Docket Number: EPA-HQ-OPP-2008-0444 

www.regulations.gov

Temephos 

Proposed Registration Review Final Decision 

March 2011 

TABLE OF CONTENTS 

I. INTRODUCTION........................................................................................4

II. BACKGROUND INFORMATION ...........................................................5 

III. PROPOSED REGISTRATION REVIEW FINAL DECISION ..............6 

IV. NEXT STEPS AND TIMELINE ................................................................6

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I. INTRODUCTION 

This document is the Environmental Protection Agency’s (EPA or the Agency) 

Proposed Registration Review Final Decision for temephos and is being issued pursuant 

to 40 CFR § 155.57 and § 155.58. A registration review decision is the Agency’s 

determination whether a pesticide meets, or does not meet, the standard for registration in 

the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). 

 FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, 

mandated the continuous review of existing pesticides. All pesticides distributed or sold 

in the United States must generally be registered by EPA, 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. Through the 

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

that as change occurs, products in the marketplace can be safely used. Information on 

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

In 2006, the Agency implemented the Registration Review program pursuant to 

FIFRA Section 3(g), and will review each registered pesticide every 15 years to 

determine whether it continues to meet the FIFRA standard for registration. 

 Pursuant to 40 CFR § 155.50, the Agency formally initiated registration review 

for temephos (case 0006). The following timeline highlights significant events that have 

occurred during the registration review of temephos: 

• June 25, 2008 – Publication of the temephos Summary Document, Scoping 

Document, and Problem Formulation in the temephos docket (EPA-HQ-OPP2008-0444) for a 90-day public comment period. The Summary Document also 

included the Preliminary Work Plan for the registration review of temephos. 

• November 7, 2008 – Signature of the temephos Final Work Plan and the 

Agency’s response to the public comments received during the 90-day comment 

period on the temephos Summary Document. The one comment received did not 

change the work plan set out in the Preliminary Work Plan. 

• November 10, 2010 – Publication of a Notice of Receipt of requests to voluntarily 

cancel all remaining pesticide registrations containing temephos in the Federal 

Register (75 FR 69073) (FRL-8851-5). The docket number for the receipt of the 

voluntary cancellation is EPA-HQ-OPP-2009-1017. During the 30-day comment 

period, comments were received regarding temephos from the American 

Mosquito Control Association and the IR-4 Project. Both organizations 

emphasized the benefits of temephos as it is used in public health for mosquito 

control and requested that EPA extend the comment period for these product 

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cancellations. However, the Agency recognizes the role of temephos in mosquito 

control and has agreed to a 4-year phase-out of the product registrations to 

accommodate this need and allow registrants time to develop replacement 

products. The current temephos products would not be cancelled until December 

30, 2015. For these reasons, the Agency did not extend the comment period. 

• February 25, 2011 – Publication of the Product Cancellation Order for all 

remaining pesticide registrations containing temephos in the Federal Register (76 

FR 10587) (FRL-8863-4). 

II. BACKGROUND INFORMATION 

Temephos is a non-systemic organophosphate insecticide which is applied to 

standing water, shallow ponds, lakes, woodland pools, tidal waters, marshes, swamps, 

waters high in organic content, highly polluted water, catch basins (and similar areas 

where mosquitoes may breed), stream margins, and intertidal zones of sandy beaches. 

Target pests include aquatic larvae of mosquitoes, midges, gnats, punkies, and sandflies. 

Temephos is one of a few organophosphates registered to control mosquito larvae, and is 

the only organophosphate with any appreciable larvicidal use. There are no crop uses 

and no residential uses. Temephos is currently labeled for application only by public 

health officials, personnel of mosquito abatement districts, and other similar government 

agencies or personnel under contract to these entities. The most recent environmental 

fate, ecological, and human health risk assessments for temephos were completed in 1999 

in support of the temephos Reregistration Eligibility Decision (RED), which was 

completed in July 2001. 

 After the Final Work Plan was signed in November 2008 as part of the 

registration review process for temephos, the technical and end-use product registrants, 

Clarke Mosquito Control Company, Inc. and Value Garden Supply, informed the Agency 

that they were requesting to voluntarily cancel all of their temephos product registrations. 

These were the last remaining products registered in the U.S. containing temephos. A 

Notice of Receipt of requests to voluntarily cancel all pesticide registrations containing 

temephos published in the Federal Register on November 10, 2010. 

The Agency then issued the product cancellation order on February 25, 2011 for 

all remaining temephos product registrations. Copies of those documents are included in 

the docket for this registration review. As specified in the Cancellation Order, registrants 

are prohibited from selling or distributing existing stocks of products containing 

temephos for all uses as of December 31, 2015. After December 31, 2016, persons other 

than registrants are prohibited from selling or distributing existing stocks of products 

containing temephos labeled for all uses. After December 31, 2016, existing stocks of 

products containing temephos labeled for all uses, already in the hands of users, can be 

used legally until they are exhausted, provided that such use complies with the EPAapproved label and labeling of the affected product. 

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III. PROPOSED REGISTRATION REVIEW FINAL DECISION 

As stated in the temephos Preliminary Work Plan, the Agency had intended to 

revise the existing risk assessments for temephos. However, due to the cancellation order 

issued affecting all temephos product registrations in the United States, the Agency has 

found that it is not necessary to conduct new risk assessments for temephos and is, 

therefore, issuing a proposed decision pursuant to 40 CFR Part 155.53(c)(2) and 40 CFR 

Part 155.58. The voluntary cancellation of all remaining U.S. temephos registrations will 

become effective the same year as the final registration review decision would be 

completed. The anticipated registration review timeline introduced in the temephos 

Preliminary Work Plan changed due to the issuance of the temephos DCI in April 2010. 

If the temephos registrations had not been voluntarily cancelled, the Agency would issue 

the preliminary risk assessments by January 2014 and issue the revised risk assessments 

by July 2014, with a final registration review decision scheduled for completion by May 

2015. 

The Agency does not expect the current risks associated with temephos use to 

differ from those identified during the temephos reregistration process. In order to 

mitigate the risks identified during reregistration, the Agency specified mitigation 

measures in the temephos RED, which are already in effect on temephos product labels. 

The existing stocks, sales, and distribution deadlines included in the February 25, 2011 

cancellation order ensure that temephos sale, distribution, and use will decline and 

eventually cease entirely in the United States in the future. During this period, given the 

mitigation measures that are specified in the RED and are currently in place, the Agency 

believes that existing stocks of temephos products may be used until depleted without 

causing unreasonable risk to human health and the environment. Pursuant to 40 CFR § 

155.57 and 155.58, the Agency proposes that the registration review final decision be 

issued, thus concluding the temephos registration review for the reasons discussed above. 

The affected product registrations are subject to the terms and conditions of the February 

25, 2011 cancellation order. 

IV. NEXT STEPS AND TIMELINE 

Pursuant to 40 CFR § 155.58, this proposed registration review final decision 

document is being entered into the temephos docket (EPA-HQ-OPP-2008-0444). A 

Federal Register notice will announce the availability of this proposed registration 

review final decision for temephos and allow a 60-day comment period. If there are no 

significant comments or additional information submitted to the docket during the 

comment period that leads the Agency to change its decision, EPA will issue a 

registration review final decision for temephos, Case 0006, which will be announced in 

the Federal Register. The Agency anticipates that the final decision will be issued by 

mid 2011.