Charge Questions
SAP on Rodenticide NOIC

– Nov. 29

– Dec. 1, 2011

Page 1 of 5 EPA’s draft Notice of Intent to Cancel (NOIC) proposes to cancel 20 rodenticide products and EPA’s draft Notice of Denial proposes to deny 4 rodenticide products. The products are all subject to this action because they cause unreasonable risk to humans, pets, and/or non

- target wildlife when used by residential consumers. In the 2008 Risk Mitigation Decision for Ten Rodenticides (RMD), EPA determined that the unreasonable risks owing to primary exposure of children, pets, and non

- target wildlife could be mitigated through the use of tamper

- resistant bait stations reasonably expected to not release rodenticide bait except for bait removed by target rodents and minor quantities of crumbs created by target rodent , and the unreasonable risks owing to secondary exposure of non

- target wildlife could be mitigated through the elimination of the active ingredients brodifacoum, difethialone, bromadiolone, or difenacoum

. 1 All references to “conforming” or “non

- conforming” in these charge questions refer to whether a product conforms to these two risk mitigation measures as described in the RMD . P lease consider whether the data currently available adequately supports the Agency’s analyses
and conclusions.

Risks to Humans

1. Does the Agency’s analysis of the mammalian tox icity studies and human incident reports provide a reasonable basis for concluding that exposure to warfarin, brodifacoum, difethialone and/or bromethalin can cause health effects in individuals who ingest these rodenticides? Are the adverse effects descr ibed in the children’s incident reports [ e.g., anemia, melena (bloody stool), hematemesis (vomiting of blood) ], credible consequences of exposure to these active ingredients ? Please provide the basis for your conclusions.

2. The human incident report summar izes a number of data and information sources used in the analyses and reviews conducted. Based on the incident report analysis, EPA has concluded that there are a large number of rodenticide exposure incidents that involve children less than 6 years old . While exposure generally results in no clinical harm to children, the exposures to rodenticides have the potential to result in severe outcomes and/or require medical care or follow

- up. Does the SAP concur with the EPA’s conclusions regarding the exten t of exposures, potential severity of effects, and degree of risks posed to humans? Are the conclusions reached reasonably supported by the data analysis? Please explain the basis of your position

.

3. Based on t he human incident report

, EPA concludes that the use of conforming rodenticide products will reduce the risk rodenticides pose to humans by reducing the opportunity for exposure. Is it reasonable to expect that limiting consumer use to conforming rodenticide products will generally r educe the opportunity for exposure of humans to commensal rodenticide products? Please provide the basis for your
conclusions.

1 The RMD also included other risk mitigation measures not at issue here.Charge Questions
SAP on Rodenticide NOIC

– Nov. 29

– Dec. 1, 2011

Page 2 of 5 Risks to Pets

4. The pet incident report summarizes a number of data and information sources used in the analyses and reviews c onducted. The EPA concludes that there is a high frequency of reported pet incidents involving rodenticides, many of which result in severe outcomes; this conclusion is further supported by the information reported in the open literature as well as the ch aracterization of primary acute risk. Does the SAP concur with EPA’s conclusions of the risks posed to pets by non

- conforming rodenticide products? Are the conclusions reached reasonably supported by the data analysis? Please explain the basis of your pos ition.

5. The pet analysis has relied on the assessment of risks to wildlife from primary

exposure as one line of evidence to characterize primary acute risk to pets from non

conforming rodenticide products. Is it reasonable to conclude that risks to pets a re similar to risks to non

- target mammalian wildlife, assuming comparable exposures ? Please explain the basis of your conclusions.

6. Based on t he pet incident report

, EPA concludes that the use of conforming rodenticide products will reduce the opportunity for exposure of pets to rodenticides. Is it reasonable to expect that limiting consumer use to conforming rodenticide products will generally reduce the opportunity for exposure of pets to commensal rodenticide products? Please provide the basis for your conclusions.

Risks to Wildli f e

7. The EPA has conducted a deterministic risk assessment to evaluate the risks of acute toxicity to non

- target mammals and birds from primary exposure to non

- conforming rodenticide products . In its assessment , EPA calculated risk quotients on an acute oral dose and acute dietary exposure basis for birds and mammals and further characterized the opportunity for exposure at lethal levels based on factors including the number of days required to feed and the mass of pesticide required to be consumed to reach lethal thresholds. Using the best available data, EPA made assumptions relative to toxicity, accumulation, and clearance of the pesti cides that are material to the exposure and effects modeling in the deterministic primary risk

assessment.

a. Please comment on the reasonableness of the following aspects of EPA’s primary exposure deterministic risk assessment:

• Selection of toxicity en dpoints for species common to all assessed chemicals in light of the incomplete overlap across available data sets;

• The use of allometric toxicity scaling approaches for birds;Charge Questions
SAP on Rodenticide NOIC

– Nov. 29

– Dec. 1, 2011

Page 3 of 5 • The reliance on mammalian first order liver or plasma elimination half
lives to estimate whole body wildlife (birds and mammals) elimination rates for anticoagulants and bromethalin, respectively;

• The use of the time required and the consumption of rodenticide mass required to reach lethal thresholds as a means of comparing the rel ative risks of acute mortality following consumption of rodenticide bait;

b. In addition, does the P anel concur with EPA’s analysis and conclusion that use of

non

- conforming rodenticide products (i.e., not in bait stations) can cause adverse
effects to non

- target wildlife? Please provide a basis for your conclusions.

c. Is it reasonable to expect that placing rodenticide products in tamper resistant bait stations with formulations expected to remain in the bait station will generally
reduce the opportunity for primary exposure of wildlife to commensal rodent control products? Please provide a basis for your conclusions.

8. The EPA has conducted a deterministic risk assessment to evaluate risks of acute toxicity to non

- target mammals and birds from secondary exposure to non

conforming rodenticide products. In its exposure estimate, EPA used both calculated
theoretical contam ination levels in prey and available empirical data. EPA also characterized the secondary exposure risk using secondary feeding studies and factors including the number of contaminated animals required to be consumed to reach lethal exposure thresholds. For these analyses, using the best available data, EPA made assumptions relative to toxicity, accumulation, and clearance of the pesticide that are material to the exposure and effects modeling in the deterministic secondary

exposure risk assessment.

a. Pl ease comment on the reasonableness of the following aspects of EPA’s secondary exposure deterministic risk assessment:

• The use of theoretical body burden calculation together with empirical whole body residue data to produce a reasonable range of estima ted exposures for secondary exposure pathways;

• The use of the number of prey items required to reach lethal thresholds as a means of comparing the relative risks across the assessed rodenticides of acute mortality following consumption of contaminated pre y;

• The conclusion that the results of predator / scavenger feeding studies are consistent with the findings of the deterministic secondary risk

assessment;

• The use of a standardized set of avian toxicity endpoints (i.e., species
tested across all the as sessed chemicals) in light of information on diphacinone suggesting that raptors may be more sensitive than the surrogate avian species used in the risk assessment.

b. Does the P anel concur with EPA’s analysis and conclusion that consumption of living or dead rodents poisoned by brodifacoum or difethialone presents a greaterCharge Questions
SAP on Rodenticide NOIC

– Nov. 29

– Dec. 1, 2011

Page 4 of 5 opportunity for adverse effects to non

- target wildlife compared with the rodenticides warfarin, diphacinone , chlorophacinone, or bromethalin? Please provide a basis for your conclusions. Does the P anel concur that cancellation of products containing brodifacoum and difethialone sold to residential consumers
will reduce the opportunity for secondary exposure for wildlife to rodenticides?

P lease provide a basis for your conclusions.

9. Incident data demonstrate that rodenticide use can result in wildlife mortality, and
that such wildlife mortalities occur in urban and suburban areas. Based on this incident data, EPA has concluded that consumer use of rodenticides in urban and
suburban a reas may be a significant contributor to the wildlife mortalities attributable to rodenticides. The EPA also determined that both primary and secondary poisonings have been documented.

a. As part of its analysis of incidents, EPA analyzed the available in cident data in order to associate incidents with specific land use categories, i.e., agricultural, urban, suburban areas. In performing this analysis, EPA relied on the information in incident reports identifying associated habitat or on the address repor ted for the incident and then used remote sensing information to assign a land use category with the incident. Please comment on the reasonableness of this approach to using location information to support the conclusion that use of the commensal
rodentic ides addressed in the draft NOIC causes wildlife mortalities in urban and
suburban areas , as well as rural areas

.

b. EPA analyzed the available incident data in order to differentiate primary and secondary wildlife mortality. For this analysis, EPA relied on information on the dietary requirements of the moribund species and any identified gut contents when available. Does the Panel find this approach a reasonable way to evaluate the occurrence of primary and secondary toxicity as causes of wildlife morta lity? Please provide the basis for your conclusions.

Efficacy of Conforming Rodenticide Products

10. EPA requires registrants of commensal rodent control products to demonstrate that their products meet criteria for efficacy

. The registrants of conforming rodenticide products have submitted such data to EPA

, and EPA has determined that their products meet these criteria

. Do the meeting of these efficacy performance criteria and EPA’s analysis of the effectiveness of conforming rodenticide products
reasonab ly support conclusions that conforming rodenticide products provide
effective options for chemical control of commensal rodents by nonprofessional

users? If you conclude that conforming rodenticide products do not provide effective options for chemical co ntrol of commensal rodents by nonprofessional users, p lease discuss to what extent the following requirements affect the availability to consumers of effective options for control of commensal rodents:Charge Questions
SAP on Rodenticide NOIC

– Nov. 29

– Dec. 1, 2011

Page 5 of 5 • The requirement that rodenticides sold to residential consumers must include
tamper

- resistant bait stations;

• The requirement that rodenticides sold to residential consumers must be in
forms (e.g. bait blocks) which are reasonably expected to remain within the bait station; and

• The requirement that rodentic ides sold to residential consumers not contain the active ingredients brodifacoum, difethialone, bromadiolone, or difenacoum

.

Please provide the basis for your conclusions.

11. Are conforming rodenticide product s containing the active ingredients warfarin, diphacinone, chlorophacinone, or bromethalin

, along with non

- chemical rodent
control methods available to consumers and other options

, capable of providing
effective control of commensal rodents ? Please provide the basis for your
conclusions.