2 Rodenticide Active Ingredients

There are a number of substances that are registered or were previously registered as vertebrate control agents. Phosphorus and arsenic trioxide were once re gistered to control commensal rodents in and around homes, but the Agency has cancelled all such products. Strychnine is no longer registered for control of commensal rodents and for this reason it has typically been evaluated separately from rodenticide active ingredients that are registered for control of commens al rodents. Substances su ch as red squill and pival (and its sodium salts), historically used to c ontrol commensal rodents, were not supported for reregistration by their registrants. As there we re no remaining registered products for them, these chemicals were not evaluated in the 1998 Rodenticide Cluster RED or thereafter. This regulatory history document addresses the ten rodenticide active ingredients that remain registered for control of commensal rodents and they include the following:

1 st Generation Anticoagulants

The first generation anticoagulant rodenticides (F GARs), such as chlorophacinone, diphacinone, diphacinone sodium salt, warfarin, a nd warfarin sodium salt, disrupt the production in the liver of vitamin K dependent blood-clotting factors II (prothrombin ), VII, IX, and X. Due to the long half-lives of the vitamin K-dependent clotting factors, the anticoa gulant effect often does not adversely affect the rodent until after several days of ingestion The onset of lengthened prothrombin time (PT) from a toxic dose may occur within 24 hours, and reach a maximu m in 36-72 hours at a dose much lower than the dose that can cause hemorrhage (Reigart J.R. et.al, 1999) . The agents also incr ease permeability of capillaries throughout the body, leading to widespread internal hemorrhage.

 warfarin (and its sodium salt) (PC Code 086002, CA S No. 81-81-2) (sodium salt PC Code 086003 129-06-6)

o 1950 - First Registered

o 1954 - Sodium Salt First Registered

o 1981 - Registration Standard

o 1991 - Warfarin and it Sodium Salts RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

 diphacinone (and its sodium salt) (PC Code 067701, CAS No. 82-66-6) (sodium salt PC Code 067705 42721-99-3)

o 1960 - First Registered

o 1962 - Sodium Salt First Registered

o 1998 - Included in Rodenticide Cluster RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

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 chlorophacinone (PC Code 067707, CAS No. 3691-35-8)

o 1971 - First Registered

o 1998 - Included in Rodenticide Cluster Reregistration Eligibility Decision (RED)3 o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

2 nd Generation Anticoagulants (Also Referred to as Long Acting Anticoagulant Rodenticides (LAARs) or “Super Warfarins”)

The second generation anticoagulant rodenticides (SGARs) such as brodifacoum, bromadiolone, difenacoum, and difethialone are more acutely toxi c than are FGARs and were developed to control commensal rodents that are resistant to warfarin a nd other FGARs. SGARs also are more likely than FGARs to be lethal effects to rodents as a consequen ce of one night’s feeding in a single dose. Like the FGARs, SGARs block the formation of the active form of vitamin K, which in turn inhibits the production of coagulation factors in the liver. These ch emicals block the same binding site that warfarin and warfarin sodium block, however, SGARs have much longer half-lives in the body (Batten and Bratt, 1990). Similar to the first generation anticoagulants, the toxic effects of SGARs usually begin several days after ingestion, because of the long half-life of the coagulation factors.

 brodifacoum (PC Code 112701, CAS No. 56073-10-0)

o 1979 - First Registered

o 1998 - Included in Rodenticides Cluster RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

 bromadiolone (PC Code 112001, CAS No. 28772-56-7)

o 1980 - First Registered

o 1998 - Included in Rodenticides Cluster RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

 difethialone (PC Code 128967, CAS No. 104653-34-1)

o 1995 - First Registered

o 1998 - Addressed by but not assessed in Rodenticides Cluster RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

 difenacoum (PC Code 119901, CAS No. 56073-07-5)

o 2007 - First Registered

o 2008 - Included in the RMD

Non-Anticoagulants (Also Referred to as Acute Rodenticides)

Bromethalin, causes decreased production of ATP in the cells of the central nervous system by uncoupling oxidative phosphorylation in the mitochondria . Low levels of ATP reduce the efficiency of the enzyme Na/K ATPase, leading to increased intracellu lar sodium levels. This in turn draws more water into neuronal cells (cerebral edema) and increases intr acranial pressure which can be lethal. Symptoms4 and signs of cerebral edema include headache, dizziness, nausea, numbness, weakness, loss of coordination or balance, altered le vel of consciousness, respiratory depression, seizures, and death.

Cholecalciferol increases calcium absorption from food, and mobilizes calcium from bone which leads to hypercalcemia (increased calcium levels in blood). Hypercalcemia can cause formation of calcium crystals in internal organs such as blood vessels, kidneys, stomach wall and lungs (Chavhan S.G., et.al, 2011). Abnormal heart conduction and irregular hear tbeats can also occur si nce the heart tissue is sensitive to changes in blood calcium levels. Sy mptoms and signs of cholecalciferol poisoning may include fatigue, weakness, nausea, anorexia, headach e and irregular heartbeats (Goldfrank et.al, 2010). Acute renal tubular injury due to hypercalcemia ma y cause excessive urination, increased water intake, protein in urine and increased blood urea levels. Prolonged hypercalcemia may eventually cause kidney failure due to formation of kidney stones and calcium deposition in kidney tissues.

Zinc phosphide can quickly produce toxic phosphine gas when it comes in contact with acids or water. Phosphine is thought to produce toxicity by blocking cytochrome oxidase and, inhibiting oxidative phosphorylation which may lead to cell death (Perry H. E., 1998). Most of the tissue damage can occur in liver, kidneys and heart. Patients may present with sy mptoms such as, severe gastrointestinal irritation, nausea, vomiting (with fishy odor), chills, tightness of chest, difficulty in breathing and cough (from pulmonary edema). Development of the liver fa ilure can cause jaundice and excessive hemorrhage. Delirium, convulsions and coma may result from renal tubular damage. Common cause of death is from ventricular arrhythmias and shock due to myocardial damage (Reigart J.R., 1999).

 zinc phosphide (PC Code 088601, CAS No. 1314-84-7)

o 1947 - First Registered

o 1982 - Registration Standard

o 1998 - Zinc Phosphide RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

 bromethalin (PC Code 112802, CAS No. 63333-35-7)

o 1984 - First Registered

o 1998 - Included in Rodenticides Cluster RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD

 cholecalciferol (PC Code 202901, CAS No. 67-97-0)

o 1984 - First Registered

o 1998 - Addressed by but not assessed in Rodenticides Cluster RED

o 2004 - Included in Potential Risks of Nine R odenticides to Birds, and Nontarget Mammals: A Comparative Approach

o 2008 - Included in RMD5 Additional Background

Pests Targeted by Rodenticides

The three commensal rodent species th at occur in the continental U.S., are the Norway (brown or sewer) rat ( Rattus norvegicus ), the roof (black or ship) rat ( Rattus rattus ), and the house mouse ( Mus musculus ). These species are of Asian origin and were brought to the Western Hemisphere, probably inadvertently, via the activities of humans. The Polynesian (Pacific, kiore) rat ( Rattus exulans ) occurs in forests, fields, and commensally in Hawaii and in various U.S. isla nd territories in the Pacific Ocean. Rodenticides are also registered for use against other vertebrate pest s including, but not limited to voles, deer mice, whitefooted mice, wood rats, kangaroo rats, pocket gop hers, prairie dogs, ground squirrels, and some nonrodents (e.g., moles); however, only products intended for the control of commensal r odents are the focus of the Agency’s current action

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Uses of Rodenticide Bait Products

Rodenticide baits, along with a variety of habitat modi fication and other pest management techniques, are used to reduce the damage caused by rodents. Rodent icide baits are especially useful for rapidly reducing rodent numbers in cases of major infestations. For comm ensal rodent control, rodenticide baits are best used within the context of an inte grated pest management (IPM) approach that emphasizes measures such as sanitation, exclusion, habitat modification, trapping, coordination at the community level, public health education, and legal measures such as the enforcement of sanitation codes.

Rodenticide baits are used, sometimes as part of co mmunity rodent-control programs, in situations where major commensal rodent infestations must be reduced rapidly. The baits often are used to control rodents which have entered homes and other bu ildings. They are also used to e liminate rodents that remain after buildings have been rodent-proofed. Rodenticide ba its are commonly used to manage both indigenous and introduced rodents that feed on, contaminate, or cause various types of damage to a wide range of crops and farm infrastructure and equipment, as well as to grain and other stored food.

Registered Use Site Categories for Rodenticides Buildings and Transport Vehicles

Prior to the 2008 RMD, the Agency typically allowe d the following sites for commensal rodenticides: in and around homes and residential buildings, industri al, commercial, agricultural buildings, and similar man-made structures and in transport vehicles. Fo r some products, the Agency allowed additional field sites (fence lines, gullies, ditches, railroad rights-of way, garbage dumps). For zinc phosphide products, the Agency classified products with such field sites as “Restricted Use Pesticides” over 30 years ago. For products subject to the 1998 Rodenticide Cluster RE D, the Agency required that products with field sites be classified “restricted use,” except for hand, underg round applications for control of mole and pocket gophers. The RMD implemented this requireme nt of the 1998 Rodenticide Cluster RED.

 Agricultural Uses –Prior to the 2008 RMD, rodentic ide products that were distinctly for use in agricultural settings were not common. Agricultural buildings use site restrictions were typically limited to inside of homes and agricultural buildi ngs in “non-urban” areas (i.e. rural and suburban6 areas). The urban vs. non-urban use site distincti on has been replaced with labeling that permits use in and within 50 feet of agricultural building.

 Homeowner Uses – Prior to the 2008 RMD, rodenticid e products that were distinctly for use in homes were available, but many registered commens al rodenticide bait products were available in container sizes ranging from less than one pound to more than 40 pounds and were labeled for industrial and agricultural use sites in addition to use in and around residences. In an effort to mitigate risk, the 2008 RMD identified certain risk mitigation measures that the Agency intended to require of all rodenticide products sold a nd marketed to residential consumers.

 Pest Control Operator (PCO) Uses - Prior to the 2008 RMD, the only rodenticide products that were distinctly for PCO use were those classified as “r estricted use.” Labels for bromadiolone and difethialone products distinguished between “urban” and “non-urban” use sites. In “Urban Areas” the labeled use sites were in and around homes, i ndustrial buildings, commercial buildings, public buildings, transport vehicles (ships, trains, aircraft), related port or terminal buildings, and in alleys. In “Non-Urban Areas” labeled use sites included insi de of homes and agricultural buildings. In an effort to mitigate risk, the 2008 RMD announced that EPA wo uld require certain limitatio ns on sale and distribution designed t o further distinguish rodentici de products sold and marketed to residential consumers from produ cts intended for commercial, ag ricultural, and other professional users.  This has al so led to the registration of r odenticide products that are distinctly labeled for use by PCOs only.

Field

 Field-use rodenticides are rodenticide products labe led for use to control rodents and lagomorphs in orchards; rangelands; field crops; non-crop areas, including but not limited to fence lines, gullies, ditches, orchards, railroad rights-of way, garb age dumps, landfills, and sites not associated with human residences or other buildings. Most field-u se rodenticides are registered as restricted use products (RUP) and require a Certified Applicator license or be under the direct supervision of a certified applicator to purchase and apply.

Efficacy Requirements For Rodenticide Products

As a general matter, in order to obtain or maintain a registration for a pesticide under FIFRA, an applicant or registrant must demonstrate that the pesticide sa tisfies the statutory standard for registration. Section 3(c)(5) of FIFRA. 7 U.S.C. 136a(c)(5). That standa rd requires, among other things, that the pesticide performs its intended function withou t causing “unreasonable adverse effects on the environment.” The term “unreasonable adverse effects on the envir onment” is defined under FIFRA section 2(bb) as “any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits of the use of any pesticide.” 7 U.S.C. 136(bb).

In addition to the standard registration criteria th at all registered pesticides must meet, because commensal rodents are pests of public health signifi cance, commensal rodenticide products are required to meet the efficacy testing requirements that EPA h as established for registration of such products under FIFRA. In order to demonstrate the effectiven ess of a new rodenticide active ingredient or new formulation of an existing active ingredient for c ontrolling commensal rodents, EPA requires (1) acute oral toxicity testing with wild-type animals of th e targeted species; (2) laboratory efficacy screening of7 one or more bait formulations with wild-type animals of the targeted species; (3) indoor and outdoor field efficacy trials involving the targeted species in act ual use situations in different regions of the U.S. 1 These tests are not designed to rank the efficacy of the various rodenticide products, but instead to establish whether each product meets the registration criteria in regards to the products ability to effectively control commensal rodent species.

For additional information on the efficacy requireme nts for rodenticide products labeled for use on commensal rodent pests, see the paper entitled Efficacy Issues Regarding Control of Commensal Rodents in the U.S. Using Registered Rodenticides (W. Jacobs, 10/31/2011) in docket ID EPA-HQ-OPP-2011- 0718.

Regulatory History

Pre-1998

Rodenticide products containing any of a variety of different active ingredients have been Federally registered under the FIFRA according to the requireme nts that were in effect at the times that the compounds were registered. Requirements for labeli ng and data support change d over time, with data requirements being intensified by certain amendments to FIFRA.

The 1972 amendments to FIFRA included the requirement that EPA bring pesticides registered prior to the passage of those amendments up to the new standa rds for registering new pesticides. This process became known as “Reregistration.” In its first e fforts to reregister pesticides, EPA would produce Registration Standard documents that summarized then -existing circumstances regarding product labeling and data support and identi fied deficiencies in both areas that regist rants were required to support in order to reregister their products. EPA then issued da ta call-ins (DCIs) which required submission of the studies needed to address the “data gaps” noted in Registration Standard documents. Registrants were required to provide the missing data if they wanted to retain their products’ registrations.

During the 1980’s, EPA issued Registration Standard s for Warfarin and Zinc Phosphide but not for the other then-registered rodenticide chemicals that later were considered in the RMD. EPA also issued a Registration Standard for the “first-generation” anticoagulant Fumarin, but all of its products subsequently were canceled because their registrants did not support them for reregistration. Although these Registration Standards represented EPA’s determ inations of what data submissions and label changes were necessary to support registration, they did not have the force of law.

The 1988 amendments to FIFRA added to the Act a new Section 4 which outlined a five-phase process for reregistration of pesticide chemicals and products for which the first Federal registration had been issued prior to November 1, 1984. As required by the amendments, EPA prepared four lists of active ingredients for which reregistration was required. List A included active ingredients (such as warfarin and zinc phosphide) for which EPA previously had issu ed Registration Standards. Lists B, C, and D included the pesticides registered prior to November 1, 1984, for which no Registration Standard had been issued. Lists B, C, and D were to be popul ated by active ingredient s according to priority, as

1 General guidance for the design of such studies appears on pages 307-310 of Subdivision G of EPA’s Pesticide Assessment Guidelines, Office of Pesticides and Toxic Substances, Washington, DC, 1982.8 described in Section 4(c)(1) of FIFRA as ame nded in 1988. The anticoagulants brodifacoum, bromadiolone, chlorophacinone, diphacinone, pindone (piv al), and valone (PMP) were placed on List B, which was to have the highest priority among Lists B, C, and D. The nerve toxicant, bromethalin was also placed on List B.

The 1988 FIFRA amendments required up-front comm itments to the reregistration process by the registrants of the active ingredients. Registrants were required to indicate which active ingredients and which uses of them they intended to support thro ughout the entire reregistration process. Unsupported chemicals and use patterns were to be dropped. Valo ne and pindone ultimately were not supported. The chemicals that were to be supported went through re maining phases of data submission, data evaluation, risk assessment, and risk management which led to the production of reregistration eligibility decisions for each active ingredient or each grouping of active i ngredients (according to related chemistry and/or similarity in primary use patterns). Data needed to complete product reregist rations were required via product-specific data call-ins (PDCI’s).

In June 1991, EPA completed a RED for warfarin and its sodium salt which calle d in additional data and identified the following mitigation measures as necessa ry in order for products to be eligible for reregistration:

 Continued RUP classification of tracking powder products.

 A statement regarding teratogenicity, warning of warfarin's potential to cause birth defects, was required for tracking powder products and c oncentrates used to prepare dry baits.

 To prevent contamination of food and feed, tracking powder products intended for use in food/feed handling establishments were to lim it placement of powder to concealed, inaccessible places.

 To protect children and non-target animals, track ing powder products were required to bear a strong precautionary statement and new restrictions limiting placement of powder to locations not accessible to children, pets, domestic animals or non-target wildlife.

 To protect children and non-target animals, bait prod uct labels were to require the use of tamperresistant bait stations wherever bait placements ot herwise would be within the reach of children, pets, domestic animals, or nontarget wildlife.

The bait-protection text prescribed via the Warfarin RE D was similar to that later included in Pesticide Registration Notice (PR Notice) 94-7, which is discussed in more detail later in this document.

REDs for zinc phosphide and the Rodenticide Cl uster were published in 1998, and these addressed reregistration eligibility and labeling requirements for end-use products containing brodifacoum, bromadiolone, bromethalin, chlorophacinone, and diphacinone. The provisions of these REDs are discussed in detail below. The REDs, like the Regist ration Standards before them, do not have the force of law. .

As they first were registered after November 1, 198 4, cholecalciferol and difethialone were not directly subjected to reregistration requirements. However, these chemicals plus warfari n and difethialone were subject to the risk mitigation measures in the 1998 Rodenticide Cluster RED.9 Apart from reregistration activities, EPA took several sp ecific actions to promote safer use of commensal rodenticides. In 1983, EPA issued PR Notice 83- 5 which summarized EPA policy regarding the use of bait stations and noted that label statements such as “Treated baits should be placed in locations not accessible to children, pets, wildlife, and domestic animals, or in tamper-proof bait boxes” had been required to be stated on rodenticide labels beginning during the 1960’s. That text was modified over time by replacing the word “should” with “must.” EPA cho se to highlight this language regarding the use of bait stations because the Agency had concluded that “b ait protection practices directed by labels usually were not being followed.”

On September 16, 1994, EPA issued PR Notice 94-7 (http://www.epa.gov/PR_Notices/pr94-7.html) to update and replace PR Notice 83-5. PR Notice 94-7 replaced the term “tamper-proof,” which was used in PR Notice 83-5, with “tamper resistant” and e xpanded the associated label text to indicate the characteristics of tamper-resistant bait stations. PR Notice 94-7 listed criteria for “tamper-resistant bait stations” and also defined, for EPA registration pur poses, “commensal rodents” to include only, Norway rats ( Rattus norvegicus ), roof rats ( Rattus rattus ), and house mice ( Mus musculus ).

In 1993, EPA consulted with the Fish and Wildlif e Service (the Service) under the Endangered Species Act on certain uses of rodenticides, and in 1993, as part of that consultation, the Service issued a biological opinion finding that a number of rodenticides, including several addressed and analyzed in this action, will likely jeopardize a number of animal sp ecies. The 1993 jeopardy dete rminations can be found in EPA’s “Comparative Ecological Risk Asse ssment for Nine Rodenticides” (Erickson and Urban, 7/2004), available under docket number EPA-HQ-OPP-2006-0955 at www.regulations.gov

. 1998 Rodenticide Cluster and Zinc Phosphi de Reregistration Eligibility Decisions

EPA completed REDs for the Rodenticide Cluste r (brodifacoum, bromadiolone, chlorophacinone, diphacinone and its sodium salt, bromethalin, and piva l and its sodium salt) and a separate RED for zinc phosphide in July 1998. These decisions included comp rehensive reassessments of the required data and the use patterns of affected products that were register ed at the time that the REDs were issued including control of commensal and field rodents, and some non-rodent species controlled by these products in and around buildings, in vineyards, orch ards, rangelands, and field crops. While the 1998 REDs only formally assessed the rodenticide active ingred ients brodifacoum, bromethalin, bromadiolone chlorophacinone, diphacionone and its sodium salt, and zinc phosphide, the Agency required that the same risk mitigation measures be adopted for the registrations of certain other rodenticide active ingredients , namely warfarin and its sodium salts, difethial one, cholecalciferol (vitamin D-3), and red squill. These mitigation measures also were to be adopted for products made with any future newly registered active ingredients that cl aimed to control commensal rodents.

EPA concluded in 1998 that then

- registered uses for brodifacoum, bromadiolone, chlorophacinone, diphacinone and its sodium salt, bromethalin, and zi nc phosphide, with additional labeling requirements and a number of risk mitigation measures, woul d not cause unreasonable risks to humans or the environment and , therefore , were eligible for reregistration. In 1998, EPA determined that all uses of pival and its sodium salts were ine ligible for reregistration. Prior to 1998, pival and its sodium salt was suspended by the Agency in December 1994 for failure of the sole technical registrant, Bell Laboratories, Inc., to respond to the Agency’s Data Call-In Noti ce (DCI) and submit the required data to support the10 continued registration. In 2002, Bell Laboratories, Inc. ’s pival and its sodium salt technical registrations were canceled for failure to pay registration maintenance fees.

The 1998 REDs identified ways in which the risk co ncerns posed from the use of these products could be addressed while still maintaining the benefits afforded by their use. Via the 1998 REDs, the Agency put forth a two-phased approach to mitigating risk. Th e first phase called for the following short-term mitigation measures:

 Non-agricultural rodenticide bait products must in corporate indicator dyes that will help identify when a child has been exposed.

 Non-agricultural rodenticide bait products must in corporate a bittering agent that could make the bait less palatable to children and therefor e reduce the likelihood of consumption.

 Labels which then allowed placement of roden ticide bait “in and around buildings” were required to be amended to “indoors and against the outsi de walls of buildings.” Rat and mouse bait placements were to be allowed “around” buildings on ly if registrants demonstrated that secondary risks to birds and mammals were likely to be minimal.

 All rodenticide products formulated as tracking powders would remain classified and labeled as RUP and tracking powder products were to require additional personal protective equipment (PPE).

 All products labeled for field uses, except for t hose limited to manual unde rground baiting, were to be reclassified and relabeled RUP.

The proposed Phase I requirements were never enacted a nd have been superseded by action taken via the RMD.

The goal of the second phase was to reduce accidental rodenticide exposure to children, pets, and nontarget wildlife in the long term by encouraging the development of exposure/risk reduction technologies. A stakeholder group was organized to provide th e Agency recommendations on how to significantly reduce exposures to rodenticides. This stakehol der group became the Rodenticide Stakeholder’s Workgroup (RSW), which included a broad range of stakeholders and government representatives, including the Centers for Disease Control (CDC), U.S. Department of Agriculture (USDA), EPA, members of the medical community, rodenticide manu facturers, public interest groups, members of the general public, and the veterinary comm unity. The 1998 Rodenticide Cluster RED specified that this stakeholder group was to be formed within 120 days following the publication of the RED and that the group’s recommendations were to be provided to the Agency 9 months after the RED’s publication. To further examine the ecological risks associated with roden ticide use, the Agency began drafting/conducting a comparative ecological risk assessment for rodenticides in 1999.

At the time of the 1998 Rodenticide Cluster RED’ s publication, EPA became aware of new wildlife incident data that suggested that there may be a potential exposure problem involving the active ingredient brodifacoum. This data was reviewed by the Agency and considered in the rodenticide decisions that followed the 1998 RED.

1998-2008

1999-2001 - Rodenticide Stakeholder’s Workgroup (RSW)11 The RSW was formed in 1999 as a subcommittee unde r the federally-chartered advisory body, the Pesticide Program Dialogue Committee (PPDC), to consid er the risks to children of accidental rodenticide exposure and potential measures to reduce such e xposures. The RSW met five times in 1999, and ultimately issued a report recommending that EPA no t require, as proscribed in the 1998 RED, the indicator dye, as no suitable dye had been identified at that time, and not require the bittering agent, due to concerns that it might adversely affect the effi cacy of rodenticide baits. The work group recommended that EPA allow manufacturers to include bittering agents on a voluntary basis. 2 The Agency adopted the RSW’s recommendations, and in November 2001, EPA i ssued a Federal Register Notice (66 FR 59425) announcing that it was amending the two rodenticide RE Ds to allow reregistration of rodenticide bait products without requiring the incorporation of a bittering agent and indicator dye.

By 2001, many rodenticide registrants voluntarily inco rporated a bittering agent into rodenticide products. Acceptable efficacy data were submitted to the Agency to support the registrations of rodenticide bait products that contain a bittering agent. Consequent ly, the addition of bittering agents remains at the discretion of the registrants of commensal rodenticide baits.

1999-2004 – Comparative Ecological Assessment Developed & Refined

In the 1998 REDS, the Agency concluded that furthe r evaluation of the ecological risks of rodenticides was necessary. As part of this work, the Agency conducted a comparative ecological assessment in which nine rodenticide 3 active ingredients were evaluated, compar ed, and ranked among one another in terms of potential primary and secondary risks to birds and n on-target mammals. The risk conclusions from the comparative ecological assessment were based on co mparative analysis modeling and multiple lines of evidence including acute toxicity, persistence of co mpounds in body tissues of primary consumers (i.e. bait eaters), information from laboratory and pen studi es in which poisoned prey were 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.

Due to the public interest in rodenticides, the Agency elected to employ the full six-phase public participation process for the comparative ecological ri sk assessment. (The public participation process that EPA applies to its reregistration eligibility decisi ons is described in a May 14, 2004 Federal Register Notice (69 FR 26819). Between October 1999 and Sept ember 2001, the comparativ e risk assessment was drafted by Agency scientists and it underwent intern al and external peer review. During the Phase 1 comment period that closed in December 2001, the Rodenticide Registrant Task Force (RRTF) raised some issues that led to additional technical work by EPA scientists. After that work was completed, the preliminary risk assessment was made available for public comment in January 2003. EPA accepted public comment s on the document through May 30, 2003. Then, the Agency reviewed and responded to the public comments and revised the ri sk assessment based upon those comments.

2 The RSW also considered requiring that rodenticide baits be sold in ready-to-use tamper-resistant bait stations. At that time, however, there were no r eady-to use bait stations on the market that had been shown to meet EPA’s criteria for tamper-resistance. For that reason, amon g others, the RSW recommended against requiring tamperresistant bait stations.
3 The Comparative Ecological Assessm ent included the active ingredients brodifacoum, bromadiolone, bromethalin, cholecalcierol, chlorophacinone, difethialone, diphacinone, warfarin, and zinc phosphide.12 In September 2004, the Agency opened Phase 5 of the public participation process by publishing the revised comparative ecological risk assessment, whic h incorporated new ecological incident data and reflected revisions made in response to public co mments on the preliminary version of the assessment. Along with the revised ecological assessment, EPA also published a document discussing the benefits associated with rodenticide products and EPA’s pr eliminary position on appropriate risk reduction options. EPA accepted public comments on those do cuments through January 2005. All of these documents and the associated comments can be found in docket EP A-HQ-OPP-2006-0955 at www.regulations.gov.

2004 – West Harlem Environmental Action (WEAC T) & Natural Resources Defense Council (NRDC)

In November 2004, WEACT and NRDC filed suit in the District Court for the Southern District of New York, challenging EPA’s 2001 reversal of its 1998 dete rmination that rodenticide bait products posed an unreasonable risk of harm to children unless they cont ained a bittering agent and an indicator dye. In August 2005, the District Court upheld EPA’s 2001 de termination that an indicator dye should not be required. (380 F.Supp.2d 289 (S.D.N.Y. 2005)) However, the court reversed EPA’s decision to rescind the bittering agent requirement, and remanded the decisi on to EPA for further consideration. The court’s decision gave focus to EPA’s ongoing efforts to de termine how best to reduce exposure and risks to children from rodenticide products.

2005 – Endangered Species Consultation with U. S. Fish and Wildlife Service (the Service)

In March 2005, EPA initiated informal consultation under section 7(a) of the Endangered Species Act, 16 U.S.C. §1536(a), for the nine commensal use roden ticides registered at that time for the purpose of obtaining technical assistance in identifying the full suite of listed species that may be affected by the full range of uses of these products, and to determine whet her further, formal consultation would be necessary and if so, to explore possible mitigation relative to sp ecific species that may be affected. Several reported incidents have involved Federally listed threatened and endangered species, for example the San Joaquin kit fox and Northern spotted owl, in addition to th e Bald eagle, which is protected under the Bald and Golden Eagle Act. The Service previously issued a biological opinion on eight of the rodenticides in 1993. 4 The jeopardy determinations in that opinion for the individual compounds primarily recommend prohibiting use in habitat occupied by listed speci es and requiring tamper-resistant bait stations for outdoor placements for some uses. The 1993 je opardy 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

. 2007 Proposed Risk Mitigation Decision

On January 17, 2007, EPA published a Proposed Risk Mitigation Decision for the nine commensal use rodenticides registered at that time. 5 To minimize children’s exposure to rodenticide products used in homes, EPA proposed requiring that all rodenticide bait products available for sale to consumers be marketed only in tamper-resistant bait stations with solid bait blocks as the only permissible bait form.

4 The biological opinion does not include difethialone, which was first registered in 1995, or difenacoum, which was first registered in 2007.
5 Difenacoum was not included in the Proposed Risk Mitig ation Decision because it was not registered at the time that the proposed decision was issued.13 To mitigate ecological risks, the January 2007 pro posal included a requirement to classify all bait products containing the SGAR active ingredients brodifacoum, bromadiolone, and difethialone as restricted use pesticides, thus making them ava ilable for purchase and use only by trained, certified pesticide applicators or persons under their direct supe rvision. These three rodenticides were identified in the proposal as posing particularly significant risks to non-target wildlife.

EPA received more than 700 individual written comme nts on the January 2007 Proposed Risk Mitigation Decision, plus a letter from an advocacy group that was signed by more than 6,000 of the group’s members. Individual comments were received from a diverse range of stakeholders, including government agencies, city governments, nongovernment al organizations (NGOs), wildlife rehabilitators, professional pest control operators, livestock producers, rodenticide registrants, and interested citizens. 6

Many comments, including those received from the U. S. Department of Housing and Urban Development (HUD), the Centers for Disease Control and Prevention (CDC), several NGOs, and some citizens, articulated support for EPA’s proposal. Other comments, particularly those received from citizens or NGOs who work with, or advocate for wildlife, argued th at the Agency’s risk mitigation proposal did not provide sufficient protection for children and/or wild life. Other comments, mainly those received from rodenticide registrants and livestock producers, cl aimed that the risks posed by use of commensal rodenticides did not warrant the proposed mitigation or that the proposed mitigation was overreaching.

The 2007 Proposed Risk Mitigation Decision, relate d support documents, all comments received, and the Agency’s responses to the comments received can be found at www.r egulations.gov u nder docket number EPA-HQ-OPP-2006-0955. Responses to comments relate d to ecological risk, human health, economic analyses, and risk mitigation are addressed in separ ate documents prepared by the Environmental Fate and Effects Division (EFED), the Health Effects Division (HED), the Biological and Economic Analysis Division (BEAD), and the Special Review and Rere gistration Division (SRRD) (now known as Pesticide Re-evaluation Division (PRD)). These documents provi ded additional detail on the Agency’s rationale for this proposed mitigation decision.

2008 Risk Mitigation Decision for Ten Rodenticides

EPA issued the RMD on May 28 2008. This docum ent was formally published in the Rodenticides docket (EPA-HQ-OPP-2006-0955) on June 4, 2008. The RMD was the Agency’s final decision on the reregistration eligibility of rodenticide products containing brodifacoum, bromadiolone, bromethalin, chlorophacinone, cholecalciferol, difenacoum, difeth ialone, diphacinone (and it s sodium salt), warfarin (and its sodium salt), and zinc phosphide. The RM D also constituted the Agency’s final action in response to the remand order in West Harlem Environmental Ac tion and Natural Resources Defense Council v. U.S. Environmental Protection Agency , 380 F.Supp.2d 289 (S.D.N.Y. 2005). The RMD specifically focuses on commensal use rodenticides and identified a variety of mitigation measures necessary to prevent rodenticides from causing unreas onable adverse effects to human health and the environment. To address unacceptable risk to child ren, pets, and non-target wildlife, the Agency

6 EPA initially provided for a 60-day co mment period for the Proposed Risk M itigation Decision. But after receiving several requests for a comment period extension, the Agency extended the comment period by another 60 days. The comment period closed on May 18, 2007.14 announced that it would require a number of mitig ation measures for commensal use rodenticide products.

To minimize children’s exposure to r odenticide products used in homes, the Agency would require that all rodenticide bait products marketed to general a nd residential consumers be sold only with tamper resistant bait stations, with loose bait (e.g., pellets an d meal) as a prohibited bait form. To reduce wildlife exposures and ecological risks, the Agency would require sale and distribution limits intended to prevent general consumers from purchasing residential use ba it products containing four of the ten rodenticides that pose the greatest risk to wildlife (the S GARs – brodifacoum, bromadiolone, difenacoum, and difethialone). Moreover, tamper-resistant bait sta tions would be required for all outdoor, above-ground uses of commensal use rodenticide products.

EPA afforded registrants three years time to design and im plement the mitigation measures, particularly since the development of bait stations was believed to require time to test and gain approval. The RMD thus provided that until June 4, 2011, registrant s who agreed to cancel or amend their rodenticide registrations consistent with the RMD could continue to sell or distribute their (then) registered rodenticide products without the risk mitigation meas ures described in the RMD. EPA asked registrants to advise EPA by September 2, 2008, whether they w ould voluntarily adopt the risk mitigation measures described in the RMD.

2008 to Present: RMD Implementation

By September 2008, EPA had been informed by three registrants that they did not intend to voluntarily bring their rodenticide products into compliance with the requirements of the May 2008 risk mitigation decision. Reckitt Benckiser Inc. specified that they did not intend to voluntarily amend the registrations of any of their rodenticide products. Liphatech Inc. in formed the Agency that they planned to voluntarily conform some of their products to the RMD, but not all. Woodstream, Inc. also stated that they did not intend to comply

. However, all Woodstream Inc. registrations that did not conform with the RMD were amended to include expiration dates such that the registrations of those products they chose not to conform to the RMD expired on June 4, 2011. Spect rum Group, a Division of United industries, initially informed the Agency that they would voluntarily cancel their non-conforming rodenticide products only to rescind their request for voluntary cancellation prior to the request for cancellation being published in the Federal Register (an administrative requirement of the voluntary cancellation process). All other registrants informed the EPA that they would amend their commensal rodenticide registrations to conform to the RMD, that the RMD did not apply to their rodenticide product(s), or that they were requesting voluntary cancellation of their rodenticide produc t(s) to be effective on or before June 4, 2011. Also, since 2008, both Reckitt Benckiser Inc. and Liphat ech Inc., have registered homeowner rodenticide products that conform to the RMD, although they still refuse to amend certain other products. For a list of homeowner rodenticide products that conform to the RMD, see http:// www.epa.gov/pesticides/miceand-rats/rodent-bait-station.html.

2010 Reckitt Benckiser Inc. vs EPA

Following Reckitt Benckiser informing EPA that it did not intend to voluntarily adopt the mitigation measures in the RMD, Reckitt Benckiser requested th at EPA initiate cancellation proceedings for Reckitt Benckiser’s affected rodenticide products. EPA in formed Reckitt Benckiser Inc. it intended to take15 action, but not at that time. Reckitt Benckiser file d a federal legal complaint in District Court (See, Reckitt Benckiser, Inc. v. Jackson, 762 F. Supp. 2d 34, 46 (D.D.C. 2011)). Ultimately, the court addressed only “whether EPA has the authority unde r FIFRA to bring enforcement proceedings for misbranding before, or rather than, regulatory can cellation proceedings under FIFRA Section 6 against products not voluntarily complying with a reregistration RMD.” On this narrow issue, the court found for Reckitt Benckiser.

Referenced Documents

 Potential Risks of Nine Rodenticides to Birds, and Nontarget Mammals: A Comparative Approach

http://www.regulations.gov/#!documentDeta il;D=EPA-HQ-OPP-2002-0049- 0002;oldLink=false

 Risk Mitigation Decision for Ten Rodenticides

http://www.regulations.gov/#!documentDeta il;D=EPA-HQ-OPP-2006-0955- 0764;oldLink=false

 Rodenticide Cluster Reregistration Eligibility Decision

http://www.epa.gov/oppsrrd1/reregistration/REDs/2100red.pdf

 Warfarin and it Sodium Salts Rere gistration Eligibility Decision

http://www.epa.gov/oppsrrd1/REDs/old_reds/warfarin_salt.pdf

 Zinc Phosphide Reregistration Eligibility Decision

http://www.epa.gov/oppsrrd1/reregistration/REDs/2100red.pdf