Docket Number: EPA-HQ-OPP-2010-0214 

www.regulations.gov 

Pyridaben Summary Document 

 Registration Review: Initial Docket 

 September 2010 

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TABLE OF CONTENTS 

I. Preliminary Work Plan (PWP) 4 

II. Fact Sheet 11 

________________________________________ 

Please Note 

This Preliminary Work Plan and Fact Sheet summarize the Environmental Protection Agency's 

current position based on the following documents: 

1. Registration Review: Preliminary Problem Formulation for the Ecological Risk and 

Drinking Water Exposure Assessments for Pyridaben. August 26, 2010. 

2. Pyridaben. Human Health Assessment Scoping Document in Support of Registration 

Review. May 21, 2010. 

3. Pyridaben: Review of Human Incidents. May 20, 2010. 

4. Screening Level Use Analysis (SLUA) for Pyridaben. October 19, 2009.

5. Appendix A for Pyridaben. July 6, 2009.

Supporting documents for Pyridaben may be found in the docket (EPA-HQ-OPP-2010-0214) 

located on the internet at www.regulations.gov. 
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I. Preliminary Work Plan – Pyridaben 

Introduction:

The Food Quality Protection Act of 1996 mandated a registration review program. All pesticides 

sold or distributed in the United States (U.S.) generally must be registered by the Environmental 

Protection Agency (EPA or the Agency), based on scientific data showing that they will not 

cause unreasonable risks to human health or the environment when used as directed on product 

labeling. The registration review program is intended to make sure that, as the ability to assess 

risk evolves and as policies and practices change, all registered pesticides continue to meet the 

statutory standard of no unreasonable adverse effects to human health or the environment. 

Changes in science, public policy, and pesticide use practices will occur over time. Through the 

registration review program, the Agency periodically reevaluates pesticides to make sure that as 

change occurs, products in the marketplace can be used safely. Information on this program is 

provided at: http://www.epa.gov/oppsrrd1/registration_review/.

The Agency is implementing the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for 

registration. The Agency will consider benefits information and data as required by FIFRA. The 

public phase of registration review begins when the initial docket is opened for each case. The 

docket is the Agency’s opportunity to state what it knows about the pesticide and what additional 

risk analyses and data or information it believes are needed to make a registration review 

decision. After reviewing and responding to comments and data received in the docket during 

this initial comment period, the Agency will develop and commit to a final work plan and 

schedule for the registration review of pyridaben. 

Pyridaben was first registered in 1996 and is used as a miticide/insecticide in orchards and 

vineyards. Pyridaben is formulated as both wettable powder and as an aqueous solution. There 

are no residential uses for pyridaben. Tolerances for pyridaben are established under 40 CFR 

180.494 for residues that result from agricultural uses. 

Anticipated Risk Assessment and Data Needs:

The Agency anticipates conducting a comprehensive ecological risk assessment, including an 

endangered species assessment, for all uses of pyridaben. A drinking water assessment will be 

conducted in order to support future human health risk assessments. Below is a summary of the 

issues relevant to the registration review process of pyridaben. 
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Ecological Risk: 

• The most recent ecological risk assessment for pyridaben was completed in 2004 for uses 

on strawberries, hops, tropical fruits, and stone fruits. 

• The Agency has not conducted a risk assessment that supports a complete endangered 

species determination for pyridaben. The ecological risk assessment planned during 

registration review will allow the Agency to determine whether pyridaben’s use has “no 

effect” or “may affect” federally listed threatened or endangered species (listed species) 

or their designated critical habitats. When an assessment concludes that a pesticide’s use 

“may affect” a listed species or its designated critical habitat, the Agency will consult 

with the U.S. Fish and Wildlife Service and/or National Marine Fisheries Service (the 

Services), as appropriate. 

• Based upon the use pattern and the current database, the Agency anticipates requiring the 

following environmental fate and ecological effects data in order to conduct a complete 

ecological risk assessment, including an endangered species assessment, for all uses: 

o GLN 835.4100 Aerobic Soil Metabolism 

o GLN 835.4300 Aerobic Aquatic Metabolism 

o GLN 835.4400 Anaerobic Aquatic Metabolism 

o GLN 835.6100 Frozen Storage Stability 

o GLN 835.6200 Environmental Chemistry Analytical Method and Independent 

Laboratory Validation for Residues in Water (see 40 CFR § 158.1300 note 7) 

o GLN 835.6100 Environmental Chemistry Analytical Method and Independent 

Laboratory Validation for Residues in Soil (see 40 CFR § 158.1300 note 7) 

o GLN 850.1710 Bioconcentration in oysters 

o GLN 850.1850 Aquatic food chain transfer 

o GLN 850.3040 Field testing for pollinators 

o GLN 850.1075 Estuarine/Marine Fish Acute Toxicity Test 

o GLN 850.1400 Saltwater fish early-life stage test 

o GLN 850.1350 Estuarine/Marine invertebrate life cycle test 

o GLN 850.1735 Whole sediment: acute freshwater invertebrates 

o Special Study Whole sediment: chronic freshwater invertebrates 

o GLN 850.4100 Terrestrial Plant Toxicity Test, Tier II: Seedling Emergence 

o GLN 850.4150 Terrestrial Plant Toxicity Test, Tier II: Vegetative Vigor 

o GLN 850.5400 Aquatic Plant Toxicity Test, Tier II: Algae 

o GLN 850.4400 Aquatic Plant Toxicity Test, Tier II: Vascular Plants 

Registrants may opt to conduct a Tier I studies (GLN 850.4100, 4150, 5400, 

4400) in lieu of a Tier II, with the understanding that any adverse effects (even 

if <25%) will necessitate a Tier II study. A Tier II study will enable the Agency 

to conduct an endangered species assessment for nontarget plants. 
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• Please refer to the document, Registration Review – Preliminary Problem Formulation 

for the Ecological Risk and Drinking Water Assessments for Pyridaben, dated August 26, 

2010, located in the docket for a detailed discussion of the anticipated risk assessment 

and data needs. 

Human Health Risk:

• The most recent human health risk assessment for pyridaben was completed in 2005 for 

use on hops, tropical fruits, strawberries, and stone fruits. 

• Based on the current use pattern, the Agency anticipates requiring the following data in 

order to support a human health risk assessment for pyridaben: 

o GLN 870.7800 Immunotoxicity 

• Following submission of the additional toxicological data, the Agency plans to update the 

human health toxicity profile. 

• As part of registration review, a new dietary risk assessment should be conducted which 

utilizes the most current version of the Dietary Exposure Evaluation Model software with 

the Food Commodity Intake Database. 

• The most recent Tier 1 drinking water exposure assessment was completed in 2004. A 

new drinking water assessment will be conducted to support the anticipated dietary 

exposure assessments of pyridaben in registration review. 

• The livestock dietary burdens should be reassessed to evaluate potential secondary 

residues of pyridaben and its metabolites in/on livestock commodities due to of feed 

items with pyridaben residues resulting from the established food/feed commodities. 

• An updated occupational exposure and risk assessment for all uses will be conducted to 

support registration review. This updated risk assessment will consider any revised 

toxicity endpoints or exposure assessment methodologies. 

• The pyridaben tolerance expression (40 CFR 180.494) will be reviewed during 

registration review to ensure that it appropriately covers the metabolites and degradates 

of pyridaben and that it specifics the residues to be measured for each commodity. 

• Please refer to the document, Pyridaben. Human Health Assessment Scoping Document 

in Support of Registration Review, dated May 21, 2010, located in the docket for a 

detailed discussion of the anticipated risk assessment needs for human health. 
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Other Data Needs: 

• GLN 830.7050 UV/Visible Light Absorption – this study is a new data requirement under 

40 CFR part 158 (Product Chemistry Data Requirements) for registration of a pesticide 

(food and non-food uses). The Agency anticipates requiring this study to obtain basic 

information about the compound’s identity/composition and the wavelengths at which the 

compound may be susceptible to photochemical degradation. 

Endocrine Disruptor Screening Program

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor 

Screening Program (EDSP) to determine whether certain substances (including pesticide active 

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by 

a “naturally occurring estrogen, or other such endocrine effects as the Administrator may 

designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine related effects caused by the substance, and 

establish a quantitative relationship between the dose and the E, A, or T effect. 

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first 

group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. 

This list of chemicals was selected based on the potential for human exposure through pathways 

such as food and water, residential activity, and certain post-application agricultural scenarios. 

This list should not be construed as a list of known or likely endocrine disruptors. 

Pyridaben is not among the group of 58 pesticide active ingredients on the initial list to be 

screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide 

chemicals. Accordingly, EPA anticipates issuing future EDSP orders/data call-ins for all 

Registration Review cases, including those for which EPA has already opened a Registration 

Review docket for a pesticide active ingredient. 

For further information on the status of the EDSP, the policies and procedures, the list of 67 

chemicals, the test guidelines and the Tier 1 screening battery, please visit our website: 

http://www.epa.gov/endo/. 

Timeline:

EPA has created the following estimated timeline for the completion of the pyridaben 

registration review. 
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Registration Review for Pyridaben – Projected Registration Review Timeline

Activities Estimated Date 

Opening the Docket 

Open Docket and Public Comment Period 2010 – September 

Close Public Comment 2010 – November 

Case Development 

Final Work Plan 2011 – February 

Issue DCI 2011 – Oct. – Dec. 

Data Submission 2013 – Oct. – Dec. 

Open Public Comment Period for Preliminary Risk Assessments 2015 – April – June 

Close Public Comment Period 2015 – July – Sept. 

Registration Review Decision 

Open Public Comment Period for Proposed Registration Review 

Decision 

 2015 – Oct. – Dec. 

Close Public Comment Period 2016 – Jan. – March 

Final Registration Review Decision and Begin Post-Decision Follow-up 2016 

Total (years) 6 

Guidance for Commenters:

The public is invited to comment on EPA’s preliminary registration review work plan and 

rationale. The Agency will carefully consider all comments as well as any additional 

information or data provided in a timely manner prior to issuing a final work plan for pyridaben. 

Trade Irritants:

Through the registration review process, the Agency intends to solicit information on trade 

irritants and, to the extent feasible, take steps toward facilitating irritant resolution. Growers and 

other stakeholders are asked to comment on any trade irritant issues resulting from lack of 

Maximum Residue Limits (MRLs) or disparities between U.S. tolerances and MRLs in key 

export markets, providing as much specificity as possible regarding the nature of the concern. 

Water Quality:

Pyridaben is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act, based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=88

5. In addition, no Total Maximum Daily Loads (TMDL) have been developed for pyridaben, 

based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id

=885&p_pollutant_group_name=PESTICIDES. More information on impaired water bodies and 

TMDLs can be found at http://www.epa.gov/owow/tmdl/. The Agency invites submission of 

water quality data for this pesticide. To the extent possible, data should conform to the quality 

standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired 
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Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and 

Management Process (see: 

http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm) in order to ensure they 

can be used quantitatively or qualitatively in pesticide risk assessments. 

Environmental Justice:

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all 

people, regardless of race, color, national origin, or income, in the development, implementation, 

and enforcement of environmental laws, regulations, and policies. To help address potential 

environmental justice issues, the Agency seeks information on any groups or segments of the 

population who, as a result of their location, cultural practices, or other factors, may have 

atypical, unusually high exposure to pyridaben, compared to the general population. Please 

comment if you are aware of any sub-populations that may have atypical, unusually high 

exposure compared to the general population. 

Other Information:

Stakeholders are also specifically asked to provide information and data that will assist the 

Agency in refining the ecological and human health risk assessments, including any speciesspecific effects determinations. The Agency is interested in receiving the following information: 

1. suggestions from stakeholders on ways to reduce non-target organism exposures to 

pyridaben 

2. confirmation on the following label information 

a. maximum application rates 

b. geographic limitations on use 

3. use or potential use distribution (e.g., acreage and geographical distribution of 

relevant crop) 

4. use history 

5. median and 90th percentile reported use rates (lbs. a.i./acre) from usage data – 

national, state, and county 

6. application timing (date of first application and application intervals) by crop – 

national, state and municipality 

7. sub-municipality crop location data 

8. directly acquired municipality-level usage data (not derived from state level data) 

a. maximum reported use rate (lbs. a.i./acre) from usage data – county 

b. percent crop treated – county 

c. median and 90th percentile number of applications – county 

d. total pounds per year – county 

e. the year the pesticide was last used in the county/sub-county area 

f. the years in which the pesticide was applied in the county/sub-county area 

9. state or local use restrictions 
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10. ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian 

and mammalian mortalities) not already reported to the Agency 

11. monitoring data 

Next Steps:

After the 60-day comment period closes, the Agency will review and respond to any comments 

received in a timely manner, and then issue its Final Work Plan (FWP) for the pyridaben 

registration review.
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II. FACT SHEET 

Background Information:

• Pyridaben PC Code: 129105, CAS#: 96489-71-3 

• Technical registrant: Nissan Chemical Industries, Ltd (EPA Company No. 33906) 

• First registered for use in 1996; therefore not subject to Reregistration. 

• There are eleven active FIFRA section 3 registrations and six special local need 24c 

registrations. 

• Pesticide Re-evaluation Division Chemical Review Manager (CRM): Carissa Cyran 

cyran.carissa@epa.gov

• Registration Division Contact: Richard Gebken gebken.richard@epa.gov 

Use & Usage Information: (For additional details, please refer to the Appendix A document in 

the pyridaben docket.) 

• Pyridaben is a miticide/insecticide applied to tree nuts, pistachio, apple, pear, citrus fruits, 

grape, apricot, cherry, nectarine, peach, plum, prune, plumcot, cranberry, ornamentals, 

strawberries, hops, tropical fruit, and greenhouse-grown tomatoes. 

• Pyridaben is formulated as both a wettable powder and as an aqueous solution. 

• Approximately 50,000 pounds of pyridaben were used annually between 2001- 2007. 

Recent Actions:

• A section 24c special local needs (SLN) for the use of pyridaben on pears in four counties 

in Washington was granted in May 2010. This SLN allows a higher rate on pears. 

Ecological Risk Assessment Status: 

The following are key findings of the most recent ecological risk assessments for pyridaben. 

Please refer to the document, Registration Review – Preliminary Problem Formulation for the 

Ecological Risk and Drinking Water Assessments for Pyridaben, located in the docket for a 

detailed discussion of the ecological risk assessment. 

• Pyridaben (parent only), at the maximum uses rates on strawberries, hops, tropical fruit, 

and stone fruit, exceeded acute and chronic risk levels of concern (LOC) for freshwater 

fish and invertebrates, acute risk for estuarine/marine fish and invertebrates, and chronic 

risk for birds and mammals. 

• The avian acute LOC’s were not exceeded. 
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• Bioconcentration of pyridaben in the food chain has been identified as a potential 

concern. 

Human Health Risk Assessment Status:

The following are key findings of the most recent human health risk assessments for pyridaben. 

Please refer to the document, Pyridaben. Human Health Assessment Scoping Document in 

Support of Registration Review, located in the docket for a detailed discussion of the human 

health risk assessment. 

Hazard Characterization:

• An acute neurotoxicity study in rats showed possible neurotoxic effects at the higher 

tested doses. A subchronic neurotoxicity study showed no evidence of neurotoxic 

effects. 

• Carcinogenicity studies for pyridaben do not demonstrate any evidence of cancer, thus 

the chemical is classified as “Not Likely to Be Carcinogenic to Humans.” 

Dietary (Food and Drinking Water): 

• The most recent acute and chronic dietary (food and drinking water) exposure 

assessments were completed in 2005 and were below the Agency’s level of concern for 

the general U.S. population and all population subgroups examined, thus there are no 

dietary risks. 

Residential: 

• There are no residential uses for or exposures to pyridaben; therefore, a residential risk 

assessment has not been conducted. 

Aggregate: 

• Aggregate risks are calculated from combined dietary and residential exposures. Since 

there are no residential uses of pyridaben, aggregate risks are equivalent to dietary risks 

and are below the Agency’s level of concern.

Occupational: 

• An occupational exposure assessment has been conducted for wettable powder 

formulations and showed no risks above the Agency’s level of concern with combined 

(dermal and inhalation) margins of exposure (MOEs) from 110-600 for applicators and 

1,700-36,000 for mixer/loaders. 
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• An occupational exposure assessment has been conducted for postapplication dermal 

exposure and showed no risks above the Agency’s level of concern with MOEs from 

100-790. 

• Postapplication inhalation exposure and risk was not quantitatively assessed. The12 hour 

re-entry interval (REI), as required in the Worker Protection Standard, is on the current 

labels. 

• Past pyridaben risk assessments rely in part on data from studies in which adult human 

subjects were intentionally exposed to a pesticide to determine their dermal and 

inhalation exposure. Many such studies, involving exposure to many different pesticides, 

comprise generic pesticide exposure databases such as the Pesticide Handlers Exposure 

Database (PHED) and the Agricultural Reentry Task Force (ARTF) Database. EPA has 

reviewed all the studies supporting these multi-pesticide generic exposure databases, and 

has found no clear and convincing evidence that the conduct of any of them was either 

fundamentally unethical or significantly deficient relative to the ethical standards 

prevailing at the time the research was conducted. All applicable requirements of EPA’s 

Rule for the Protection of Human Subjects of Research (40 CFR Part 26) have been 

satisfied, and there is no regulatory barrier to continued reliance on these studies.

Cumulative

• The Agency has not determined whether pyridaben shares a common mechanism of 

toxicity with other chemical substances. If, in the future, the Agency determines that new 

information on pyridaben is available that could potentially impact a cumulative risk 

assessment and result in a risk of concern, the Agency will revisit a cumulative risk 

assessment. 

Incidents:

• The Office of Pesticide Programs Incident Data System (IDS) was reviewed for reports 

of pyridaben human incidents. Based on the low number and severity classification (i.e., 

11 cases, classified as either low or moderate severity), there does not appear to be a 

concern at this time that would warrant further investigation. 

• No ecological incidents have been reported from 2002 to the present associated with the 

use of pyridaben. 

Data Call-In Status:

• No DCIs have been issued for pyridaben. 
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Tolerances and International Harmonization: 

• Tolerances are established under 40 CFR 180.494 for residues that result from 

agricultural uses.

• The permanent tolerance expression for all commodities is in terms of the parent only for 

plant commodities, and parent plus the metabolites PB-7, and PB-9 for livestock 

commodities. 

• Where possible, EPA encourages the harmonization of U.S. tolerances and Maximum 

Residue Limits (MRLs) in key export markets. A table noting the U.S. tolerances, 

Canadian MRLs, and Codex MRLs for pyridaben is located in the Human Health 

Assessment Scoping Document in Support of Registration Review. The Agency will 

work to harmonize tolerances/MRLs, where possible, during registration review. 

Labels: 

 

• The labels for pyridaben (EPA Reg. Nos. 33906-16, 33906-19, 33906-20, 33906-21, 

33906-22, 33906-23, 33906-24, 81880-3, 81880-4, 81880-5, and 81880-7) can be 

obtained from the Pesticide Product Label System (PPLS) website: 

http://oaspub.epa.gov/pestlabl/ppls.home.