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Introduction:

This is the Environmental Protection Agency’s (EPA or the Agency) Final Work Plan (FWP) 

for the registration review of piperalin. The FWP includes the expected registration review time 

line. The FWP also addresses public comments received concerning the Preliminary Work Plan

(PWP) in the Summary Document, which was posted on the piperalin registration review docket 

(EPA-HQ-OPP-2009-0483). The Summary Document provided information on what EPA 

knows about the pesticide and what additional risk analyses and data or information the Agency 

believes are needed to make a registration review decision. 

The Agency’s implementation of the registration review program requires review of each 

registered pesticide every 15 years to determine whether it continues to meet the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA) standard for registration. Changes in 

science, public policy, and pesticide use practices will occur over time. 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 that statutory standard. The public 

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

on this program is provided at http://www.epa.gov/oppsrrd1/registration_review. 

Piperalin was first registered in 1964 to treat powdery mildew fungal infections of ornamental 

plants in greenhouses. Currently, piperalin is registered exclusively for use to control powdery 

mildew on ornamental plants, shrubs, vines, and trees grown in commercial greenhouses and 

other similar enclosed structures with nonporous coverings. There are no registered outdoor or 

residential uses. 

Comments Received on the PWP:

The piperalin registration review docket received twelve comments during the 60-day comment 

period on the PWP, which began on September 23, 2009 and ended on November 23, 2009. The 

comments received do not change the data and risk assessment needs or the timeline detailed in 

the piperalin PWP. However, a mistake was noted in the timeline detailed in the piperalin PWP. 

The PWP indicated the Final Work Plan would be completed in January, instead of the correct 

date, which is February 2010. 

This document finalizes the work plan for the piperalin registration review process. A 

description of the comments received and the Agency’s response to these comments is available 

in the “Summary of Comments and Agency Responses” section of this document. 
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Risk Assessment and Data Needs:

The Agency anticipates updating the occupational human health risk assessment for piperalin.

Ecological Risk 

• Based on both the indoor-only use pattern for piperalin and EPA’s determination that, when 

used according to the label, environmental exposures from piperalin are negligible, the 

Agency believes that the currently registered uses of piperalin will have no effect on listed 

species or their designated critical habitat. As a result, the Agency does not anticipate 

undertaking any further assessment relative to the Endangered Species Act. If, in the future, 

piperalin is considered for registration for uses that could result in environmental exposures, 

further analysis will be undertaken to determine potential effects to federally listed threatened 

or endangered species and their designated habitats. 

• Please refer to Registration Review: Preliminary Problem Formulation for Ecological Risk, 

Environmental Fate, Endangered Species, and Drinking Water Assessments for Piperalin, 

dated May 28, 2009, located in the piperalin docket, for further details. 

Human Health Risk 

• The Agency anticipates developing an updated occupational exposure assessment during 

registration review. A new occupational risk assessment is anticipated to incorporate the 

toxicity data that the Agency expects to require and to make necessary updates and changes 

based on any standard protocols, assumptions, and algorithms that may have changed since 

the last occupational exposure assessment was conducted. 

• The Agency anticipates requiring the following toxicology studies: 

○ 28-Day Inhalation Toxicity Study (GLN 870.3465)

○ Reproductive Toxicity Study (rat) (GLN 870.3800)

○ Developmental Toxicity Study (rabbit) (GLN 870.3700b)

○ Neurotoxicity Battery (Acute and Subchronic Studies) (GLN 870.6200)

○ Immunotoxicity (GLN 870.7800)

• Please refer to Piperalin: Human Health Assessment Scoping Document in Support of 

Registration Review, dated August 25, 2009, located in the piperalin docket, for a detailed 

discussion of the anticipated human health risk assessment needs. 

Other Data Needs

• The Agency anticipates requiring the following product chemistry study: 

○ UV/Visible Absorption (GLN 830.7050) 
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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 is issuing 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. 

Piperalin 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/. 
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Timeline:

EPA has created the following estimated timeline for the completion of the piperalin registration 

review. 

Registration Review for Piperalin 

Projected Registration Review Timeline 

Milestone Estimated 

Month/Year 

Opening the Docket 

Open Docket & Public Comment for Preliminary Work Plan Sept. 2009 

Close Public Comment Nov. 2009 

Case Development 

Final Work Plan Feb. 2010 

Issue DCI Oct.-Dec. 2010 

Data Submission Oct.-Dec. 2012 

Open Public Comment for Preliminary Risk Assessment Apr.-Jun. 2014 

Close Public Comment Period July-Sept. 2014 

Registration Review Decision 

Open Public Comment for Proposed Registration Review 

Decision 

Oct.-Dec. 2014 

Close Public Comment Jan.-Mar. 2015 

Final Reg Review Decision and begin post-decision follow-up 2015 

Total 6 years 

Summary of Comments and Agency Responses:

The piperalin registration review docket was open for a 60-day comment period beginning on 

September 23, 2009. During that time, the Agency received one comment from the registrant 

and several comments from commercial flower growers in California. The Agency has 

concluded that these comments do not warrant a change in the work plan or the timeline set out 

in the PWP. Therefore, this document is the final work plan for the piperalin registration review 

process. 

In the PWP, the Agency solicited comments on three specific topics: environmental justice, 

water body impairment, and trade irritants. No comments or information were received during 

the comment period concerning these issues.

Summary of comments from SePRO Corp., 2G Roses LLC, CA Cut Flower Commission, Koch 

Mesa Nursery Inc., Green Valley Floral Inc., Ocean Breeze International, B&H Flowers, 

Kitayama Brothers Inc., and Dramm & Echter Inc. 

1. Comment: The commenters explained how piperalin is an essential component of the 

Integrated Pest Management programs employed by greenhouse ornamental flower 

growers. Piperalin is the only active ingredient available domestically for curative 

control of powdery mildew infections. In the absence of piperalin products growers 
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would have to rely on various broad spectrum preventative fungicides, which would 

increase exposure to potentially harmful chemicals. Furthermore, the added expense of 

alternatives to piperalin products would put domestic flower growers at a competitive 

disadvantage against international growers with access to piperalin products. 

Commenters are not aware of any safety incidents ever having been reported. 

Response: The Agency appreciates the feedback and will take the comments into 

consideration during the risk assessment process. 

2. Comment: SePRO Corp. commented on their intention to seek waivers for the 

registration review data requirements based on the low-volume of production and use of 

piperalin. 

Response: The Agency will consider waiver requests either as a response to the 

piperalin DCI or prior to the issuance of the DCI depending on when they are received. 

Next Steps:

The Agency plans to develop a Data Call-In Notice for piperalin and plans to issue it in late2010. This new information will be used to conduct a human health risk assessment for 

piperalin.