway among 

species such as fox and coyote that are primarily carnivores. The possibility that some predators 

may additionally face a primary exposure pathway does not reduce the risk they face through 

secondary exposure.

9.5 SAP Comment (page 43): For omnivorous and/or scavenging species, due to the 

delayed onset of signs caused by anticoagulant rodenticides, analysis of stomach 

contents that are present at the time of the animal’s death will not necessarily 

determine primary or secondary exposure. That is, absence of bait granules in the 

gastrointestinal tract at time of death does not rule out primary poisoning as the animal 

could have ingested the lethal dose 3 to 5 days earlier. Likewise, bait present in the 

gastrointestinal tract at the time of death may not have caused the animal’s death, 

although it does show that the animal had access to bait and would ingest the bait. In 

this case, the presence of granules upon death can suggest that the animal may also 

have consumed a lethal feeding of bait several days prior to death, but it is not absolute 

proof of primary poisoning. In summary, the Panel concluded that this approach of 

separating primary and secondary poisonings by diet is basically sound, but postmortem evidence from gut contents must be interpreted with caution.

EPA Response: The Agency agrees that the delayed toxicity of anticoagulant rodenticides 

could cause mortality several days after the ingested item that caused the initial poisoning (be it 

bait or by ingesting another animal that consumed bait). The gut/crop contents were used to 

make determinations of likely exposure pathways in 12 total incidents, all of which were 

associated with brodifacoum. If these incidents were re-categorized as unknown exposures, the 

total counts would change little. Such changes would have no impact on the overall conclusions 

previously made about the incident reports. The incident data would still provide evidence that 

the primary and secondary exposure pathways are complete for the use of these chemicals. 

10. Response to Comments within Charge Question 10:

10.1 SAP Comment (page 44): The Panel did not believe that efficacy data alone can 

be used to conclude that conforming rodenticide products are an effective option 

for the control of commensal rodents by nonprofessional users. The effectiveness of 
Page 15 of 23

products vary greatly across species, populations, and time (Tobin et al., 1993; 

Witmer, 2007a and 2007b; Pitt et al., 2011). This variation has been demonstrated 

repeatedly with several of the conforming products. Prior rodenticide exposure 

and rodenticide resistance (via either genetic or behavioral changes) may account 

for some, but not all, of the variation in control effectiveness. Environmental 

realities, including but not limited to, access to areas where rodents are normally 

found, structural condition of the home or building, availability of alternate food 

sources, learned foraging behaviors, variation in wild strains and neophobia, all 

play a part in the effectiveness of a rodent control effort (Clapperton, 2006).

EPA Response: The performance of rodenticide products under conditions of actual use is 

influenced by various factors, including those noted by the Panel. Consideration of these factors, 

however, leads EPA to conclude that the influence of most of these factors apply to all 

rodenticide products and, in many cases, non-chemical lethal control methods in a similar 

manner. As a variety of active ingredients encompassing at least two distinct modes of actions 

would remain available to consumers, as would non-chemical control methods, the cancellation 

of noncompliant products is not expected to decrease the level of control obtained by residential 

consumers or to affect the time to achieve that level of control.

10.2 SAP Comment (page 44): Limiting use to bait stations can greatly reduce the ability of 

users to establish the bait in some locations where the rodents are more likely to 

encounter and consume it and practical field efficacy of the available rodenticides will 

be likely reduced. Placing bait into small spaces such as inside of walls, under 

foundations, or in attic crawl spaces will be impractical with bait stations and/or larger 

bait blocks. 

EPA Response: EPA recognizes that it may be impractical to insert bait stations into certain 

cramped spaces such as wall voids, floor voids, and burrows. However, locations that are 

insufficiently accessible to accommodate the insertion of a bait station are also very likely 

insufficiently accessible to accommodate the application of the non-conforming loose bait 

products, consistent with labeling requirements to collect and dispose of leftover bait properly at 

the end of the treatment period. To the extent that application in a particular location is already

inconsistent with product labeling, EPA does not recognize, as a loss of social benefit, the loss of 

the practical ability to persist in such illegal application.

10.3 SAP Comment (page 44): [P]lacing baits in bait stations may decrease or delay 

uptake of bait by rodents, further reducing effectiveness, thereby allowing commensal 

rodents to continue to be a significant risk to human health (Buckle and Prescott, 

2011). Especially with rats, time to acclimate to the stations and to begin consuming 

adequate bait to induce mortality will be delayed. Rodents may also avoid established 

bait stations that have been disturbed by predators.

EPA Response: Based on data from the American Housing Survey (Census Bureau, 2011), over 

90 percent of rodent problems in residential units involve the house mouse, a species which has 

been reported to enter bait stations readily (e.g., Palmateer, 1982; Morris and Kaukeinen, 1988). 

Consequently, latency to enter bait stations is not expected to be a serious problem when house 

mice are being targeted. Commensal rats tend to be initially reluctant to enter bait stations newly 
Page 16 of 23

placed in their environment (e.g., Barnett, 1946), but they also tend to be reluctant to sample new 

potential food sources such as loose bait blocks and pelleted bait packets. Although there may be 

some delay and variation in the time for individual rats to find and consume new baits and 

succumb to their effects, the time-course for controlling infestations is likely to be similar once 

bait consumption begins, regardless of whether the bait is in a bait station or not.

10.4 SAP Comment (page 45): Limiting the bait formulation reduces the opportunity to 

select the formulation that is best suited for the environment in which control efforts 

are taking place. In some cases, pellets will have greater acceptance than a novel bait 

block. In some situations the bait blocks are more appropriate because of moisture or 

other factors.

EPA Response: Most residential consumers will be dealing with sporadic infestations (e.g., in 

the fall as rodents seeks shelter from colder weather). Even in cases of frequent infestations, the 

consumer will be facing new rodents each time. In such circumstances, where all elements of the 

rodents' environment are relatively new, bait stations are less likely to regarded as a new feature.

The bait-block formulations available for consumer use via the RMD have been demonstrated to 

be palatable and lethal to targeted rodents. 

Lublinkhof (2012) made the points that it is possible to produce bait blocks that are as well 

accepted as pellets (although in cage trials with laboratory strains) and that Bell’s trials with 

wild-type house mice with mouse-sized bait stations which contained bait blocks indicated entry 

by mice and 100% mortality in the test group. Lublinkhof (2011) also noted that bait blocks are 

not novel pest management tools and that they are the preferred bait form by professional 

applicators in residential settings. Kaukeinen and Marsh (2009) reviewed the approximately 50-

year history of rodenticide bait blocks in the U.S. and noted that improvements to formulation 

processes and bait palatability have occurred over that time period. Bait blocks have been on the 

residential consumer markets as far back as the late 1980s.

10.5 SAP Comment (page 45) EPA may have underestimated the complexity of effective 

rodent control in the home and assumed that a one-size fits all approach will provide 

homeowners with satisfactory results.

EPA Response: The RMD does not leave consumers with a “one-size fits all approach.” For the 

sometimes complex problem of controlling commensal rodents in the home environment, 

consumers have the options of a variety of rodenticide products – containing either firstgeneration anticoagulants or bromethalin, in a variety of distinct bait-block formulations, in 

tamper-resistant bait stations – and various types of traps, including glue and mechanical, 

covered or uncovered. It is important to note that snap traps are the only method of rodent 

control that the CDC recommends for consumers and that traps are generally less expensive than 

rodenticide baits. Furthermore, traps are currently the leading choice of consumers for 

controlling rodents, as shown by IRI sales register data (traps account for almost 70% of rodent 

control sales, whereas rodenticides account for about 30% of rodent control sales) (IRI data via 

Bell Laboratories, 2012). 
Page 17 of 23

10.6 SAP Comment (page 16 and 45): The requirement that rodenticides sold to 

residential consumers not contain the active ingredients brodifacoum, difethialone, 

bromadiolone, or difenacoum has the potential for increasing rodenticide resistance 

and limiting effective options. EPA has not adequately considered the risks and costs 

from increased rodenticide resistance and the potential costs associated with limiting 

chemicals that can be used in future products. 

EPA Response: EPA considered the risks of increased resistance to anticoagulant rodenticide 

products due to the proposed cancellation of SGARs and concluded that the risks are minimal. 

Resistance refers to genetic changes in a rodent population as a result of tolerant individuals 

being more likely to reproduce and pass that trait on to subsequent generations, as a result of 

rodenticides removing large portions of susceptible individuals. EPA recognizes that there is the 

potential for the development of resistance to anticoagulants given the way they work and the 

genetic and reproductive characteristics of rodents. However, residential consumer use of the 

conforming anticoagulant rodenticides will not be so widespread, frequent, and repetitive that 

enough anticoagulant tolerant individuals will be selected to result in a resistant population.

The Agency retains discretion to register new rodenticides if those registrations meet the 

standard of no unreasonable risk to human health or the environment, considering the risks and 

benefits of the rodenticides. Furthermore, in the event that a significant rodent resistance 

problem were to emerge, EPA retains the discretion to reconsider this cancellation, taking any

substantial new evidence into account.

Regarding SAP’s potential cost concerns, EPA acknowledges that there are likely local 

populations which include anticoagulant-resistant house mice and rats within the United States. 

However, the estimated incremental cost to residential users of cancelling SGARs is not based 

solely on their use of FGARs. As noted above, most of the currently available RMD-conforming

products found on retail store shelves contain bromethalin rather than FGARs. Resistance to 

bromethalin has not been reported. Therefore, the estimated cost is not affected by the presence 

of resistance to anticoagulants. 

11. Response to Comments within Charge Question 11:

11.1 SAP Comment (page 46): For the near term, the Panel believed effective control is 

possible with a combination of both an effective product and non-chemical methods. 

However, for the long term, limiting chemical control options to only two classes of 

rodenticides will likely lead to an increase in the number of commensal rodent 

populations that exhibit anticoagulant resistance and that will limit control options. 

The distribution of current anticoagulant resistant populations in the United States is 

not known.

EPA Response: The cancellation of particular pesticide products containing second-generation 

anticoagulants does not forever limit consumers’ chemical control options to only firstgeneration anticoagulants and acute rodenticides. The Agency retains discretion to register new 

rodenticides if that registration meets the standard of no unreasonable risk to human health or the 
Page 18 of 23

environment, considering the risks and benefits of the rodenticides. Furthermore, in the event 

that a significant rodenticide- resistance problem were to emerge, EPA retains the discretion to 

reconsider this cancellation, taking any substantial new evidence into account.

11.2 SAP Comment (page 46): The NOIC assumes that homeowners should rely more on 

non-chemical means of rodent control. The Panel is concerned that in the NOIC, EPA 

has failed to recognize the difficulty associated with non-chemical control, especially in 

those communities where rodent populations are at high levels. The complexity of the 

physical environment, coupled with food availability and the lack of what many would 

consider basic sanitation makes it impossible to effectively reduce harborage, eliminate 

food sources, manage adjacent land areas, limit access to buildings, or trap enough 

animals to impact the population. Dependence on non-chemical controls would be 

least effective for those neighborhoods that have the most significant problems. 

Further, many mechanical control products are not as effective as chemical 

rodenticides and mechanical tools are not subject to any efficacy requirements. 

EPA Response: EPA is not assuming that significant numbers of residential users of 

rodenticides will switch to non-chemical means of rodent control as a result of this action. To 

the contrary, EPA concludes that few residential users of rodenticides will switch to nonchemical controls as a result of this action. However, EPA is aware that a high proportion of 

general consumers already prefer non-chemical controls (70% per IRI 2012), and expects that a 

high proportion will continue to prefer such controls.

EPA has concluded that RMD-compliant rodenticides, considered as a whole, are likely to

perform as well as noncompliant rodenticides in the same situations, even where rodent control 

is challenging due to limitations to sanitation and rodent-proofing. See EPA’s Response to 

Comment 10.1.

In the case of house mice, EPA’s analysis and additional market data submitted after the SAP 

met show that RMD-compliant products are also approximately the same price as noncompliant 

products. Thus, EPA concludes that most residential users who would typically purchase a 

noncompliant rodenticide product for mouse control will simply purchase a compliant 

rodenticide and experience no difference in performance. 

In the case of commensal rats, EPA recognizes that currently available RMD-compliant 

rodenticides are more expensive than noncompliant products. Thus, some residential users who 

would typically purchase a noncompliant rodenticide may be prompted to shift to a lower-cost 

nonchemical control method such as snap traps. However, snap traps can effectively control 

rodents, including commensal rats, even where rodent populations are at high levels (Quy, et al., 

1995). In fact, because snap traps can be deployed with different food items or other attractive 

objects, they may be more effective than rodenticide baits in situations where other available 

food sources cannot be eliminated.

11.3 SAP Comment (page 46-7) The Panel concluded that the estimated added costs 

associated with the use of conforming rodenticide products along with non-chemical 

control are underestimated in the NOIC. ... [T]he costs of traps or rodenticides cannot 
Page 19 of 23

be considered on a ‘per infestation basis’ but have to be considered as an ongoing cost 

since individual efforts will seldom result in even localized elimination of rodents. This 

should be considered a social equity issue.

EPA Response: EPA disagrees that it has underestimated the added cost of using conforming 

rodenticide products instead of nonconforming products. The SAP conclusion is based on the 

Panel’s assumptions about potential reduced performance of conforming rodenticide products, 

which EPA has addressed in its previous responses above. EPA evaluated the incremental cost 

of switching from a non-compliant rodenticide product to a compliant rodenticide product or a 

non-chemical control method regardless of environmental conditions. Thus, EPA concludes that 

residential consumers will obtain similar levels of rodent control without expending additional 

efforts to improve sanitation or exclusion. 

Finally, regarding the unit of analysis, EPA disagrees that evaluating costs on a per-infestation is 

inappropriate. Even in communities where rodent populations are at high levels, the individual 

residential consumer may face repeated infestations but is likely to achieve the temporary 

elimination of rodents from his or her living unit. However, given local environmental 

conditions and access by rodents to the building, new rodents may soon enter the household 

space. It is precisely for that reason that EPA placed the increase in costs in the context of the 

monthly income of a household at the poverty level. 

11.4 SAP Comment (page 47): Noncompliance with product labeling is likely . . . and 

inappropriate use will continue, even with RMD compliant products.

EPA Response: EPA recognizes that it is likely that there will be some degree of inappropriate 

use of any pesticide product that is widely marketed to consumers. However, this truism does not 

undermine EPA’s conclusion that the RMD-conforming rodenticide products dramatically 

improve consumers’ capability to comply with label requirements regarding placement where 

children, pets, or non-target wildlife might have access. Nor does it establish that cancellation of 

the rodenticide products subject to the NOIC (which do not at all augment consumers’ capability 

to make compliant placements) is futile. Prior to the issuance of the RMD and the subsequent 

registrations of RMD-conforming consumer-oriented products, it was difficult for residential 

consumers to locate and purchase the tamper-resistant bait stations that they were directed to use 

when bait placements otherwise would have been within reach of children under six years-ofage, pets, domestic animals, and/or non-target wildlife. The registrants who have introduced 

products that conform to the RMD have provided such persons with bait products that include 

protective bait stations, thereby, for the first time, making appropriate use of bait in accessible 

areas a realistic possibility for residential consumers.

12. Response to Additional Panel Comments:

12.1 SAP Comment (page 50): Under “Pest Resistance and Use of FGARs” The role of 

increased pest resistance from use of FGARs was not addressed in the background 

document. ... If increased usage of an FGAR alternative leads to development of 
Page 20 of 23

widespread pest resistance, ... there appears to be a potential risk of needing to reintroduce SGARs, or other alternative products, back into the domestic market in 10 years 

or so. 

EPA Response: EPA recognizes the general potential for a currently unreasonable risk to 

become a reasonable risk at some later date, due to a potential future relative increase in benefits. 

But specifically with respect to the possibility that consumer use of non-conforming rodenticide 

products might become necessary in ten years’ time, EPA does not agree that this potential is a 

reasonable basis to forego action to eliminate currently unacceptable risks. Regarding resistance 

more generally, see EPA’s response to SAP Comment 10.6. 

12.2 SAP Comment (page 50-51) Under “Rodenticide Use Awareness Programs”, the 

SAP recommends that: “More proactive training and education as currently being carried 

out in the United Kingdom and Europe should also be considered. Helping homeowners 

more easily understand how their actions impact children, pets, and wildlife has the 

potential of reducing the off label uses that increase risk for non-target impacts. It would 

be worth taking a closer look at the Campaign for Responsible Rodenticide Use to 

understand how that has impacted use of rodenticides in the United Kingdom. If there is 

evidence that programs such as the Campaign for Responsible Rodenticide Use can 

reduce non-target impacts there may be value in considering a similar program in the 

United States.”

EPA Response: EPA agrees that proactive training and education are important and should be 

encouraged. According to their website, The Campaign for Responsible Rodenticide Use appears to be 

an organization that promotes responsible rodenticide bait use among professional applicators and 

agricultural professionals in the United Kingdom. Based on the website, it is not clear that this 

organization has any outreach to “homeowners” although it would be possible for residential consumers 

to access the website and read the materials.

In the U.S., EPA has conducted outreach and published educational materials through its Field 

and External Affairs Division (FEAD) aimed at the residential consumer who is attempting to 

control household pests. In addition, the CDC has published manuals on commensal rodent 

control for about 60 years. Various other agencies and non-governmental organizations also have 

developed and circulated relevant educational materials, sometimes as part of specific campaigns 

to control one or more species of commensal rodents. Still, misuse, rodenticide exposure 

incidents, and rodent control problems persist. While public educational efforts are useful and 

should be encouraged, it is clear that those efforts alone are insufficient to solve the exposure and 

risk issues that are addressed with the RMD.
Page 21 of 23

Literature Cited:

Ashton, A.D., W.B. Jackson and H. Peters. 1986. Comparative evaluation of LD50 values for 

various anticoagulant rodenticides in Control of Mammal Pests (eds. C.G.J. Richards and 

T.Y. Ku) Tropical Pest Management 32 (supplement) 1: 187-197.

Barnett, S.A. 1946. Infestation Control: Rats and Mice. London: His Majesty’s Stationery Office, 

36 pp.

Buchanan, S. 2007. Re: Proposed Risk Mitigation Decision for Nine Rodenticides, Docket ID 

number EPA-HQ-OPP-2006-0955, Letter of May 17 to Office of Pesticide Programs, U.S. 

Environmental Protection Agency. Division of Emergency and Environmental Services, 

National Center for Environmental Health Services, Centers for Disease Control and 

Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, 

GA. 2 pp.

Buchanan, S.D. 2012. Re: Draft Notice of Intent to Cancel and Notice of Denial of Registration 

for Certain Rodenticide Products, Letter of April 20 to Office of Pesticide Programs, U.S. 

Environmental Protection Agency. Division of Emergency and Environmental Services, 

National Center for Environmental Health Services, Centers for Disease Control and 

Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, 

GA. 1 p. plus attachments.

Buckle, A.P. and Prescott, C.V. 2011. Effects of tamper-resistant bait boxes on bait uptake by 

Norway rats (Rattus norvegicus Berk.). Journal of Pest Management 57:1, 77-83.

Caravati, E.M, A Erdman, E Scharman, A Woolf, P Chyka, D Cobaugh, P Wax, A Manoguerra, 

G Christianson, L Nelson, K Olson, L Booze, and W Troutman. (2007) Long-acting 

anticoagulant rodenticide poisoning: An evidence-based consensus guideline for out-ofhospital management. Clinical Toxicology (2007) 45, 1–22.

Census Bureau. 2011. American Housing Survey (AHS) for the United States: 2009. U.S. 

Census Bureau, U.S. Dept. of Commerce. Series H-150/05. Available at: 

http://www.census.gov/prod/2011pubs/h150-09.pdf.

Fisher, P., E.B. Spurr, S.C. Ogilvie, and C.T. Eason. 2007. Bait consumption and residual 

concentrations of diphacinone in the Wellington tree weta (Hemideina crassidens) 

(Orthoptera: Anostostomatidae). New Zealand Journal of Ecology 31(1): 104–110

Hindmarch S, Elliott JE. (2011a). Investigating the potential risk of secondary rodenticide 

poisoning to owls inhabiting and foraging in urban landscapes of the Lower Mainland, 

British Columbia. Raptor Research Foundation Annual Meeting, Oct 5 – 8, 2011, Duluth 

MN.
Page 22 of 23

Hindmarch S, Elliott JE. (2011b). Investigating the potential risk of secondary rodenticides 

poisoning to owls inhabiting and foraging in urban landscapes of the Lower Mainland, 

British Columbia. Draft Report to the Pesticide Science Fund, Environment Canada, Delta, 

BC.

IRI. 2012a. Mouse Bait Sales. Symphony IRI Group, latest 52 weeks ending 7/8/2012. 

Submitted by Steve Levy, Bell Labs, email to Neil Anderson, 07/27/2012.

IRI. 2012b. Rodent Control Unit Sales. Symphony IRI Group, latest 52 weeks ending 

7/8/2012. Submitted by Steve Levy, Bell Labs, email to Neil Anderson, 07/27/2012.

Kaukeinen, D. and Marsh, R.E. 2009. Paraffinized rodenticide: here to stay. Pest Management 

Professional, March 2009, 53-54, 56, 58, 60. (Accessed from www.mypmp.net)

Lublinkhof, J. 2012. Comments on SAP meeting minutes. Letter of March 1, 2012, to Richard 

Keigwin, Director of Pesticide Re-Evaluation Division, EPA/OPP/OCSPP. Bell 

Laboratories, Inc., Madison, WI, 6 pp.

Lublinkhof, J. 2011. Comments to docket EPA-HQ-OPP-2011-0718; FIFR Scientific Advisory 

Panel; Notice of Public Meeting. Federal Register Vol. 76, No. 173, Wed. Sept. 7, 2011, 

Pages 55381-55384. Letter of November 15, 2011, to Richard Keigwin, Director of 

Pesticide Re-Evaluation Division, EPA/OPP/OCSPP. Bell Laboratories, Inc., Madison, WI, 

5 pp.

Morris, K.D. and Kaukeinen, D.E. 1988. Comparative evaluation of tamper-proof mouse bait 

stations. Proceedings: 13th Vertebrate Pest Conference, A.C. Crabb and R.E. Marsh (eds.), 

University of California, Davis, CA, 13: 101-106.

Palmateer, S.D. 1982. Tamperproof bait boxes. Unpublished report, Terrestrial and Aquatic 

Biology Unit, Office of Pesticide Programs, U.S. Environmental Protection Agency, 

Beltsville, MD, 46 pp.

Pitt, W. C., Driscoll, L.C., and Sugihara, R.T. 2011. Efficacy of rodenticide baits for the control 

of three invasive rodent species in Hawaii. Arch. Environ. Contam. Toxicol. 60, 533-542.

Quy, R.J., Cowan, D.P., Morgan, C., and Swinney, T. 1996. Palatability of rodenticide baits in 

relation to their effectiveness against farm populations of the Norway rat. In: Proc. 17th

Vertebrate Pest Conf. (R.M. Timm and A.C. Crabb, eds.), University of California, Davis, 

CA, 17: 133-138.

Shirazi MA. Bennett US, Ringer RK. 1994. An interpretation of toxicity response of bobwhite 

quail with respect to duration of exposure. Archives of Environmental Contamination and 

Toxicology 26:417-424.

USEPA. 2011. Risks of Non-Compliant Rodenticides to Nontarget Wildlife, Background Paper

for the Science Advisory Panel on Notice of Intent to Cancel Non-RMD Compliant 
Page 23 of 23

Rodenticide Products. United States Environmental Protection Agency, Office of Chemical 

Safety and Pollution Prevention, Office of Pesticides Programs, Environmental Fate and 

Effects Division.

Witmer, G.W. 2007a. Efficacy of commercially available rodenticide baits for the control of wild 

house mice. Final Report, QA-1304, National Wildlife Research Center, USDA/APHIS 

Wildlife Services, Fort Collins, CO, 16 pp. 

Witmer, G.W. 2007b. Efficacy of commercially-available rodenticide baits for the control of 

introduced Norway rats. Final Report, QA-1232, National Wildlife Research Center, 

USDA/APHIS Wildlife Services, Fort Collins, CO, 12 pp.