4695 MacArthur Court, Suite 1200, Newport Beach, CA , 92660 ∙ Phone (949) 260-1200 

{00280.055 / 111 / 00115678.DOCX 2}

June 24, 2013

Via E-Mail and Federal Express

Office of the Hearing Clerk (1900L)

U.S. Environmental Protection Agency 

1200 Pennsylvania Ave., NW.

Washington, DC 20460-0001

Re: EPA-HQ-OPP-2012-0441: Objection to Order Revoking

Difenzoquat Tolerances

To Whom It May Concern:

By this letter, Amvac Chemical Corporation (AMVAC) submits to the United States 

Environmental Protection Agency (EPA) a formal objection to the order revoking difenzoquat tolerances 

under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).1

 On May 29, 2013, EPA issued a 

Federal Register notice announcing the revocation, effective May 29, 2013, of all tolerances for the 

pesticide difenzoquat.2

 The tolerances at issue are “import tolerances” as all domestic difenzoquat 

registrations have been cancelled. The purpose of AMVAC’s objection is to seek an extension of the 

effective date of the revocation for the reasons discussed below.

Unfortunately, AMVAC inadvertently overlooked the notices that preceded the May 29,

2013, revocation order and, due to this oversight, did not submit a comment or response within the time 

periods provided. Because AMVAC is no longer a U.S. registrant of difenzoquat products, AMVAC received no 

direct notice of these actions. For the reasons discussed more fully below, AMVAC respectfully requests that 

EPA modify the effective date for this tolerance revocation to take into account the lawful use of difenzoquat 

products currently taking place in Canada. AMVAC has notified the Pest Management Regulatory Agency 

(PMRA) of its intent to cancel all Canadian registrations and AMVAC expects that existing stocks of currently 

registered products likely would not be applied beyond 2015. The extension requested is intended solely to 

allow a viable transition period for those Canadian growers who lawfully apply difenzoquat and for lawfully 

treated commodities to pass through the channels of trade. AMVAC believes that this would occur by 

December 31, 2017, and thus suggests an extension until that date. 

Set forth below are the facts related to the order revoking difenzoquat tolerances, the basis 

for AMVAC’s objection, and the proposed relief sought. 

On July 6, 2012, and December 19, 2012, EPA published Federal Register notices proposing, 

and then issuing, a data call-in (DCI) to support the continuation of import tolerances for difenzoquat.3

 

 1 40 C.F.R. § 178.25.

2 78 Fed. Reg. 32155 (May 29, 2013).

3 77 Fed Reg. 39962 (July 6, 2012); 77 Fed. Reg. 75037 (Dec. 19, 2012).
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Notices of intent agreeing to submit the required data were due by March 19, 2013. EPA stated in its May 29, 

2013, notice that it had revoked the tolerances because it had not received any notices of intent to provide the 

requisite data. The tolerances at issue are for residues of difenzoquat on the following commodities: barley, 

cattle, goat, hog, horse, poultry, sheep, and wheat.4

 The effective date of the revocation is the date of the 

order, May 29, 2013. 

EPA states that any commodities that are treated with difenzoquat and that are in the 

channels of trade following the tolerance revocations will not render such food adulterated provided: (1) the 

residue “is present as the result of an application or use of the pesticide at a time and in a manner that was 

lawful under” FIFRA; and (2) the residue “does not exceed the level that was authorized at the time of the 

application or use to be present on the food under a tolerance or exemption from tolerance.”5

 With regard to 

this second criterion, EPA states: “Evidence to show that the food was lawfully treated may include records 

that verify the dates that the pesticide was applied to such food.”6

As noted, the tolerances at issue are “import tolerances” as all difenzoquat registrations 

have been cancelled in the United States. In Canada, difenzoquat products are still registered under the 

Pest Control Product Act. At the time that EPA issued its tolerance revocation order, AMVAC had 

already made its final shipment of difenzoquat product to Canada. Based on discussions with its 

customers in Canada, AMVAC believes that use of registered difenzoquat products is currently 

underway, and that the latest an application from existing stocks will be made is during the 2015 season. 

Since the commodities at issue include barley and wheat, AMVAC is concerned that it 

will be difficult to demonstrate that legally treated commodities are not adulterated. It is AMVAC’s 

understanding that treated grains may be stored for a protracted period and that treated grain might 

also be intermingled with untreated grain while in storage. Given these practical realities, it could be 

difficult, if not impossible, to provide the information concerning the time that these crops were 

treated, which EPA requires as a means of providing evidence that the food was lawfully treated.7

Objection

This objection is filed within the time specified (i.e., before July 29, 2013) and pursuant 

to the regulations set forth at 40 C.F.R. Part 178. AMVAC objects to the order revoking all difenzoquat 

tolerances effective on May 29, 2013, because insufficient time has been afforded to foreign growers 

that continue to rely on these tolerances and because the procedure for demonstrating the time when 

an agricultural commodity was lawfully treated with difenzoquat would be unworkable in practice. EPA 

has stated: “While EPA often proposes to revoke tolerances after the cancellation of associated uses 

because EPA believes the tolerances may no longer be necessary, EPA has always recognized that a 

revocation can not proceed on such grounds if foreign growers wish to rely on the tolerance.”8

 In this 

 4 40 C.F.R. § 180.369.

5 78 Fed. Reg. at 32157.

6 Id.

7 Id.

8 73 Fed. Reg. 64229, 64241 (Oct. 29, 2008).
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case, AMVAC is not objecting to the revocation itself, but asking only that the effective date be extended 

long enough to allow Canadian growers to treat crops legally in Canada and allow those crops to pass 

through the channels of trade. 

EPA states in its May 29, 2013, notice that it “may stay the effectiveness of the 

regulation or order if, after issuance of such regulation or order, objections are filed with respect to such 

regulation or order . . . pursuant to FFDCA section 408(g)(2).”9

 In its June 6, 2013, letter to Richard 

Keigwin of EPA, AMVAC suggested that the tolerances be reinstated until December 31, 2017, to 

accommodate legal Canadian applications of difenzoquat and the distribution of commodities that could 

have difenzoquat residues. It is AMVAC’s understanding that only the wheat and barley tolerances 

would be necessary to remain in effect. AMVAC believes that a decision by EPA to stay the effective 

date of this revocation until that time would be an appropriate measure to allow time for legally treated 

crops like barley and wheat to clear the channels of trade.

AMVAC regrets its oversight of the notices issued prior to May 29, 2013, and its 

consequent failure to provide timely comments. At this juncture, some applications for the 2013 season 

have already been made, and additional applications are expected for future growing seasons in 

compliance with Canadian pesticide laws. AMVAC believes it would be unfair to penalize Canadian 

growers by taking an action that might deny them access to international markets. 

We look forward to working with EPA to resolve this matter. 

Sincerely,

Cindy Baker Smith

Senior VP and Director of Global Regulatory and Product Development

cc: Mr. Richard P. Keigwin, Jr., EPA (via e-mail)

Lisa M. Campbell, Esquire, Bergeson & Campbell, P.C. (via e-mail) 

 9 78 Fed. Reg. at 32156. See also 40 C.F.R. § 178.35 (authorizing EPA to modify the prior tolerance 

revocation order in response to meritorious objections).