[Federal Register Volume 61, Number 42 (Friday, March 1, 1996)]
[Notices]
[Pages 8186-8203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-4963]




[[Page 8185]]

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Part VI





Environmental Protection Agency





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Cyanazine; Notice of Preliminary Determination To Terminate Special 
Review; Notice of Receipt of Requests for Voluntary Cancellation; 
Notice

  Federal Register / Vol. 61, No. 42 / Friday, March 1, 1996 / 
Notices  
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ENVIRONMENTAL PROTECTION AGENCY

[OPP-30000/60A; FRL-5352-6]


Cyanazine; Notice of Preliminary Determination to Terminate 
Special Review; Notice of Receipt of Requests for Voluntary 
Cancellation

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Preliminary Determination to Terminate Special 
Review; Announcement of Receipt of Voluntary Cancellation.

Summary: This Notice sets forth EPA's preliminary determination to 
terminate the Special Review of cyanazine based on amendments to the 
terms and conditions of cyanazine registrations. In effect, the terms 
and conditions call for an incremental phaseout and voluntary 
cancellation of all pesticide products containing cyanazine that are 
registered for use in the United States. The Agency has concluded that, 
based on these terms and conditions of the amended registration of 
cyanazine, any unreasonable adverse effects posed by cyanazine use will 
be eliminated by the phaseout and voluntary cancellation of the 
chemical. The Agency concludes that the benefits of use of the chemical 
for the limited period of time and in strict accordance with all of the 
terms and conditions of registration, outweigh the risks. In making 
this determination, the Agency considered the risks and benefits of 
cyanazine use in the 7-year phaseout, during which maximum label rates 
will be reduced and closed cab application equipment will be required, 
as well as the risks and benefits associated with the ultimate 
cancellation of all use of cyanazine. In addition, pursuant to section 
6(f)(1) of the Federal Insecticide, Fungicide, and Rodenticide Act 
(FIFRA), this Notice announces EPA's receipt of requests to voluntarily 
cancel all registrations containing cyanazine, effective December 31, 
1999.

Dates: Comments, data and information relevant to the Agency's proposed 
decision must be received on or before April 1, 1996.

ADDRESS: Submit three copies of written comments bearing the document 
number [30000/60A]. By mail to: Public Response and Program Resources 
Branch, Field Operations Division (7506C), Office of Pesticide 
Programs, Environmental Protection Agency, 401 M St., SW., Washington, 
DC 20460. In person, bring comments to Room 1132, CM #2, 1921 Jefferson 
Davis Highway, Arlington, VA, Telephone: 703-305-5805.
    Comments and data may also be submitted electronically by sending 
electronic mail (e-mail) to: [email protected]. Electronic 
comments must be submitted as an ASCII file avoiding the use of special 
characters and any form of encryption. Comments and data will also be 
accepted on disks in WordPerfect in 5.1 file format or ASCII file 
format. All comments and data in electronic form must be identified by 
the docket number ``OPP-30000/60A.'' No Confidential Business 
Information (CBI) should be submitted through e-mail. Electronic 
comments on this document may be filed online at many Federal 
Depository Libraries. Additional information on electronic submissions 
can be found in Unit IX. of this document.
    Information submitted as a comment concerning this document may be 
claimed confidential by marking any part or all of that information as 
CBI. Information so marked will not be disclosed except in accordance 
with procedures set forth in 40 CFR part 2. A copy of the comment that 
does not contain CBI must be submitted for inclusion in the public 
record. Information not marked confidential may be disclosed publicly 
by EPA without prior notice. All written comments will be available for 
public inspection in Rm. 1132 at the Virginia address given above from 
8 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: By mail: Joseph E. Bailey, Review 
Manager, Special Review and Reregistration Division (7508W), Office of 
Pesticide Programs, Environmental Protection Agency, 401 M St., SW., 
Washington, DC 20460. Office location, telephone number, and e-mail 
address: Special Review Branch, 3rd Floor, Crystal Station, 2800 
Jefferson Davis Highway, Arlington, VA, Telephone: 703-308-8173, e-
mail: [email protected]. For a copy of documents in the 
public docket, to request information concerning the Special Review, or 
to request indices to the Special Review public docket, contact the 
Public Response and Program Resources Branch, Field Operations Division 
(7506C), Office of Pesticide Programs, Environmental Protection Agency, 
401 M St., SW., Washington, DC 20460, Telephone: 703-305-5805.
Supplementary Information:

I. Introduction

A. Regulatory Background

    Cyanazine is the common name for [2-((4-chloro-6-(ethylamino)-s-
triazine-2-yl)amino)-2-methylpropionitrile], an herbicide sold under 
the tradenames of Bladex and Cynex that is available as a granular or 
liquid formulation. It is classified as a ``Restricted Use Pesticide'' 
based on its reproductive effects and detection in ground and surface 
water. Cyanazine was first registered by Shell Chemical Company in 
1971. Today, DuPont Agricultural Products and Griffin Corporation are 
the only registrants of technical grade cyanazine. Ciba Plant 
Protection also has one registered product, a mixture of cyanazine and 
metalochlor, but submitted a request for voluntary cancellation of this 
product which was announced in the Federal Register of November 8, 1995 
(60 FR 56333) (Ref. 1). A final cancellation order for this product was 
effective February 8, 1996.
    In April 1985, a Special Review of cyanazine was initiated based on 
studies indicating developmental toxicity in two species after oral 
administration of the chemical. The Agency was concerned about 
potential risks to mixer/loaders and applicators exposed to cyanazine. 
Additional dermal developmental toxicity studies that were submitted to 
the Agency led to a refinement of the risk estimates. The Special 
Review was concluded in 1988 by requiring personal protective equipment 
and revised label language.
    The Agency continued to assess ground and surface water monitoring 
data for cyanazine contamination and, to help address contamination 
concerns, approved label amendments in 1993 that reduced maximum 
application rates and required surface water setbacks. These 
amendments, however, did not ameliorate all of the Agency's risk 
concerns and on February 8, 1994, a preliminary notification letter was 
issued to all cyanazine registrants indicating that the Agency was 
considering initiating a Special Review of cyanazine because of 
potential cancer risks from dietary (food and drinking water) and non-
dietary exposure. Additionally, the Agency was also concerned about 
possible ecological risks to nontarget organisms (aquatic organisms, 
terrestrial plants) and their ecosystems that may result from the use 
of cyanazine.
    On November 10, 1994, EPA issued the Notice of Initiation of 
Special Review (Position Document 1 or PD 1) formally announcing that a 
Special Review was being initiated for cyanazine, along with atrazine 
and simazine (58 FR 60412) (Ref. 2). The Agency formally initiated the 
Special Review based only on the cancer risk concern to humans. The 
Agency remains concerned about possible 

[[Page 8187]]
ecological effects; however, these effects were not considered as 
formal criteria to initiate the Special Review.
    On August 2, 1995, DuPont voluntarily proposed to amend its 
cyanazine registrations to effectively phaseout the production of 
cyanazine for use in the U.S. by the end of 1999, with incremental 
reductions in maximum label application rates in 1997, 1998, and 1999 
and a closed cab requirement for applicators beginning in 1998 (Ref. 
3). Cyanazine products that have been released for shipment by a 
registrant on or before December 31, 1999, may only be distributed and 
sold in the channels of trade in accordance with their labels through 
September 30, 2002. Such products may only be used through December 31, 
2002. EPA accepted DuPont's proposal to amend its cyanazine 
registrations. Since the acceptance of DuPont's proposal to amend 
cyanazine registrations, EPA has granted new conditional cyanazine 
registrations to Griffin based on Griffin's agreement to accept the 
same terms and conditions as part of its cyanazine registrations (Refs. 
4, 5, 6, 7, and 8).
    The Agency has evaluated the risks and benefits posed by the terms 
and conditions of the phaseout and voluntary cancellations submitted by 
the manufacturers of cyanazine and approved by EPA. Among the factors 
considered were the risks of use during and after the phaseout period 
and arising from use of existing stocks, the benefits that will accrue 
from use during the phaseout and use of existing stocks, the incentives 
for and likelihood of the development of alternative control strategies 
of a phaseout as opposed to an immediate commencement of cancellation 
proceedings, and the litigative risks and uncertainties attendant to a 
contested regulatory action as opposed to a voluntary action. Taking 
all of these factors into consideration, the Agency has concluded that 
risks associated with the proposed voluntary phaseout and cancellation 
are outweighed by its benefits. Accordingly, the Agency believes the 
Special Review of cyanazine may be terminated on the basis of the 
voluntary cancellation.
    In response to the triazine PD 1 issued in November 1994, the 
Agency received a number of comments about the risks and benefits of 
cyanazine. All of the issues raised in the cyanazine comments received 
during the comment period are addressed in this Notice and are on file 
in the triazine public docket (OPP-30000/60). While a number of the 
comments challenged the Agency's decision to initiate the Special 
Review of the triazines and questioned various components of the 
Agency's assessments, no additional scientific data were received by 
the Agency that change the Agency's previous conclusions about 
potential risks from cyanazine exposure. The majority of the comments 
received were undocumented testimonials that generally made claims 
concerning the usefulness of cyanazine. A few commenters provided 
additional ground and surface water monitoring data. All of the 
comments relating to cyanazine benefits have been considered in 
assessing the economic impacts of phasing out cyanazine. Similarly, all 
of the comments relating to cyanazine risks have been considered in 
assessing the risks associated with the phaseout of cyanazine. 
Significant comments and the Agency's responses to the comments are 
discussed in appropriate sections of this Notice. Supporting 
documentation may be found in the cyanazine public docket (OPP-30000/
60).
    As discussed above, the Agency has recently granted cyanazine 
conditional registrations to Griffin Corporation. These recently-
approved cyanazine registrations, as well as any others that may be 
granted by the Agency in the future, are required to comply with all of 
the same terms and conditions of registration for cyanazine as approved 
by the Agency for DuPont's registrations. The Griffin products were 
conditionally registered by the Agency provided that Griffin comply 
with all of the same terms and conditions of the DuPont cyanazine 
registrations. If Griffin does not comply with the same terms and 
conditions of the cyanazine registration, its registrations are subject 
to cancellation by the Agency in accordance with FIFRA section 6(e). 
Griffin's release for shipment of its products containing cyanazine 
constitutes acceptance of the terms and conditions of the 
registrations. In accordance with FIFRA section 3(c)(7)(A), these 
conditional registrations have been approved because the Agency has 
determined that they are substantially similar to other currently 
registered cyanazine products or differ only in ways that do not 
significantly increase the risk of unreasonable adverse effects to the 
environment.

B. Legal Background

    In order to obtain a registration for a pesticide under FIFRA, an 
applicant must demonstrate that the pesticide satisfies the statutory 
standard for registration. The standard requires, among other things, 
that the pesticide will not cause ``unreasonable adverse effects on the 
environment'' [FIFRA section 3(c)(5)]. The term ``unreasonable adverse 
effects on the environment'' means ``any unreasonable risk to humans or 
the environment, taking into account the economic, social, and 
environmental costs and benefits of the use of any pesticide'' [FIFRA 
section 2(bb)]. This standard requires a finding that the benefits of 
each use of the pesticide outweigh the risks of such use, when the 
pesticide is used in compliance with the terms and conditions of 
registration and in accordance with commonly recognized practices.
    The burden of proving that a pesticide satisfies the statutory 
standard is on the proponents of registration and continues as long as 
the registration remains in effect. Under FIFRA section 6, the 
Administrator may cancel the registration of a pesticide or require 
modification of the terms and conditions of a registration if the 
Administrator determines that the pesticide product causes unreasonable 
adverse effects to man or the environment. EPA created the Special 
Review process to facilitate the identification of pesticide uses that 
may not satisfy the statutory standard for registration and to provide 
a public procedure to gather and evaluate information about the risks 
and benefits of these uses.
    A Special Review may be initiated if a pesticide meets or exceeds 
the risk criteria set out in the regulations at 40 CFR part 154. When 
EPA believes that a pesticide has met such risk criteria, a notice is 
published in the Federal Register which announces the initiation of the 
Special Review. After a PD 1 is issued, registrants and other 
interested persons are invited to review the data upon which the review 
is based and to submit data and information to rebut EPA's conclusions 
by showing that EPA's initial determination was in error, or by showing 
that use of the pesticide is not likely to result in unreasonable 
adverse effects on human health or the environment. In addition to 
submitting rebuttal evidence, commenters may submit relevant 
information to support EPA's initial conclusions or to aid in the 
determination of whether the economic, social and environmental 
benefits of the use of the pesticide outweigh the risks. After 
reviewing the comments received and other relevant materials obtained 
during the Special Review process, EPA makes a proposed decision on the 
future status of registrations of the pesticide.
    The Special Review process may be concluded in various ways 
depending upon the outcome of EPA's risk/benefit assessment. If EPA 
concludes that all of its risk concerns have been adequately 

[[Page 8188]]
rebutted, the pesticide registration will be maintained unchanged. If, 
however, all risk concerns are not rebutted, then EPA will proceed to 
assess risks and benefits. EPA considers possible changes to the terms 
and conditions of registration that can reduce risks to a level that 
satisfies the risk criteria used to initiate Special Review. If risks 
can be reduced to the level, then the Agency considers whether the 
benefits outweigh those risks. Based upon this analysis, it may require 
that such changes be made in the terms and conditions of the 
registration. Alternatively, EPA may determine that no changes in the 
terms and conditions of a registration will adequately assure that use 
of the pesticide will not cause any unreasonable adverse effects. If 
EPA makes such a determination, it may seek cancellation, suspension, 
or change in classification of the pesticide's registration. This 
determination would be set forth in a Notice of Final Determination 
issued in accordance with 40 CFR 154.33.
    When the Administrator proposes to cancel, deny, or change the 
classification of the registration of a pesticide product which is the 
subject of a Special Review, regulations at 40 CFR 154.31(b) require 
that the Agency submit notices of preliminary determination to the 
Secretary of Agriculture and the Scientific Advisory Panel for review 
and comment. In the case of the proposed decision for cyanazine, the 
Agency does not deem this necessary because the cancellation of all 
cyanazine products is a voluntary action on behalf of the registrants.
    Issuance of this Notice means that the Agency has assessed the 
potential adverse effects of cyanazine and has preliminarily determined 
that continued, but limited, use of the pesticide under the agreed-upon 
terms and conditions of cyanazine registration with DuPont and Griffin 
will not present unreasonable adverse effects when considering: (1) 
Risks and benefits of restricted, continued use of cyanazine through 
the phaseout period and (2) the ultimate cancellation of all cyanazine 
registrations. The Agency is proposing to terminate the Special Review 
of cyanazine based on the fact that use will be restricted during the 
phaseout period and no cyanazine use will be allowed after December 31, 
2002, and, therefore, continuation of the Special Review is no longer 
necessary. Included as part of the terms and conditions of cyanazine 
registration are cyanazine registrants' waivers of rights to challenge 
the Agency's final action on the cyanazine Special Review or the terms 
and conditions of registration, including label amendments, required by 
agreements in any court or administrative forum. The complete terms and 
conditions that amend cyanazine registration are provided in Unit X. of 
this Notice.

II. Summary of Toxicological Concerns

A. Carcinogenicity

    The initiation of the Special Review of cyanazine in 1994 was based 
on evidence that cyanazine may cause cancer in persons exposed to the 
chemical through their diet (food and drinking water) and through 
exposure while handling the chemical (mixer/loaders and applicators). 
This risk concern is based on a statistically-significant incidence of 
malignant mammary gland tumors in female Sprague-Dawley rats that were 
exposed to cyanazine through their diet for 2 years. In addition to the 
mammary gland tumors observed in these rats, the weight-of-the-evidence 
for the carcinogenic potential of cyanazine includes the evidence that 
cyanazine is structurally related to the other chloro-s-triazines which 
also induce mammary gland cancer in female Sprague-Dawley rats. 
Although cyanazine is structurally related to the other chloro-s-
triazines, cyanazine differs in that it contains a cyano (nitrile) 
functional group that is highly reactive.
    In March 1991, the OPP Carcinogenicity Peer Review Committee 
evaluated the weight-of-the-evidence for cyanazine, with particular 
emphasis on its carcinogenic potential. The Peer Review Committee 
concluded that cyanazine should be classified as a Group C, possible 
human carcinogen, and recommended quantification of human risk using a 
linearized multi-stage model to extrapolate from effects seen at high 
doses in laboratory studies to predict tumor response at low doses. 
Using this model, the cancer potency equivalent (Q1*) for 
cyanazine is 1.0 x 100 (mg/kg/day)-1 based on the development 
of mammary gland adenocarcinomas and carcinosarcomas in female rats. 
This represents the 95 percent upper confidence limit of tumor 
induction likely to occur from a unit dose. The cancer classification 
of cyanazine has not been presented to the FIFRA Scientific Advisory 
Panel (SAP) for review.
    A more detailed discussion about the evidence that cyanazine may 
cause cancer can be found in the PD 1.

B. Comments Regarding the Carcinogenicity of Cyanazine and the Agency's 
Response

Comment: DuPont Agricultural Products and Griffin Corporation responded 
that the Agency does not have sufficient toxicological evidence to 
support its position that cyanazine may pose a cancer risk to humans. 
Both state that the Sprague-Dawley rat model is inappropriate and that 
evidence supports their assertion that cyanazine tumorigenicity is 
associated with a hormonally-mediated threshold effect.
Agency Response: In the PD 1 for atrazine, simazine, and cyanazine, the 
Agency considered all information available at that time to evaluate 
the carcinogenic potential of the triazines, including the 
appropriateness of the Sprague-Dawley rat model, the method of 
quantifying the carcinogenic risk and DuPont's assertion that cyanazine 
tumorigenicity occurs through a hormonal mechanism. In response to the 
PD 1, the Agency received additional information with comments 
submitted for atrazine and simazine that will be reviewed and evaluated 
in the continuing Special Review of those chemicals. The Agency 
received no new information, however, to dispute the carcinogenicity 
classification for cyanazine. Currently, it is the Agency's policy to 
regulate carcinogens based on risk assessment procedures that utilize 
the Q1* approach in the absence of data to support the 
hypothesis of hormonally-mediated threshold responses. On several 
occasions, DuPont has indicated that they have undertaken research that 
will attempt to validate a hormonally-mediated mechanism of 
carcinogenicity; however, the Agency received no information from 
DuPont that attempts to prove such a mechanism exists.
Comment: DuPont does not believe that a link between breast cancer and 
exposure to cyanazine exists and has stated that reviews of several 
epidemiology studies on estrogen replacement therapy find no such link.
Agency Response: When the Agency initiated the Special Review for the 
triazines, it had not concluded that cyanazine was directly related to 
an incidence of human breast cancer. Upon review of published 
literature, the Agency indicated that such tumor development in humans 
seemed possible and that during the course of the Special Review, 
further research into epidemiological studies would hopefully provide 
information to make rational decisions about such cause and effect 
relationships. The Agency is not in a position at this point to draw 
any 

[[Page 8189]]
definitive conclusions about human breast cancer and cyanazine; 
however, the Agency will continue to consider information throughout 
the Special Review of the other triazines that may help clarify whether 
an association exists. Information in published literature support the 
possibility that some link between breast cancer and the triazine 
herbicides is possible.
Comment: The National Coalition Against the Misuse of Pesticides 
(NCAMP) provided comments about the triazines in general without 
reference to cyanazine specifically. NCAMP supports the Agency's 
Special Review of the triazines but unequivocally states that the 
Agency must cancel the triazines due to unreasonable cancer risks.
Agency Response: The terms and conditions of DuPont and Griffin 
cyanazine registrations now provide for voluntary cancellation of all 
cyanazine registrations in 1999 and will eventually result in a total 
phaseout of the use of cyanazine in the U.S. During the period of the 
phaseout, the Agency estimates that the risks will be decreasing 
because of the reductions in allowable maximum application rates and 
the requirement that applicators must work in closed cabs. Taking the 
cyanazine phaseout and voluntary cancellation into consideration, the 
Agency has evaluated the risks and benefits of cyanazine and determined 
that the terms and conditions of the phaseout and voluntary 
cancellations, as submitted by the manufacturers and approved by EPA, 
will ultimately eliminate any unreasonable adverse effects associated 
with the use of cyanazine. Accordingly, the Agency is proposing to 
terminate the Special Review. As with all Special Reviews, cancellation 
of uses is an available option but is only imposed when other less 
severe risk reduction measures are not adequate to eliminate 
unreasonable adverse effects.
Comment: NCAMP commented that evidence supports the classification of 
all of the triazines as Group B carcinogens.
Agency Response: The Agency has taken its decision about the cancer 
classification of atrazine and simazine to the SAP on a number of 
occasions. The SAP agreed with the Agency's cancer classification of 
atrazine and simazine. Current weight-of-the-evidence for cyanazine 
supports its classification as a Group C carcinogen. Further, NCAMP did 
not provide any additional data or evidence to support their assertion. 
Accordingly, the Agency has concluded that cyanazine is a class C 
carcinogen. The Agency has not presented the cancer classification of 
cyanazine to the SAP, and in light of the cyanazine phaseout and the 
ultimate cancellation of this chemical, does not believe that it is 
necessary to do so.
Comment: In general, Griffin commented that the Agency failed to 
provide adequate information to allow others to fully evaluate its risk 
assessments.
Agency Response: As required by the regulations governing Special 
Review procedures, the Agency has provided a record of all background 
documents used in its assessments through the public docket. The public 
docket contains all supporting documentation that describes all of the 
assumptions and values used by the Agency to conduct the risk 
assessments. The Agency has made available the same level of 
information for the cyanazine Special Review as it has for other 
Special Reviews, and this information should be adequate to evaluate 
the assessments.

III. Summary of Exposure and Related Human Health Risks

    In the PD 1, the Agency provided upper bound estimates of 
carcinogenic risks from dietary exposure from both food and drinking 
water and occupational exposure to handlers (mixer/loader/applicators) 
of cyanazine.

A. Dietary Exposure and Associated Risks

    Dietary exposure to cyanazine can occur through the direct 
consumption of cyanazine residues in treated food as well as from 
commodities that contain secondary residues from animals that were fed 
cyanazine-treated crops. In the PD 1, the Agency considered all 
residues (per its equivalency policy), including parent cyanazine and 
both chloro and hydroxy metabolites, to be of toxicological concern. 
Anticipated residues were calculated using data from field trials, 
processing studies, and metabolism studies.
    The total upper bound dietary risk estimate from exposure to 
cyanazine residues in food, as reported in the PD 1, is 2.9 x 10-
5. This estimate did contain a risk contribution from wheat and 
sorghum, uses which have been voluntarily cancelled and thus removed 
from cyanazine labels. Removing the risk contribution for wheat and 
sorghum from the total decreases the total upper bound risk to 2.7 x 
10-5. The Agency has not received any data that justifies the 
revision of any of the assumptions used in its dietary risk assessment 
other than the information with respect to the voluntary cancellation 
of the wheat and sorghum uses. For a detailed discussion of those 
assumptions, the reader is referred to the PD 1. Table 1 below provides 
the dietary risk estimates as discussed in the PD 1.

                              Table 1.--Dietary Cancer Risk Estimates for Cyanazine                             
----------------------------------------------------------------------------------------------------------------
                                      Anticipated        Percent Crop      Exposure (mg/kg/   Upper Bound Cancer
            Commodity                Residue (ppm)          Treated              day)           Risk Estimates  
----------------------------------------------------------------------------------------------------------------
Corn                              0.12                20                  1.2 x 10-5          1.2 x 10-5        
                                                                                                                
Cottonseed                        0.09                5                   9.3 x 10-8          9.3 x 10-8        
                                                                                                                
Milk                              0.00028 (milk)      --                  1.2 x 10-6          1.2 x 10-6        
                                  0.000034 (non-fat                                                             
                                   solids)                                                                      
                                                                                                                
Poultry and eggs                  0.00232             --                  3.1 x 10-6          3.1 x 10-6        
                                  0.004322                                                                      
                                                                                                                
Red meat                          0.00345             --                  1.0 x 10-5          1.0 x 10-5        
                                  0.01031                                                                       
                                                                                                                
Sorghum                           0.10                5                   1.2 x 10-7          1.2 x 10-7        
                                                                                                                
Wheat                             0.16                1                   2.3 x 10-6          2.3 x 10-6        
                                                                                                                
Total                                                                                         2.9 x 10-5        
Total excluding wheat and                                                                     2.7 x 10-5        
 sorghum                                                                                                        
----------------------------------------------------------------------------------------------------------------

    1Range of values were used for meat, meat byproducts, fat, 
liver, and kidney.
    2Range of values were used for meat, meat byproducts, fat, 
liver, kidney and eggs.

[[Page 8190]]

B. Comments Regarding Cyanazine Dietary Risk Estimates and the Agency's 
Response
Comment: Griffin contends that Anticipated Residue (AR) values used by 
EPA were not identified and interpolation of EPA's calculations reveals 
that values used are exaggerated and inappropriate for determining 
actual dietary risks. Griffin further objects to the Agency's use of 
translated data from cattle to estimate anticipated residues in other 
animal commodities. DuPont disagreed with the extrapolation from 
metabolism studies to estimate residues in meat, milk, and eggs and the 
assumption that 100 percent of the livestock feed from corn, cotton, 
wheat, and sorghum has been treated with cyanazine.
Agency Response: The AR values used in the Agency's risk assessment are 
listed in Table 1 above and were identified in the PD 1 as well as in 
the supporting documentation that was in the public docket at the time 
of publication of the PD 1. In completing the dietary risk assessment 
for cyanazine, the Agency utilized its standard approach to estimate AR 
values and then used those values in determining dietary exposure 
estimates and carcinogenic risk through its Dietary Risk Evaluation 
System (DRES). Documentation supporting the estimation of ARs and 
dietary exposure values is contained in the references used for the 
triazine PD 1 and can be found in the triazine public docket. To 
determine the cyanazine AR values for risk assessment purposes for crop 
commodities, the Agency averaged the actual residues detected in field 
trials; for nondetectable residues, the Agency assumed the residue 
level equalled one-half of the analytical method's limit of detection. 
This approach precludes the possibility of overestimating or 
underestimating risks that could otherwise be based on residue values 
at high or low detections. To estimate the ARs for animal commodities, 
the Agency used animal dietary burden data which take into 
consideration anticipated residues on feed crops as well as percent 
crop treated data and animal metabolism studies. Since the consumption 
of feed by animals has already been adjusted to account for the percent 
of the crop that has been treated with cyanazine, use of the 100 
percent assumption is appropriate.
    The Agency routinely translates data between commodities with 
sufficient similarities, such as translating apple data to pears. 
Translation is performed when data are either not available or are 
insufficient. In the case of cyanazine, crop data do exist. Data for 
cattle and other ruminants can be translated only to other animals such 
as goats, sheep, hogs or horses, but not to poultry. Ruminant data 
exist for cyanazine and were used to estimate risks in the PD 1. 
However, at the time the PD 1 was published, cyanazine poultry 
metabolism data were not available. Therefore, atrazine poultry 
metabolism data were translated to cyanazine. Since atrazine and 
cyanazine were grouped for Special Review purposes due to their 
structural and metabolic similarities, the Agency considered it to be 
appropriate to bridge this data gap by translation. Griffin did not 
provide an alternative risk assessment for the Agency to review or any 
additional data for review and consideration in refining risk 
estimates.
Comment: Griffin stated that the Agency's use of information from the 
1977 - 1978 National Food Consumption Survey to estimate consumption 
values is inappropriate because food consumption patterns have changed 
dramatically over the past 17 years; therefore, ingestion rates used in 
the dietary risk assessment are invalid. Griffin also stated that the 
source of the percent crop treated data was not provided.
Agency Response: Although Griffin did not agree with the Agency's use 
of the 1977 - 1978 information to predict ingestion rates, it provided 
no data that the Agency could use to revise the consumption values. The 
Agency acknowledges that the 1977 - 1978 National Food Consumption 
Survey may not reflect the most current consumption profile of 
individuals in the United States. The continuing surveys of food intake 
by individuals were performed in 1989 through 1991; the Agency is 
working to translate these data into a form useful for the Agency's 
Dietary Risk Evaluation System. However, until these data are in a 
useable form, the Agency will continue to use the 1977 - 1978 data.
    The Agency revised the percent crop treated data for cyanazine in 
1994 using the most current United States Department of Agriculture 
(USDA) and other proprietary usage estimates that were available at 
that time. The data reflect annual fluctuations in use patterns as well 
as variability as a consequence of using data from various information 
sources. Griffin did not supply any percent crop treated data for the 
Agency to evaluate.
Comment: Griffin asserts that EPA calculations incorrectly assume that 
all secondary sources of ingested cyanazine are contaminated with 100 
percent of the AR level.
Agency Response: The Agency does use 100 percent of the AR level in its 
calculations to estimate dietary risk; however, as discussed above, the 
AR value has taken factors into consideration to adjust for the fact 
that 100 percent of a crop may not be treated with the chemical. 
Therefore, further percent crop treated adjustments are not necessary 
and would tend to underestimate potential risks.
Comment: Griffin purports that EPA provided no specific information 
about the exposure frequency and exposure duration values used in its 
calculations; i.e., EPA assumes that an individual consumes a maximum 
amount of a particular food all in the same day, every day, for an 
entire lifetime and does not account for differences in exposure 
duration for people living in urban areas, rural areas and farms.
Agency Response: The Agency acknowledges that there are differences in 
food consumption habits across the U.S. To estimate chronic dietary 
risk, the Agency considered information it has on the general U.S. 
population as well as 22 population subgroups. The Agency's Dietary 
Risk Evaluation System utilizes information that was obtained from the 
1977 - 1978 food consumption survey discussed above. This survey was 
designed to statistically encompass all income levels and all 
population areas of the U.S., including participants from both rural 
and urban areas. Average dietary consumption of an individual over a 3-
day period is determined. The consumption value is then matched to the 
self-reported body weight of the individual. All data for both 
consumers and non-consumers of a particular commodity are then combined 
or averaged to determine dietary exposure. Currently, this survey 
provides the best estimate of food consumption patterns in the U.S., 
assuming average consumption over a 70-year lifetime.
Comment: Griffin contends that EPA provided no information indicating 
the values used for body weight assumptions.
Agency Response: Details about the assumptions used in the DRES 
calculations were provided in the public docket. To calculate dietary 
risk estimates for food and drinking water consumption, the Agency has 
used information that was obtained in the 1977 - 1978 food consumption 
survey. This survey matched individual consumption with individual 
reported body weights of the respondents and the information is then 
used by the Dietary Risk Evaluation System to estimate risk. Therefore, 
the Agency has used the self-reported body weights to calculate both 
the dietary and drinking water risk estimates. The self-reported body 

[[Page 8191]]
weights average out to approximately 58 kg.
Comment: DuPont states that, because the use of cyanazine on sorghum 
and wheat was voluntarily canceled, risks from these sources should be 
removed from the risk assessment calculations.
Agency Response: The Agency accepted DuPont's request to voluntarily 
cancel cyanazine use on wheat and sorghum. The Agency has removed the 
risk contribution from use on wheat and sorghum from the dietary risk 
assessment. The upper bound dietary risk estimate without the 
contribution from wheat and sorghum is 2.7 x 10-5 which is still 
considered to be unacceptable.
Comment: DuPont commented that EPA has presented upper bound risk 
estimates only and ignored the most likely estimates which would be 
orders of magnitude lower.
Agency Response: It is standard policy for the Agency to provide upper 
bound carcinogenic risk estimates. The use of less than upper bound 
risk estimates may not adequately account for risks to the most 
sensitive populations such as infants, children, or the elderly. The 
Agency acknowledges that the true risk estimates may be as low as zero 
for some people in some risk scenarios; i.e. where no exposure is 
present.
Comment: DuPont stated that EPA should not make the assumption that 
chloro and hydroxy metabolites of cyanazine are as toxic as the parent 
chemical.
Agency Response: In the absence of appropriate toxicological 
information, it is the Agency's policy to use a default assumption that 
metabolites are no more or no less toxic than the parent compound. The 
Agency is not aware of any information that indicates that cyanazine 
metabolites are less toxic than cyanazine itself. The Agency has 
completed its review of the hydroxyatrazine study and is currently 
determining the study's impact on atrazine and simazine anticipated 
residue calculations. The Agency has decided that translation of the 
results of this study to simazine is appropriate. However, because the 
structure of cyanazine contains the cyano functional group and the 
other two triazines in Special Review do not, the Agency has decided 
that it would not be appropriate to translate results of the 
hydroxyatrazine study to cyanazine.

C. Drinking Water Exposure and Associated Risks

    Ground and surface water sources provide drinking water for human 
consumption. While the Agency does not yet have an enforceable 
regulatory standard or Maximum Contaminant Level (MCL) for cyanazine 
contamination of drinking water, a lifetime Health Advisory Level (HAL) 
has been established at 1.0 g/L. Information from a number of 
ground and surface water monitoring studies has indicated that 
cyanazine detections are frequently found, especially in surface 
waters.
    To prepare the PD 1, the Agency considered information from a 
number of surface water monitoring studies that indicated the presence 
of cyanazine in areas of the Midwest where it is frequently used. The 
information from these studies indicates that cyanazine is detected in 
many streams and rivers for several months post-application at 
concentrations of at least several g/L due to runoff. However, 
the percentage of detections is lower during early spring (pre-
application) and during fall and winter, many months after application. 
Concentrations are usually less than 1.0 g/L. There are 
reports of cyanazine detections in some lakes and reservoirs that 
remain constant at several g/L almost year round. The ground 
and surface water monitoring studies that provide evidence of cyanazine 
contamination of water supplies are discussed in the PD 1.
    The Agency based its drinking water risk concerns on the cyanazine 
detections discussed above and calculated high end (90th percentile) as 
well as risk estimates for mean consumption of cyanazine-contaminated 
drinking water derived from both ground and surface water sources. In 
the PD 1, the Agency's estimates from exposure to a mean concentration 
of cyanazine in ground and surface water are 2.3 x 10-6 and 9.7 x 
10-6, respectively. The upper bound risk estimates from a 90th 
percentile exposure in ground and surface water are 4.0 x 10-6 and 
6.6 x 10-5, respectively. These risk estimates may underestimate 
the actual risk because they are based on exposure to cyanazine parent 
compound only and do not include the potential contribution to risk 
from cyanazine degradates. The Agency is also concerned about exposure 
to cyanazine degradates that are assumed to be no more or less toxic 
than the parent compound. It is important to note that the cyanazine 
drinking water risk estimates are representative values for individuals 
residing in the corn belt region where the chemical is used and do not 
apply to the entire U.S. population, particularly areas where the 
chemical is not used. Details about the Agency's drinking water 
assessments for ground and surface water may be found in the PD 1. 
Since the publication of the PD 1, the Agency has not received any 
information that would significantly alter the cyanazine risk 
estimates. Table 2 below shows the drinking water risk estimates as 
provided in the PD 1.

     Table 2.--Excess Individual Lifetime Cancer Risk Estimates from    
     Consumption of Cyanazine-Contaminated Surface and Ground Water     
------------------------------------------------------------------------
                                     Mean Exposure      90th Percentile 
------------------------------------------------------------------------
Cyanazine - surface water         9.7 x 10-6          6.6 x 10-5        
Cyanazine - ground water          2.3 x 10-6          4.0 x 10-6        
------------------------------------------------------------------------

D. Comments Regarding Cyanazine Drinking Water Risk Estimates and the 
Agency's Response

Comment: DuPont and Griffin contend that data from ground water 
monitoring programs conclusively demonstrate that cyanazine ground 
water detections are either nonexistent or extremely low. Neither EPA's 
modeling nor actual ground water survey data support any regulatory 
action to alter cyanazine registration status. DuPont and Griffin 
specifically noted that studies cited in the PD 1 do not support the 
claim that ground water contamination with cyanazine is a concern.
Agency Response: The Agency continues to believe that cyanazine 
contamination of ground water supplies poses concerns. Griffin was 
correct in stating that cyanazine was not detected in EPA's National 
Survey of Pesticides in Drinking Water Wells. However, the detection 
limit in the survey was 2.4 g/L whereas the Agency's HAL for 
cyanazine is 1.0 g/L. It is quite possible that there were 
undetected residues of cyanazine at or greater than the HAL but less 
than the detection limit. The fact that cyanazine was detected in few 

[[Page 8192]]
wells in the Monsanto National Alachlor Well Water Survey is reasonable 
because the survey focused on the alachlor use area. The Agency does 
not believe that the use of cyanazine geographically coincides closely 
enough with the use of alachlor to rely heavily on the results of this 
study to be representative of the contamination potential of cyanazine. 
For example, in Illinois, only a small percentage of the total corn 
acreage is treated with both alachlor and cyanazine. Most alachlor 
applications are accompanied by treatments with atrazine, dicamba, or 
glyphosate. Therefore, it would be less likely to detect cyanazine in 
alachlor use areas. Also, no degradates were analyzed for in the 
survey. Griffin further stated that no cyanazine was detected in ground 
water during retrospective studies conducted by Shell. Although the 
wells were located near fields in which corn had been grown in the last 
5 years, in areas where 60 - 69 percent of the wells were tested, 
cyanazine was not used or usage could not be confirmed in the 
associated corn field. Therefore, these studies do not represent the 
most accurate impact of cyanazine use on ground water quality. 
Cyanazine was detected in 155 of 7,468 wells as noted in EPA's 
Pesticides in Ground Water Database. The cyanazine detections in the 
wells of 14 states probably resulted from nonpoint source mechanisms.
    The Agency acknowledges that the parent cyanazine compound may not 
be very persistent under most field conditions; however, total chloro-
degradate residues of cyanazine are potentially very persistent 
depending on environmental conditions such as those that may be found 
in ground water reservoirs. The Agency also acknowledges that less 
information is available about the contamination of ground water with 
cyanazine than with atrazine simply because cyanazine has not been as 
extensively researched as atrazine. However, the information that the 
Agency does have about the fate characteristics of cyanazine, the 
monitoring data, and the large amounts of cyanazine that are used 
continues to support the Agency's concern for ground water 
contamination.
Comment: DuPont stated that the Agency has no information indicating 
that cyanazine metabolites will reach ground water in concentrations of 
toxicological concern.
Agency Response: The Agency has limited data on the detection of 
cyanazine degradates in ground water; however, cyanazine is 
structurally similar to atrazine and simazine and has similar 
environmental fate characteristics with some common degradates. Because 
of the similarity in fate characteristics, the Agency believes that it 
is reasonable to assume that cyanazine degradates may reach ground 
water supplies. Both atrazine and cyanazine degrade to deisopropyl 
atrazine, a chlorodegradate that the Agency assumes to be no more or 
less toxic than the parent compound.
Comment: Griffin commented that EPA's use of CHEMRANK and LEACH models 
overestimates cyanazine's leaching potential.
Agency Response: The Agency believes that the models used are helpful 
in judging whether significant differences exist in the leaching 
potential between different pesticides but are not truly predictive of 
the amounts of pesticides that will leach to ground water at a 
particular site. In addition, the screening models used do not take 
degradates into account; one particular cyanazine degradate, 
deisopropyl atrazine, is extremely mobile and has been widely found in 
ground water. So, the models may in fact underestimate risk.
Comment: The South Dakota and Minnesota Departments of Agriculture and 
the Illinois Environmental Protection Agency submitted surface water 
monitoring data in response to the PD 1 that included information for 
cyanazine.
Agency Response: The Agency has considered the data submitted by each 
of these commenters. The South Dakota and Minnesota data were 
consistent with United States Geological Survey (USGS) 1989 and 1990 
reconnaissance studies of the Midwestern corn belt that showed levels 
of cyanazine in the surface waters of those states generally to be 
substantially lower than in several other states such as Illinois, Iowa 
and Ohio. Although the available data are not sufficient to conclude 
with certainty that cyanazine is not a potential problem in either 
state, the Agency's primary concerns were and remain at this time with 
some of the other corn belt states. For example, arithmetic average 
annual cyanazine concentrations for samples collected from West Lake, 
IA, exceeded the HAL in 1992 and 1993, and for samples collected from 
Rathbun Reservoir, IA, exceeded the HAL in 1992 and 1994. Although 
these averages are arithmetic and are only of detects, the Agency 
believes in this case that the arithmetic averages are relatively close 
to time-weighted mean concentrations because of the regularity of the 
sampling dates. Such regularity would not be observed if there were a 
significant number of non-detects or if the sampling schedule was 
skewed. Additionally, the Agency received raw data from the 
Environmental Working Group in which 29 surface water supplies were 
monitored for cyanazine biweekly from March, April or May through 
August 1995. Using these data, the Agency calculated time-weighted mean 
concentrations. Six of the 29 systems sampled had cyanazine estimated 
time-weighted mean concentrations greater than the HAL of 1.0 
g/L (Bowling Green, OH - 1.4 g/L; Columbus, OH - 1.04 
g/L; Danville, IL - 2.47 g/L; Decatur, IL - 1.88 
g/L; Johnson County, KS - 1.01 g/L; and Springfield, 
IL - 3.07 g/L) (Ref 6).
    In response to the PD 1, the Illinois Environmental Protection 
Agency submitted data to update their network of 30 raw surface water 
sampling sites from the Moyer and Cross report that covered 1985 - 1988 
to include 1989 - 1993. Also provided were data on cyanazine 
concentrations in finished water samples collected quarterly from 
September 1992, to June 1994, from numerous surface water source 
supplies throughout the state. Although the data updating the 30 raw 
water sampling stations is in summary form with only mean 
concentrations provided for the entire sampling period (1985 - 1993) 
given for each site, the reported cyanazine average concentrations 
equaled or exceeded the HAL at 7 of the 30 sites and equaled or 
exceeded 3 g/L at 2 of those sites, even with the damping 
effect associated with long-term multiple year averaging. Although the 
arithmetic averages may be somewhat greater than time-weighted mean 
concentrations, the Agency believes that they are probably not that 
much greater due to the general collection of samples pre-application 
and during the fall as well as a small number post-application. The 
data further support the Agency's position that cyanazine detections in 
the surface waters of Illinois remain of concern.
Comment: Griffin and DuPont commented that detections of cyanazine in 
surface water fluctuate seasonally with detections peaking in spring 
and summer but returning to background levels that do not present 
health concerns for the majority of the year. DuPont believes that 
studies on effectiveness of best management practices (BMP) provide 
evidence that DuPont's BMP efforts have helped reduce surface water 
levels.
Agency Response: The Agency agrees that cyanazine detections tend to be 
seasonal; however, the detections that are reported remain as a concern 
to the Agency. Monitoring data post 1990 from West Lake and Rathbun 
Reservoir in 

[[Page 8193]]
Iowa, as well as data provided to the Agency by the Environmental 
Working Group and the Illinois Environmental Protection Agency, support 
the Agency's concern that average annual cyanazine concentrations in 
some surface source drinking water supplies continue to exceed the HAL 
of 1 g/L. Data from studies conducted by Baker in Ohio and the 
USGS in the Midwestern corn belt show that maximum cyanazine 
concentrations exceed the HAL and that such concentrations may last 
several weeks post-application. The Agency agrees with DuPont's 
statement that concentrations of cyanazine exceeding 10 g/L 
are more likely to occur in small streams rather than larger streams 
and rivers where the concentration is likely to be diluted. DuPont's 
assertion that small streams do not generally supply drinking water is 
true. However, cyanazine concentrations often remain elevated for 
longer periods of time in larger streams and rivers due to cyanazine 
loadings that occur at different times within the watershed upstream 
from the sampling location. Also, cyanazine concentrations appear to 
remain elevated longer in lakes and reservoirs such as West Lake and 
Rathbun Reservoir due to lower microbiological activities coupled with 
long hydrological residence times. In the USGS reconnaissance survey of 
129 surface water sites within the Midwestern corn belt, greater than 
10 percent of the sites had post-application concentrations of 
cyanazine greater than 10 g/L; in the study by Baker of eight 
tributaries of Lake Erie over 4 years (32 site-years), 19 percent had 
maximum concentrations exceeding 10 g/L.
    The Agency does believe that the changes brought about by the 
adoption of the BMPs has helped to decrease the triazine loading of 
surface waters. The Agency believes that the reduction in use rates 
called for during the phaseout of cyanazine will further help reduce 
the loading to surface waters from agricultural runoff. However, the 
decreases observed since the use of BMPs are small and recent data show 
that cyanazine contamination of some surface water source drinking 
supplies continues to be a concern.
Comment: DuPont disagrees with the Agency's use of a 20 percent 
Relative Source Contribution (RSC) factor to calculate the HAL and 
suggests that the Agency revisit this issue before assessing risk based 
on the current number.
Agency Response: The RSC value is a factor that is used to establish 
regulatory standards for levels of a contaminant in drinking water. The 
RSC apportions the allowable doses of a contaminant that are derived 
from food, water and air. In the case of cyanazine, the Agency has used 
the default value of 20 percent due to lack of data to support any 
other value. In other words, the Agency is allowing only 20 percent of 
the total amount of cyanazine exposure to come from drinking water; the 
remaining 80 percent can be contributed through other exposure routes 
such as food and air. In 1994, DuPont requested that the Agency revise 
the RSC value and modify the cyanazine HAL accordingly. The Agency 
responded to DuPont's request, concluding that the 20 percent default 
value for the RSC was appropriate at this time due to uncertainties 
associated with the contribution of total triazines and their 
degradates to the total exposure. The Agency has received no additional 
information that warrants making this change and, therefore, continues 
to believe that the default value is appropriate. In the PD 1, the 
Agency's calculations to determine drinking water risk estimates do not 
use the RSC value or the HAL for cyanazine since actual intake survey 
data were used to estimate consumption of drinking water and monitoring 
data were used to estimate exposure to cyanazine. Therefore, changing 
the RSC value would have no effect on the Agency's drinking water risk 
estimates.
Comment: DuPont disagrees that inclusion of cyanazine metabolites may 
increase exposure to cyanazine by 10 percent. DuPont submitted data on 
metabolites in several reservoirs.
Agency Response: In the PD 1, the Agency's statement that degradates 
could increase exposure by 10 percent referred to total triazine 
degradates in general and did not refer specifically to cyanazine. The 
study on metabolites in reservoirs, to which DuPont refers, had very 
high detection limits for major cyanazine degradates; therefore, it is 
reasonable to conclude that cyanazine degradates were detected in a 
relatively low percentage of samples. However, in some of the samples 
where degradates were detected, they were at concentrations comparable 
to those of parent cyanazine.
Comment: DuPont agrees that there are numerous sites where a single 
measurement or even several measurements may exceed the HAL for 
cyanazine, yet the annual mean may not exceed the HAL. DuPont states 
that it is inappropriate to use chronic exposure standards in dealing 
with exposure from surface waters which are highly variable.
Agency Response: The Agency agrees that the concentration of individual 
surface water samples taken at a given point in time should not be 
compared to long-term regulatory standards and has only compared 
arithmetic and time-weighted annual mean concentrations to the HAL for 
cyanazine. The Agency has compared some maximum and individual 
cyanazine concentrations to short-term HALs and to 4 times the HAL. The 
rationale for comparing maximum or other individual concentrations to 4 
times the guidance value is that any single quarterly concentration 
that is greater than 4 times the guidance value will automatically make 
the annual average of four successive quarterly samples greater than 
the guidance value. If this guidance value was actually a regulatory 
standard, the system would be out of compliance with the Safe Drinking 
Water Act.
Comment: EPA reports that a high percentage of samples from the 
Chesapeake Bay have triazine detects. DuPont believes such detects 
should be quantified when assessing risk.
Agency Response: The statement in the PD 1 about a percentage of 
triazine detections in the Chesapeake Bay was intended to support the 
fact that the triazines are widely distributed in surface waters. The 
statement was not meant to be interpreted as any measure of risk but 
rather the far ranging distribution of the triazines in the 
environment. Also, the statement referred to atrazine only, not 
cyanazine, and stated that a small percentage of detections were 
greater than 3 g/L.
Comment: DuPont recommends that EPA reconsider appropriate action 
levels for regulating drinking water contaminants that can occur at 
varying levels over time. Using an identical exposure level over 70 
years of exposure represents excessive conservatism in risk management.
Agency Response: Actual exposure data on the same watershed over many 
years are not available so the Agency cannot conduct assessments as 
recommended by DuPont. Results using modeling, a possible future 
option, are currently not sufficiently reliable to use in absolute 
comparisons to MCLs or MCLGs. In addition, for regulatory purposes, the 
Safe Drinking Water Act requires the comparison of running annual 
average concentrations based upon four successive quarterly samples to 
be compared to the MCL. The Agency acknowledges that the use of water 
from the same source containing the same contaminant level is 
conservative since most of the U.S. population moves at some time 
during their life and does not live in the same area drinking from the 
same water source for a 70-year lifetime. However, it could be 
considered as 

[[Page 8194]]
either an over- estimation or under-estimation depending on the 
contaminant levels in the other sources of drinking water.
Comment: DuPont disagrees with EPA's statement that the concentration 
of cyanazine in a watershed is proportional to the watershed's size.
Agency Response: The Agency did not state that the concentration of 
cyanazine in a watershed is directly proportional to the watershed 
size. DuPont has misquoted the statement actually made in the PD 1. The 
Agency stated that ``peak concentrations of triazines are generally 
greater in surface waters draining small watersheds than in those 
draining large watersheds. . . .'' The statement was intended to be 
interpreted in the context of discussing watersheds which receive high 
cyanazine applications. As discussed earlier, smaller streams tend to 
have higher concentrations than do larger streams and rivers.
Comment: DuPont is not aware of any data showing that tile drainage 
and/or ground water inflow contributes substantially to cyanazine 
loading of surface waters.
Agency Response: Both Moyer and Cross (1990) and Squillace and Engberg 
(1988) believe that tile drainage and/or ground water inflow sometimes 
contribute significantly to triazine loadings of surface waters. 
Because cyanazine has a shorter half-life in surface soil than does 
atrazine, such contributions are probably substantially smaller for 
cyanazine than for atrazine.
Comment: DuPont commented that EPA indicates that the cumulative 
effects of various triazines are assumed to be additive. DuPont 
disagreed stating that information in a study report they submitted in 
response to the PD 1 entitled ``Assessment of the Reproductive and 
Developmental Toxicity of Pesticide/Fertilizer Mixtures Based on 
Confirmed Pesticide Contamination in California and Iowa Ground 
Water,'' indicates no additive effects and that safety margins in the 
HAL are more than adequate to protect human health and the environment.
Agency Response: Although it is unclear, the Agency assumes that DuPont 
is referring to additive toxic effects of pesticides as it relates to 
the Agency's combined risk assessment across several triazines and 
exposure routes in the PD 1. The study to which DuPont is referring 
assessed the reproductive and developmental toxicity, not 
carcinogenicity, of pesticide/fertilizer mixtures based on ground water 
contamination. The Agency continues to believe that additive effects of 
exposure to multiple chemicals may increase risks and will continue to 
evaluate and revise the combined risk assessment as appropriate though 
the continuing triazine Special Review. Safety margins built into HALs 
do not account for additive effects of multiple chemical exposures.
Comment: Griffin commented that the exposure values EPA used to 
characterize daily intake of drinking water are not consistent among 
the calculations to determine risk from exposure at the HAL, risk from 
surface water exposure and risk from ground water exposure or with 
accepted risk assessment methodology.
Agency Response: The Agency acknowledges that different body weight 
assumptions were used in calculating the risk assessment performed for 
exposure at the HAL (The Agency specified a 70 kg body weight and 2 L/
day water consumption value in the PD 1) than were used to calculate 
risks from ground and surface water consumption. Calculating risk at 
the HAL is a screening level assessment similar to using tolerance 
level residues to estimate risk for dietary consumption. The Agency 
acknowledges that there can be different default assumptions for water 
consumption; however, the 2L value used to determine the HAL is a 
traditionally accepted value. However, the Agency provided a refined 
assessment for the PD 1 that used actual ground and surface water 
monitoring data and self-reported body weights from the 1977 - 1978 
food consumption survey. Use of actual data to estimate risks, as was 
done in this case, provides a more realistic estimation than does using 
default assumptions such as exposure at the HAL or an assumed value for 
body weight.
Comment: Griffin stated that EPA has consistently used maximum or high-
end values in the drinking water evaluation. The basis for using time-
weighted averages is not clear. Actual exposure and risk is doubled 
because: (1) EPA has not considered surface water treatments that may 
reduce contamination, (2) it appears that EPA used a body weight of 50 
kg in its calculations, and (3) EPA applied an exposure value 
reflecting tap water only and not commercial beverages. EPA has used 
maximum values in its drinking water assessment even though cyanazine 
has actually been detected in few samples.
Agency Response: The Agency disagrees with Griffin's statement that 
maximum or high-end values have been used to estimate exposure in 
drinking water. The Agency has used time-weighted mean concentrations 
to provide a better estimate of the exposure to triazine residues over 
an extended period of time in order to reduce any over- or 
underestimation effects that may result from the variability of 
detection levels at specific sampling times. In estimating exposures in 
surface waters, time-weighted mean concentrations are generally better 
approximations of the actual time integrated mean concentration than 
are arithmetic means whose values tend to be greater due to the general 
increase in sampling frequency during periods when the highest triazine 
concentrations are expected.
    The Agency has not considered surface water treatment effects on 
the exposure to cyanazine because it cannot be assumed that all 
individuals are consuming drinking water that has actually been 
treated. It cannot be assumed that every household is connected to a 
public water system that provides adequate treatment to remove possible 
triazine contamination. Since most water systems employ only primary 
treatment methods (e.g., solids removal), cyanazine concentration in 
raw and in finished water should generally be comparable. It is true 
that the Agency did not include ``commercial water'' such as that added 
during the manufacturing and processing of beverages. The survey from 
which the Agency has taken the drinking water consumption value only 
included tap water that is consumed directly or that is used in the 
preparation of foods or beverages in the home.
Comment: DuPont submitted a number of studies in response to the PD 1 
that provides information about the effects of BMPs on cyanazine 
movement in the environment.
Agency Response: The Agency has not reviewed these studies to prepare 
this Notice. As discussed earlier, the Agency does not believe that the 
BMPs that have been put in place have totally addressed the Agency's 
ground and surface water concerns because of the more recent monitoring 
data that continue to show detections. These studies will be considered 
in the continuing Special Review of atrazine and simazine to evaluate 
the effects of BMPs on herbicide environmental contamination. Even 
though some of the BMPs may have a positive impact on ground and 
surface water contamination and potential ecological effects, the risk 
concerns associated with occupational exposure and dietary exposure 
from food consumption will remain unchanged.
Comment: The Environmental Working Group (EWG) submitted its report 
``Tap Water Blues'' to the Agency in response 

[[Page 8195]]
to the initiation of the triazine review. EWG also submitted a follow-
up report entitled ``Weed Killers by the Glass'' which indicates 
cyanazine detections in drinking water samples taken directly from the 
taps in people's homes or offices.
Agency Response: The Agency thinks that the data indicating cyanazine 
detections in drinking water are significant and support the Agency's 
risk concerns. As discussed earlier, some of the water systems that 
were sampled by EWG had time-weighted mean concentrations higher than 
the cyanazine HAL of 1.0 g/L. The Agency will fully evaluate 
the information with respect to atrazine and simazine as part of the 
continuing Special Review of the triazines.
Comment: EWG comments that EPA standards for triazines in food and 
drinking water are not consistent and allow levels in drinking water 
that are unsafe and would not be allowed in foods. EWG points out that 
there is no enforceable standard for cyanazine and recommends 
promulgation of a combined MCL for the triazines, including 
metabolites. NCAMP also commented that the Agency's regulation of 
contaminants in drinking water is less stringent than the regulation of 
residues in food and that metabolites should be included in all 
regulatory standards.
Agency Response: While the Agency does not have an MCL for combined 
triazines, including metabolites at this time, it is considering 
establishing such an enforceable standard. Because cyanazine is being 
phased out over the next several years, it is unlikely that the Agency 
will establish an MCL for cyanazine.
Comment: EWG recommends weekly monitoring of drinking water in 
susceptible regions for all triazines and metabolites during high 
runoff and vulnerable periods. EWG also recommended that exposure 
estimates must include recent data from Missouri and other states 
demonstrating that peak exposures and annual average concentrations for 
many rural communities far exceed health standards.
Agency Response: The Safe Drinking Water Act establishes the 
requirements for monitoring pollutants in drinking water. The Agency 
will consider the most recent monitoring data available to estimate 
triazine exposure in drinking water when the risk estimates are revised 
for the preliminary determination of the triazine Special Review.
Comment: EWG commented that the Agency must concentrate its risk 
assessment only on exposed populations. Unexposed populations deflate 
risks faced by people with contaminated water.
Agency Response: The Agency acknowledges the value of this comment and, 
providing that adequate information is available, will respond to this 
issue in the PD 2/3 for atrazine and simazine.

E. Occupational Exposure and Associated Risks

    For the PD 1, the Agency determined exposure estimates for 
cyanazine use on corn, the predominant use site, for different 
scenarios depending on whether the person exposed to cyanazine was 
mixing, loading or applying cyanazine or performing a combination of 
these tasks. Additionally, estimates were provided for growers and 
commercial applicators and whether open or closed equipment is used. 
Those estimates were based only on dermal exposure assuming a dermal 
absorption value of 2 percent and a use rate of 3 pounds active 
ingredient per acre (lb/ai/acre).
    Just prior to initiating the triazine Special Review, DuPont 
provided the Agency with its own occupational risk assessment that 
estimated exposure to cyanazine by using information in the Pesticide 
Handlers Exposure Database (PHED) for ground application (Ref. 7). 
After reviewing DuPont's assessment, the Agency revised its own risk 
assessment for ground application of cyanazine by using PHED 
information to estimate worker exposure (Ref. 8). Aerial application 
risks were not revised and remain as reported in the PD 1. The Agency 
used a more recent version of PHED (version 1.1) than did DuPont 
(version 1.01) that contains more data and therefore provides a greater 
degree of confidence in the exposure estimates. Table 3 below provides 
the Agency's revised occupational risk estimates as well as DuPont's 
estimates for groundboom application of cyanazine.

                                  Table 3--Exposure and Risk Estimates for Groundboom Applications of Cyanazine to Corn                                 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Daily Exposure mg/  Annual Exposure                       Estimated Upper     Estimated Risk 
                                                                 kg/day           mg/kg/year       LADE mg/kg/day    Bound Risk (EPA)       (Dupont)    
--------------------------------------------------------------------------------------------------------------------------------------------------------
Grower                                                                                                                                                  
Mixer/Loader Open                                                     0.0099             0.0109         1.5 x 10-5         1.5 x 10-5        1.71 x 10-6
Applicator Open                                                       0.0044             0.0048         6.5 x 10-6         6.5 x 10-6         5.2 x 10-7
M/L/A Open                                                            0.0143             0.0157         2.2 x 10-5         2.2 x 10-5        2.23 x 10-6
Mixer/Loader Closed                                                   0.0020             0.0022         3.0 x 10-6         3.0 x 10-6                N/A
Applicator Closed                                                     0.0016             0.0018         2.4 x 10-6         2.4 x 10-6                N/A
M/L/A Closed                                                          0.0036             0.0040         5.4 x 10-6         5.4 x 10-6                N/A
                                                                                                                                                        
Commercial                                                                                                                                              
Mixer/Loader Open                                                     0.0729             0.0874         1.2 x 10-4         1.2 x 10-4        5.28 x 10-5
Applicator Open                                                       0.0321             0.0385         5.3 x 10-5         5.3 x 10-5        4.64 x 10-6
M/L/A Open                                                            0.1050             0.1259         1.7 x 10-4         1.7 x 10-4        5.75 x 10-5
Mixer/Loader Closed                                                   0.0147             0.0177         2.4 x 10-5         2.4 x 10-5                N/A
Applicator Closed                                                     0.0117             0.0139         1.9 x 10-5         1.9 x 10-5                N/A
M/L/A Closed                                                          0.0264             0.0316         4.3 x 10-5         4.3 x 10-5                N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------

Daily Exposure = lb ai/day X Unit exposure X % Dermal absorption/70
Annual Exposure = lb ai/year X Unit exposure X % Dermal absorption/
70
LADE = Annual exposure } 365 X 35/70
Risk = LADE X Q*
Dermal absorption = 2% (DuPont's estimates are based on 1% dermal 
absorption)
Q* = 1

[[Page 8196]]


F. Comments Regarding Cyanazine Occupational Exposure Risk Estimates 
and Agency's Response

Comment: Griffin asserts that: (1) EPA has used an application rate of 
3 lb/ai/a, but states that 1.5 lb/ai/acre is commonly used for 
cyanazine, and that using the higher rate is a violation of EPA's legal 
obligation to base regulatory activities on actual data, (2) EPA used a 
dermal absorption value of 2 percent to calculate risks, while studies 
indicate the actual dermal absorption value to be .84 percent, and (3) 
EPA's risk assessment is overestimated and meaningless because 
application rates were doubled and the dermal absorption value was 
exaggerated.
Agency Response: The Agency has estimated occupational exposure to 
cyanazine based on an application rate of 3 pounds per acre when 
applying cyanazine alone. The Agency noted in its risk assessment that 
a rate of 1.5 pounds per acre is often used; however, this rate is 
typically used when cyanazine is applied in combination with another 
herbicide, often atrazine. While some cyanazine usage occurs at rates 
greater than 3 lb/ai/acre (up to greater than 5.0 lb/ai/acre) the 
majority of usage occurs at rates of 3 lb/ai/acre or less. The dermal 
absorption rate used in the Agency's risk calculation is based on the 
actual amount absorbed plus the amount remaining bound to the skin 
after washing as shown in a dermal absorption study. Therefore, the 2 
percent value used in the Agency's risk assessment represents the total 
amount of cyanazine that could potentially be absorbed through the 
skin. Assuming that the amount remaining bound to the skin after 
washing will be absorbed over time is consistent with the Office of 
Pesticide Programs' risk assessment practices.
Comment: DuPont commented that occupational exposure risks were in the 
acceptable range and referenced their risk assessment submitted to the 
Agency.
Agency Response: After reviewing DuPont's assessment, the Agency 
revised its occupational risk assessment and then compared the two. In 
using updated PHED information, the Agency's revised risk estimates 
were lower than those estimates originally reported in the PD 1; 
however, the risk estimates are not as low as those estimated in 
DuPont's assessment. The assumptions that the Agency used in its risk 
estimates vary from the assumptions used by DuPont. The Agency's unit 
exposure estimates are based on a newer version of PHED and the Agency 
has also used a different dermal absorption value than DuPont, as 
discussed above. The Agency used information from PHED derived from 
atrazine studies in which application parameters comparable to those 
for cyanazine were used. DuPont's assessment for applicators is 
unacceptable due to the lack of sufficient replicates used. Most of the 
exposure estimates for applicators were based on data representing less 
than the required minimum of 15 replicates per body part. Further, for 
some of the exposure scenarios used by DuPont, the risks were higher 
than negligible and of concern. The Agency has used updated use and 
usage information to estimate the number of acres treated for exposure 
estimations. Therefore, the Agency believes its revised estimates are 
more accurate than those presented in the PD 1 and those calculated by 
DuPont.

G. Combined Cancer Risks Across Multiple Exposure Pathways and 
Chemicals

    In the notice initiating the Special Review of the triazine 
herbicides, the Agency provided examples of assessments of total risk 
that was possible to individuals who may be exposed to more than one of 
the triazines and from more than one exposure pathway. This was the 
first time that the Agency looked at the additive risks associated with 
a group of similar pesticide chemicals. In the combined risk 
assessment, the Agency provided estimates of the total risk from 
exposure to atrazine, simazine and cyanazine from dietary, drinking 
water, occupational and residential exposure. In the PD 1, the Agency 
acknowledged that various total risk estimates were possible depending 
on the combination of chemicals to which one is exposed and the 
combination of exposure routes. With the ultimate phaseout of the use 
of cyanazine, this chemical will eventually cease to contribute to the 
total combined triazine risk. However, during the phaseout, while 
cyanazine continues to be used, the Agency will continue to evaluate 
its contribution to the total risks of the triazine herbicides in 
Special Review. Table 4 below shows the Agency's upper bound estimates 
of total cancer risks across several exposure pathways and triazines.

             Table 4.--Upper Bound Total Cancer Risks Across Several Exposure Pathways and Triazines            
----------------------------------------------------------------------------------------------------------------
        Exposure Pathway               Atrazine            Simazine           Cyanazine1             Total      
----------------------------------------------------------------------------------------------------------------
Dietary                           4.4 x 10-5          1.1 x 10-5          2.7 x 10-5          8.2 x 10-5        
Drinking Water2                   4.2 x 10-6          6.2 x 10-7          9.7 x 10-6          1.5 x 10-5        
Occupational3,4                   1.1 x 10-3          N/A                 N/A                 1.1 x 10-3        
Residential5                      1.1 x 10-4          N/A                 N/A                 1.1 x 10-4        
Total                             1.3 x 10-3          1.2 x 10-5          3.7 x 10-5          1.3 x 10-3        
----------------------------------------------------------------------------------------------------------------

    1Risk contribution from use on wheat not included.
    2Derived from surface water.
    3Private grower application to corn using ground boom 
equipment - mixer/loader/applicator.
    4Application of a combination of atrazine and cyanazine.
    5Lawn treatment by homeowner using hand cyclone spreader.

H. Comments Regarding Combined Risk Estimates and Agency's Response

Comment: Griffin commented that EPA has failed to recognize that a 
critical factor to be addressed when combining risks is the compounding 
of maximum values. For example, if 90th percentile values are used to 
assess risk for each pathway to be combined, the total risk actually 
represents an estimate closer to a 95-99th percentile range, an 
overexaggeration that reduces the value of the risk estimate for 
decision making.
Agency Response: The Agency acknowledges that a simple additive 
approach was used in combining the risks for atrazine, simazine, and 
cyanazine. This approach was deemed scientifically sound as the 
estimates were based on the induction of the same tumor type in the 
same animal strain, quite possibly via the same or similar mode or 
mechanism of action. The combined risk estimate contains all of the 
uncertainties of the numbers used in the individual calculations. If 
all of the triazine risk numbers were roughly of 

[[Page 8197]]
the same magnitude, then addition of many upper bound numbers could 
eventually lead to an over-estimate of risk. However, adding upper 
bounds in this case should not be considered to over-estimate the risk 
since one chemical or one pathway ``drives'' the risk. In the case of 
the triazines, the occupational risk from atrazine of 1.1 x 10-3 
is driving the overall risk of 1.3 x 10-3.
Comment: EWG and NCAMP support the Agency's combined risk assessment 
for the triazines. EWG requests that the Agency calculate the effect of 
exposure to infants and children on their lifetime cancer risks, the 
average exposure levels for infants and young children, the degree to 
which it is disproportionately occurring in early life and the 
significance of this exposure. NCAMP further urges the Agency to extend 
that risk assessment concept to include all pesticides with similar 
toxic endpoints.
Agency Response: The Agency agrees that it is important to consider the 
differences between infants, children, and adults when estimating risks 
and is working to develop scientifically-sound methodologies to account 
for such differences in sensitivity and/or exposure and their impact on 
the lifetime cancer risk estimates. Many factors such as the length of 
exposure and variations in exposure levels need to be considered in the 
risk assessment process. The triazines Special Review is the first case 
study for estimating total risks from chemicals which are similar. The 
Agency will likely apply the principles that are used in the combined 
risk assessment in the triazine case study to estimate combined risks 
from other pesticides that have concurrent exposure and/or common 
mechanisms of toxicity in future risk assessments.

IV. Summary of Exposure and Related Ecological Risks

    At the time the Agency initiated the Special Review of atrazine, 
simazine, and cyanazine, it did not include ecological risk as a formal 
trigger to initiate the review. The Agency did, however, express 
concerns about the potential risks to aquatic organisms, terrestrial 
plants and their ecosystems. The Agency based its concern on a number 
of studies that indicate acute effects on various aquatic organisms and 
terrestrial plants. These studies were discussed in detail in the PD 1 
and the Agency requested any additional information about ecological 
effects at the time the Notice was published. The Agency did not 
receive any new information or new studies that either supported or 
rebutted its concern about potential ecological risks from the use of 
the triazines; therefore the Agency has not changed its position 
regarding the ecological effects. Even though this Notice is proposing 
the termination of the cyanazine Special Review, the Agency will 
continue to look at adverse effects on ecological parameters in the 
continuing Special Review of atrazine and simazine.

Comments Regarding Ecological Risks and Agency's Response

Comment: NCAMP supported the Agency's concerns about potential 
ecological risks associated with the triazines and cited a number of 
published studies about the toxic effects on aquatic and terrestrial 
organisms.
Agency Response: NCAMP did not provide any information other than 
citing several studies about the potential ecological risks of the 
triazines. The Agency conducted a comprehensive literature search and 
considered all published information in its assessment of triazine 
ecological risks at the time the triazine PD 1 was issued. The studies 
that supported the Agency's ecological concerns are discussed in detail 
in the PD 1. In the PD 1, the Agency stated that exclusion of 
ecological risks as a Special Review trigger at that time would not 
preclude the Agency from including those risks in the review at a later 
time, should additional information warrant it. The Agency will 
continue to evaluate ecological concerns as the Special Review of 
atrazine and simazine proceeds. If new information becomes available 
that changes the Agency's position regarding the ecological risks of 
atrazine and simazine, the Agency may include them in the Special 
Review.

V. Summary of Qualitative Benefits and Impacts of Phaseout and 
Voluntary Cancellation

    Cyanazine is a broad spectrum herbicide which is registered for the 
control of many annual grasses and broadleaf weeds in corn, cotton, and 
sorghum. About 23 - 36 million pounds active ingredient of cyanazine 
are applied each year in the U.S. Corn accounts for 95 percent of 
cyanazine usage with between 18 and 21 percent of the field corn 
acreage treated each year. Cotton accounts for about 3 percent of all 
usage with between 12 and 20 percent of the cotton acreage treated 
annually. Sorghum and sweetcorn account for less than 1 percent of all 
cyanazine usage with between 1 and 3 percent of the sorghum acreage and 
about 20 percent of sweet corn acreage treated annually.
    Cyanazine provides the grower with flexibility of application 
(preplant, preemergence, postemergence) and residual activity in 
addition to burndown in no-till crop management. A second advantage, 
compared to the widely used atrazine-based products, is that cyanazine 
is less persistent following application, which results in shorter 
residual activity. Thus, a significant advantage of cyanazine alone or 
in mixtures with atrazine, compared to atrazine alone or atrazine in 
combination with other herbicides, is the ability to plant any 
triazine-sensitive rotational crop in the fall or the spring following 
the application without the concern of carryover. This flexibility is 
extremely important in regions where growing seasons are shorter, which 
may result in herbicide applications being made later in the spring. A 
third advantage is that cyanazine offers the grower a wide weed control 
spectrum, especially against several problem grass species. Therefore, 
in some cases a second grass herbicide may be unnecessary, or can be 
used at a reduced application rate.
    The Agency has evaluated how the phaseout of cyanazine will impact 
users as compared to an immediate cancellation. Data and information 
from publications of the USDA National Agricultural Statistical Service 
(NASS), USDA/University State Extension Pesticide Use Recommendation 
Reports, other proprietary marketing research sources, and comments 
received in response to the triazine PD 1 were used as the basis for 
this analysis. Although USDA National Agricultural Pesticide Impact 
Assessment Program (NAPIAP) reports on field corn (1995), cotton 
(1993), and sorghum (1994) exist, they have limited usefulness to EPA 
in terms of quantitative estimates of impacts.
    The NAPIAP reports generally contain estimates of yield losses and 
direct costs resulting from the use of some alternative chemicals. The 
NAPIAP report on corn also includes estimates of crop damage. The yield 
loss estimates were based on a survey of regional weed scientists. For 
the corn assessment, scientists from 15 states were interviewed as a 
group to encourage dialogue. Survey responses were then used as a basis 
for quantitative estimates of the economic impact of a cancellation of 
cyanazine and substitution of alternative control methods. The report 
does not specify the basis for the opinions of the weed scientists. 
Thus, it is not clear to what extent the opinions of the weed 
scientists are based on comparative product performance tests or other 
comparable scientific data. The Agency has concluded that a reliable 
projection of the comparative performance of pesticide products must 

[[Page 8198]]
be based on scientifically derived data. Projections based solely on 
opinions, even the opinions of experts, do not provide a sufficiently 
reliable basis for the quantitative estimation of economic impacts. 
Accordingly, the Agency has not relied on the NAPIAP reports to 
estimate potential economic impacts of the cancellation or phaseout of 
cyanazine registrations.
    The NAPIAP reports are limited in several other respects. The 
commodity assessments do not focus on cyanazine, nor do they address 
specific aspects that could affect the impacts associated with its 
anticipated phaseout. Additional factors that were not considered in 
the NAPIAP reports include tillage practices, potential for crop 
injury, farm size, and regional preferences that could also influence 
the overall economic impacts to users. Perhaps most significantly, the 
corn and cotton assessments were completed before several newly 
registered herbicides entered the market, so they were not considered.
    The Agency has not adopted the NAPIAP reports' quantitative 
estimates of the economic impacts of a cancellation or phaseout, but 
has used the reports for other purposes in the Agency's analysis. For 
example, the NAPIAP reports do provide useful information about the 
manner and extent of cyanazine use. The NAPIAP quantitative estimates 
have been used only for the limited purpose of illustrating the 
relative economic differences between the two regulatory options: a 
complete cancellation or a phase-down of use followed by a complete 
cancellation. In such an analysis, the accuracy and reliability of the 
NAPIAP quantitative estimates are not crucial because the Agency is 
using them for the limited purpose of illustrating the relative 
relationship between the two regulatory options.
    Because the terms and conditions of the cyanazine phaseout call for 
incremental annual reductions in cyanazine usage beginning in 1997, 
reaching a maximum of 1 lb/ai/a in 1999, and requirements for closed 
cab application equipment beginning in 1998 and remaining throughout 
the phaseout period, the full impacts of the cyanazine phaseout will 
not be realized until after 2002, when all use of the chemical is 
prohibited. However, the Agency does believe that some impacts will 
occur during the phaseout period as a result of a decrease in the 
maximum rates allowed per acre and the closed cab requirements.
    Most cyanazine users are not expected to be adversely affected by 
the phaseout until the maximum use rate drops below the rate at which 
they are currently applying the chemical. For example, the majority of 
cyanazine usage on corn is applied at rates between 1 and 3 lb/ai/acre. 
Therefore, the use on corn will not be significantly affected until 
1999 when the maximum rate is reduced to 1 lb/ai/acre. Similarly, for 
cotton, the majority of usage occurs at rates of less than 1 lb/ai/a; 
therefore, most uses in cotton will remain unaffected, assuming 
adequate supplies, through 2002, at which time cyanazine will no longer 
be available for use. Table 5 below presents the frequency distribution 
of cyanazine acre treatments by application rate for each of the use 
sites.

          Table 5.--Distribution of Cyanazine Usage (Acre Treatments) by Application Rate (1993 - 1994)         
----------------------------------------------------------------------------------------------------------------
    Application Rate (lb/ai/acre)             Field Corn                 Cotton                 Sweet Corn      
----------------------------------------------------------------------------------------------------------------
0 to 1                                 18%                      91%                      16%                    
>1 to 3                                72%                      8%                       81%                    
>3 to 5                                9.8                      1%                       3%                     
>5 to 6.5                              0.2%                     --                       --                     
Total                                  100%                     100%                     100%                   
----------------------------------------------------------------------------------------------------------------

    Source: U.S. EPA; Based on proprietary and publicly available 
data.
    The Agency acknowledges that some benefits are associated with the 
use of cyanazine throughout the phaseout period; however, quantitative 
estimates of the impact of the phaseout have not been determined. As 
discussed earlier, the Agency has used the quantitative estimates of an 
immediate cancellation as reported by NAPIAP for the limited purpose of 
illustrating the relative differences between a phaseout of cyanazine 
followed by a complete cancellation and an immediate cancellation. The 
Agency has not relied on the NAPIAP reports to estimate the potential 
economic impact of the phaseout and cancellation of cyanazine other 
than to merely illustrate that a phaseout incurs less of an impact to 
growers than would an immediate cancellation. The NAPIAP reports 
estimate that the aggregrate economic impacts of an immediate ban of 
cyanazine would be $25 million for corn and $14 million for cotton. In 
Table 6, the NAPIAP estimates have been used to illustrate the 
ameliorating effect that the phaseout of cyanazine may have on 
individual uses (Ref. 12).

                               Table 6--Allocation of the Impacts of the Phaseout and Voluntary Cancellation of Cyanazine                               
--------------------------------------------------------------------------------------------------------------------------------------------------------
                Year                  App Rate (lb/ai/acre)     Field Corn ($mil)        Cotton ($mil)        Sweet Corn ($mil)     Total Impacts ($mil)
--------------------------------------------------------------------------------------------------------------------------------------------------------
1996                                 6.5                     $0.00                   $0.00                  $0.00                  $0.00                
1997                                 5                       $0.05                   $0.00                  $0.00                  $0.05                
1998                                 3                       $6.8                    $8.6                   $0.1                   $15.5                
1999                                 1                       $21.4                   $9.0                   $0.7                   $31.1                
2000                                 1                       $21.4                   $9.0                   $0.7                   $31.1                
2001                                 1                       $21.4                   $9.0                   $0.7                   $31.1                
2002                                 1                       $21.4                   $9.0                   $0.7                   $31.1                
2003                                 0                       $25                     $14                    $0.8                   $39.8                
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 8199]]


    While the Agency has used the NAPIAP quantitative estimates of 
impacts in Table 6 above, the Agency neither accepts nor rejects them. 
The quantitative estimates are used only to illustrate the relative 
difference between immediate cancellation and a phaseout.
    1. Field corn. Between 18 and 21 percent of the 73 million acres 
planted to field corn receives one or more applications of cyanazine 
per growing season at an average rate of 1.9 lb/ai/acre. Approximately 
22 - 33 million pounds of cyanazine are applied annually. Treatments 
are predominantly preemergence and preplant incorporated; however, 
cyanazine combined with atrazine is commonly used in no-till corn as an 
early post-emergence or burndown agent. Cyanazine is applied alone or 
in combination with another herbicide approximately 35 and 65 percent 
of the time, respectively. About 90 percent of cyanazine products are 
applied broadcast using ground equipment and most of the remaining 10 
percent applied as a band treatment. Cyanazine used alone is applied at 
an average rate of 2.25 lb/ai/acre. When used in combination with 
another herbicide, cyanazine is applied at an average rate of 1.67 lb/
ai/acre.
    The majority of users who apply cyanazine to field corn will not be 
affected until 1999 when the maximum use rate is lowered to 1 lb/ai/a. 
However, about 10 percent of cyanazine usage does occur at rates of 3 
lb/ai/acre or higher on heavier clay soils that generally contain 
greater than 3 percent organic matter or on soils with greater than 30 
percent surface residue. In 1999, when the maximum rate is reduced to 1 
lb/ai/a, approximately 82 percent of cyanazine usage will be affected. 
Compared to an immediate cancellation, the phaseout reduces annual 
impacts because cyanazine will continue to be available to some growers 
through 2002. Table 6 above illustrates the ameliorating effect that 
the phaseout of cyanazine followed by a voluntary cancellation has on 
corn growers relative to an immediate ban. Efficacious alternatives to 
cyanazine include atrazine, nicosulfuron, metolachlor, alachlor, 
dicamba, acetochlor, halosulfuron and prosulfuron.
    2. Cotton. Cotton is the second largest crop on which cyanazine is 
used and it accounts for 3 percent of the total cyanazine used in the 
United States or about 1 - 2 million pounds of active ingredient. About 
62 percent of cyanazine usage in cotton are postemergence directed 
applications, 25 percent are preemergence applications and 11 percent 
are layby applications. About 12 - 20 percent of the U.S. cotton 
acreage received a cyanazine application at an average rate of 0.8 lb/
ai/a. Preplant applications were typically made at the rate of 1.5 - 
2.0 lb/ai/acre while postemergence applications were made at the rate 
of 0.5 - 1 lb/ai/a. Alternatives that are available for use on cotton 
include diuron, fluometuron, oxyfluorfen, prometryn, and the recently 
registered herbicide pyrithiobac-sodium. Since the majority of 
cyanazine usage in cotton occurs at rates less than 1 lb/ai/a, the 
phaseout should not adversely impact cotton growers until cyanazine use 
is prohibited after 2002. Table 6 above illustrates the ameliorating 
effect that the phaseout of cyanazine followed by a voluntary 
cancellation has on cotton growers relative to an immediate ban.
    3. Sweet Corn. Approximately 200,000 to 300,000 pounds active 
ingredient of cyanazine is applied to sweet corn per year at an average 
rate of 1.5 lb/ai/acre. About 6 percent of the 164,000 acres of fresh 
market sweet corn and about 24 percent of the 503,000 acres of 
processed sweet corn receive cyanazine applications, with Wisconsin, 
Illinois, New York, Michigan, New Jersey, and Minnesota having 
significant cyanazine use on this commodity. The heavy usage in 
Wisconsin is probably due to the restrictions placed on atrazine in 
that state. There are fewer alternative herbicides registered for use 
on sweet corn than for field corn, with atrazine being the primary 
preemergence alternative. Dicamba and 2,4-D are postemergence 
alternatives for broadleaf weed control and alachlor and metolachlor 
are alternatives for grass control.
    As stated earlier, no published information was available that 
estimated the impacts of the unavailability of cyanazine for sweet corn 
production. The Agency calculated estimates for sweet corn based on 
information that was available for field corn. The economic impact on 
field corn is adjusted to account for differences between the total 
acres planted and the per acre value of sweet corn and field corn. The 
following formula is used to estimate this impact:
    Sweet Corn Impact = Field Corn Impact ($25 million) x total acres 
sweet corn (800,000)/total acres field corn (70,000,000) x per acre 
value sweet corn ($850)/per acre value field corn ($303).
    The per acre value of sweet corn is a weighted average of sweet 
corn grown for the fresh market (224,900 acres, $373.7 million) and the 
processed market (516,200 acres, $256.1 million). The per acre value of 
field corn was calculated on the basis of 72.9 million acres with a 
total crop value of $22.16 billion. Using the above formula, the annual 
economic impact of banning cyanazine use on sweet corn is estimated to 
be $0.8 million. Annual impacts that result from the phaseout of 
cyanazine will not significantly impact sweet corn growers until 1999 
when the maximum allowable application rate is reduced to 1 lb/ai/a.
    Wisconsin sweet corn growers may be severely impacted by the 
phaseout of cyanazine since it is believed that a large percentage of 
cyanazine usage in that state is a result of the state restrictions 
that have been placed on atrazine. In some counties, rate restrictions 
have reduced the performance of atrazine as a preemergence treatment. 
Therefore, sweet corn growers may have to resort to using postemergence 
herbicides to control broadleaf weeds unless new preemergence 
herbicides are registered. The Agency anticipates that the impact to 
sweet corn growers will be similar to that anticipated for field corn 
growers. Table 6 above illustrates the ameliorating effect that the 
phaseout of cyanazine followed by a voluntary cancellation has on sweet 
corn growers relative to an immediate ban.

Comments Regarding Benefits of Cyanazine and the Agency's Response

    A number of commenters, including academia and weed extension 
scientists, grower groups, and chemical producers, submitted comments 
about the general benefits of cyanazine use in agricultural practices. 
These general arguments support cyanazine's continued use because of 
its shorter residual life and therefore less crop rotation 
restrictions, better control of certain grass weeds other than 
triazines, effectiveness against germinating and emerged weeds with 
good burndown action in no-till practices, role in weed resistance 
management, no drift damage to sensitive crops nearby, and its 
generally greater flexibility in weed control programs. The Agency 
acknowledges that there are certain benefits associated with the use of 
cyanazine and, as required, has considered all of cyanazine's 
advantages in its assessments.
Comment: NCAMP and EWG criticized the methodology of the Agency's 
analyses of pesticide benefits. NCAMP commented that a comprehensive 
benefits assessment will demonstrate the appropriateness of cancelling 
all registrations of the triazines. NCAMP further stated that the 
Agency's method of assessing benefits is inappropriate because the 
assessment looks only at 

[[Page 8200]]
alternative chemical means of controlling weed pests. The EWG commented 
that the Agency must consider the total social costs of using 
pesticides in its benefits assessment and that it is not proper to 
allow a chemical risk to support the production of commodities that are 
subsidized and where supply exceeds demand.
Agency Response: Because these comments were not specific to cyanazine, 
the Agency intends to respond to them later in the Special Review when 
comments on all triazines are addressed, unless it receives additional 
comments demonstrating that these criticisms apply specifically to 
cyanazine.
Comment: Griffin provided an assessment of the general benefits of 
cyanazine that addressed the following aspects of cyanazine: (1) 
Importance in controlling a wide spectrum of weeds, (2) providing 
greater crop rotation flexibility, (3) usefulness in no-till practices, 
(4) weed resistance management, and (5) lower cost than alternative 
chemicals.
Agency Response: The Agency agrees with Griffin that cyanazine offers 
those benefits as Griffin pointed out; however, the Agency also 
believes that alternative herbicides are available that provide 
comparable weed control at similar costs. Earlier in this Notice, the 
Agency acknowledged many of the same advantages of using cyanazine as 
Griffin noted.

VI. Risk/Benefit Analysis and the Agency's Proposed Decision 
Regarding Special Review

A. Risks

    The terms and conditions of the phaseout and cancellation are 
expected to reduce risk from use of cyanazine as estimated in the 
cyanazine PD 1 to zero over the course of the phaseout and depletion of 
existing stocks. While both users and the public will be subject to 
some continued risk during this time, the risk to users will decline 
during the phaseout and depletion of existing stocks due to the 
imposition of use restrictions and the risk to the public will decline 
due to the reduction in use rates.

B. Benefits

    In Unit V. of this Notice, a discussion of the impacts of phasing 
out cyanazine compared to an immediate cancellation is presented. The 
cyanazine phaseout allows for a gradual reduction in use of the 
chemical over a period of 7 years.
    There are a number of elements inherent in the phaseout of 
cyanazine that will, in effect, lessen the economic impact to growers 
who have used cyanazine in their weed management practices in the past. 
First, the phaseout should allow growers sufficient time to find 
suitable alternatives to replace cyanazine, thereby causing little 
disruption to agricultural production. For example, the majority of 
cyanazine used is applied to field corn. With the phaseout, there will 
be little impact to corn growers until 1999 when the maximum allowable 
use rate drops to 1 lb/ai/a. With all uses, the full impact of the 
phaseout will not be realized until after 2002 when cyanazine use will 
be prohibited.

C. Risks of Alternatives

    The Agency has identified the major chemical alternatives to 
cyanazine in this Notice. Atrazine, one alternative to cyanazine, was 
placed into Special Review concurrently with cyanazine based on the 
potential risk of carcinogenicity to humans. No significant risk 
concerns have been identified with the other alternatives except for 
2,4-D, which is currently being considered for possible Special Review 
pending results of further studies on its carcinogenic potential.

D. Risk/Benefit Analysis

    In light of the terms and conditions of the DuPont and Griffin 
cyanazine registrations, the Agency has considered the risks and 
benefits of cyanazine for the remaining 7 years that the pesticide will 
be allowed for use. During the phaseout, people will be exposed to 
cyanazine for a limited time period during which application rates will 
be reduced and closed cab application equipment will be required. As 
discussed earlier, the Agency believes that the potential risks that 
may result, while considering the factors of time and exposure imposed 
by the cyanazine phaseout, will be less than those risks articulated in 
the PD 1. Further, the Agency has evaluated the impacts of the 
cyanazine phaseout and has concluded that there are benefits associated 
with the phaseout of cyanazine.
    The phaseout also confers benefits by making it unnecessary to 
recall and dispose of unused product and by allowing users to reduce 
costs through various mechanisms such as allowing them time to 
gradually modify weed management strategies to replace cyanazine. The 
Agency also considered the costs, time, and uncertainties associated 
with involuntary imposition of regulatory measures. In the absence of 
the voluntary cancellation and phaseout, the Agency may have used its 
authority under FIFRA section 6 to cancel cyanazine registrations. The 
Agency believes that this action would have been contested and would 
have required enormous resources and several years of litigation before 
a final order could have been implemented. The resources saved by 
voluntary cancellation and phaseout may now be applied to risk 
reduction of other products. Also, a contested cancellation would not 
have brought about the phased-in measures to reduce risk as currently 
provided for by the terms and conditions of the voluntary cancellation 
and phaseout. Finally, the outcome of litigation is uncertain in both 
result and when those results may be achieved; the voluntary 
cancellation and phaseout has set a firm schedule for the 
implementation of risk reduction measures and has established a date 
certain for the final cancellation of cyanazine registrations.
    For all of the foregoing reasons, the Agency has determined that 
implementation of the voluntary cancellation and phaseout of cyanazine 
will eliminate the potential risks posed by cyanazine identified in the 
triazine PD 1.

E. Proposed Decision Regarding Special Review

    In view of its determination discussed above, that the terms and 
conditions of the cyanazine voluntary cancellation and phaseout will 
eliminate any unreasonable adverse effects posed by the registration of 
cyanazine, the Special Review need not be continued.

VII. Request for Voluntary Cancellation

    As part of the terms and conditions of all registered cyanazine 
products, including those of both DuPont and Griffin, voluntary 
cancellations of all cyanazine registrations will become effective 
December 31, 1999. Shortly thereafter, the Agency will issue a 
cancellation order for all cyanazine products. Also, as part of the 
terms and conditions, EPA is required to provide advance public 
notification of the voluntary cancellation of cyanazine products as 
part of the proposal to terminate the Special Review of cyanazine. This 
section, Unit VII., will serve as the Agency's notification of the 
requests for voluntary cancellation.
    The cyanazine products that, according to the amended terms and 
conditions of cyanazine registration, will be voluntarily canceled, 
effective December 31, 1999, are listed below by EPA registration 
number and product name.

[[Page 8201]]


                                                                        
                                                                        
             Registration No.                       Product Name        
                                                                        
352-475                                    DuPont Cyanazine Technical   
352-470                                    DuPont Bladex (R)4L Herbicide
352-495                                    DuPont Bladex (R)90 DF       
                                            Herbicide                   
352-500                                    DuPont Extrazine (R)II 4L    
                                            Herbicide                   
352-577                                    DuPont Extrazine (R)II DF    
                                            Herbicide                   
1812-364                                   Griffin Cyanazine Technical  
1812-365                                   Griffin Cynex DF             
1812-366                                   Griffin Cynex 4L Herbicide   
                                            Liquid                      
1812-367                                   Griffin Cynex Extra 4L       
1812-368                                   Griffin Cynex Extra DF       
                                                                        

    Comments on the requests for voluntary cancellation of these 
registrations may be submitted to the contact person listed under the 
FOR FURTHER INFORMATION CONTACT unit of this document during the 30-day 
comment period provided in this Notice.
    Also included in the terms and conditions of cyanazine 
registrations is a provision for allowing the continued distribution 
and use of cyanazine end use products beyond the effective voluntary 
cancellation date. The terms and conditions specifically state that all 
cyanazine formulated end use products released for shipment by a 
registrant on or before December 31, 1999, may continue to be 
distributed and sold in the channels of trade in accordance with labels 
through September 30, 2002. The terms and conditions further state that 
use of such existing products in accordance with their labels may 
continue through December 31, 2002. All labels of cyanazine formulated 
end use products released for shipment by a registrant after July 25, 
1996, will state that the product may not be sold or distributed after 
September 30, 2002, and that the products may not be used after 
December 31, 2002. The existing stocks provision will allow any 
remaining product in the channels of trade to be used, thereby 
precluding the need for recall and disposal of unused product.

VIII. Public Comment Opportunity

    During the 30-day comment period, specific comments are requested 
on the Agency's preliminary determination to terminate the Special 
Review of cyanazine and on the requests for voluntary cancellation of 
cyanazine products. The Agency will review and consider any comments 
received during the official comment period before issuing a final 
determination on conclusion of the Special Review of cyanazine. All 
written comments submitted pursuant to this Notice, except ``CBI,'' 
will be available for public inspection in Rm. 1132, CM #2, 1921 
Jefferson Davis Highway, Arlington, VA Telephone: 703-308-5805.
    Comments claimed as CBI must be clearly marked as ``confidential,'' 
``trade secret,'' or other appropriate designation on the face of the 
comments. Comments marked as such will be treated in accordance with 
the procedures in 40 CFR 2.204(e)(4). Comments not claimed as 
confidential at the time of submission, or not clearly labeled as 
containing CBI, will be placed in the public docket. The Agency will 
consider the failure to clearly identify the claimed confidential 
status on the face of the comment as a waiver of such claim, and will 
make such information available to the public without further notice to 
the submitter.
    All comments and information should be submitted in triplicate to 
the address given in this Notice under ADDRESSES to facilitate the work 
of EPA and others interested in inspecting them. The comments and 
information should bear the docket control number, ``OPP-30000/60A.''

IX. Public Docket

     A record has been established for the action under docket number 
``OPP-30000/60A'' (including comments and data submitted electronically 
as described below). A public version of this record, including 
printed, paper versions of electronic comments, which does not include 
any information claimed as CBI, is available for inspection from 8 a.m. 
to 4:30 p.m., Monday through Friday, excluding legal holidays. The 
public record is located in Rm. 1132 of the Public Response and Program 
Resources Branch, Field Operations Division (7506C), Office of 
Pesticide Programs, Environmental Protection Agency, Crystal Mall #2, 
1921 Jefferson Davis Highway, Arlington, VA.
    Electronic comments can be sent directly to EPA at:

    [email protected]

    Electronic comments must be submitted as an ASCII file avoiding the 
use of special characters and any form of encryption.
    The official record for the document, as well as the public 
version, as described above will be kept in paper form. Accordingly, 
EPA will transfer all comments received electronically into printed, 
paper form as they are received and will place the paper copies in the 
official record which will also include all comments submitted directly 
in writing. The official record is the paper record maintained at the 
address in ``ADDRESSES'' at the beginning of this document.

X. Terms and Conditions Amending Cyanazine Registrations

    On August 2, 1995, EPA accepted DuPont's proposed amendments to its 
cyanazine registrations that effectively phases out the production of 
cyanazine for use in the United States by the end of 1999. The 
amendments also included an incremental reduction of the maximum label 
rates over the course of the phaseout and a requirement for closed cab 
application equipment in 1998. The terms and conditions of the 
amendments apply to all current DuPont cyanazine registrations as well 
as any new registration that the Agency may approve since the 
acceptance of DuPont's proposal, including Griffin's recent conditional 
registrations that were approved by the Agency. As part of the 
requirements for approval of any future cyanazine registrations, any 
registrant must agree to comply with all of the same terms and 
conditions to effectively phaseout cyanazine production for use in the 
United States by end of 1999. The amended terms and conditions that are 
required of all cyanazine registrants appear below.

Terms and Conditions to Amend Cyanazine Registrations

    1. On November 23, 1994, the U.S. Environmental Protection 
Agency (``EPA'') initiated a Special Review under the Federal 
Insecticide, Fungicide, and Rodenticide Act (``FIFRA''), for 
pesticide products that contain a triazine herbicide as an active 
ingredient, Federal Register Notice, Vol. 59, No. 225 (``the Special 
Review''). Cyanazine is one of the triazine products subject to the 
Special Review, and E. I. du Pont de Nemours and Company 
(``DuPont'') is the primary registrant of cyanazine in the United 
States.
    2. EPA's initiation of the Special Review for triazine 
containing products was based on the Agency's preliminary 
determination that triazine products trigger risk criteria that 
indicate these products may present unreasonable risks as described 
in the Notice of Special Review. This preliminary determination by 
EPA with respect to cyanazine, however, is not a finding, conclusion 
or other determination, that cyanazine does in fact present a risk 
to humans or the environment.
    3. The purpose of this letter is to propose a comprehensive 
listing of the terms and conditions of amendments to DuPont's 
cyanazine product registrations. The specific mitigation steps 
proposed in these amendments are designed to reduce the potential 
for the risk criteria being triggered in the future and to 
satisfactorily address EPA's concerns over potential risks as 
described in the Notice of Special Review. DuPont's understanding in 
agreeing to the 

[[Page 8202]]
proposed mitigation steps is that if they are required of all current 
and potential future cyanazine-containing products and 
registrations, including but not limited to DuPont's cyanazine 
products and registrations, they will adequately address EPA's 
concerns that cyanazine products may present risks as described by 
EPA in the Notice of Special Review. It is DuPont's further 
understanding that based on this determination, EPA will proceed to 
conclude the Special Review as to cyanazine as soon as practicable.
    4. DuPont's agreement to the proposed amendments set forth 
herein is not, and shall not be considered as, an admission by 
DuPont that cyanazine used in accordance with DuPont's registrations 
and labels triggers risk criteria as described in the Notice of 
Special Review, or otherwise poses risks to humans or the 
environment.
    5. Cyanazine Risk Mitigation Measures shall be comprised of the 
following steps: (a) The labels of all cyanazine formulated end use 
products released for shipment by a registrantl after July 25, 
1996, for use in the U.S., shall specify seasonal use rates that 
limit the maximum amount of cyanazine active ingredient that may be 
applied on a per acre basis as follows:

    1For the purpose of determining compliance with the proposed 
terms and conditions of amended registrations as set forth in 
paragraph 5., whenever the term ``released for shipment by a 
registrant appears in these amendments, it shall mean the shipment 
of cyanazine formulated end use products, shipped by or at the 
direction of a registrant from the facility at which they are 
finally formulated for distribution, sale and use in the U.S. as 
evidenced by a bill of lading or other verifiable shipping 
documents. The term shall not apply to a) shipments of cyanazine 
formulated end use products by agents, distributors, or dealers who 
receive and further distribute cyanazine products to customers, or 
b) to cyanazine technical products shipped within the U.S. for 
formulation into end use products, or c) to shipments of cyanazine 
technical or formulated end use products for export. Any formulated 
end use product containing cyanazine technical products and 
registered for use in the U.S. shall be subject to the terms and 
conditions of paragraph 5 of this letter.
---------------------------------------------------------------------------

    FOR USE: MAXIMUM SEASONAL USE RATE CAP (AI/ACRE):
Beginning Jan. 1, 1997 5 lbs per acre
Beginning Jan. 1, 1998 3 lbs per acre
Beginning Jan. 1, 1999 1 lb per acre
    (b) Subject to all the terms and conditions of these amendments, 
this letter shall serve as DuPont's request, pursuant to FIFRA, that 
EPA accept the voluntary cancellation of all of DuPont's existing 
registrations for formulated end use products containing cyanazine 
to become effective December 31, 1999. The cancellation date of 
December 31, 1999, shall become a part of the terms and conditions 
of DuPont's registrations for formulated end use products that 
contain cyanazine.
    (c) The labels of all cyanazine products released for shipment 
by a registrant after July 25, 1996, for use in the U.S., shall 
specify that closed cab application will be required for 
applications to be made during or after the 1998 use season.
    (d) No cyanazine formulated end use products registered for use 
in the U.S. shall be released for shipment by a registrant after 
December 31, 1999.
    (e) EPA shall authorize existing stocks of all cyanazine 
formulated end use products that have been released for shipment by 
a registrant of such products on or before December 31, 1999, to 
continue to be distributed and sold in the channels of trade in 
accordance with their labels through September 30, 2002. EPA shall 
authorize the continued use of such existing stocks in accordance 
with their labels through December 31, 2002. Labels of all cyanazine 
formulated end use products released for shipment by a registrant 
after July 25, 1996, shall bear the following statements: ``This 
product may not be sold or distributed after September 30, 2002'' 
``This product may not be used after December 31, 2002.''
    (f) The public will have advance notification of the voluntary 
cancellation of DuPont's cyanazine formulated end use registrations 
and the existing stocks provisions provided for herein as part of 
the conclusion of the Special Review, and DuPont shall have no 
obligation to recover or recall any cyanazine products, or to 
reimburse, or otherwise compensate or provide additional notice to 
any purchaser or other party in connection with or as a result of 
the voluntary cancellation provided for herein.
    (g) cyanazine technical products released for shipment by a 
registrant after July 25, 1996, shall bear labels stating that any 
formulated end use products that are made from the technical 
products and that are registered for use in the U.S., shall be 
subject to the terms and conditions of cyanazine registrations set 
forth in paragraph 5 of this letter.
    6.(a) It is DuPont's understanding that upon its submission to 
EPA of a signed copy of this letter proposing amendments to its 
registrations, EPA will commence such steps as are necessary to 
approve finally the amendments and to conclude the Special Review of 
cyanazine, without requiring further mitigation steps by DuPont, and 
that EPA will complete such final Agency action, including any 
public comment or required notice to other federal agencies, as soon 
as practicable. In the event EPA is unable to so approve the 
amendments or to finally conclude the Special Review, for whatever 
reason, or if after August 2, 1995, and prior to the date EPA 
finally approves these amendments and finally concludes the Special 
Review, another party obtains a cyanazine registration that does not 
contain the terms and conditions set forth in these amendments, for 
whatever reason, these amendments may, at DuPont's election, be 
withdrawn and be without effect, and the current terms and 
conditions of DuPont's cyanazine registrations shall remain in 
effect. In such event, DuPont will retain all of its rights to 
participate fully in the Special Review, or any Agency or judicial 
review of the same, or to contest any regulatory action that may be 
initiated against its products and registrations, pursuant to FIFRA 
or other applicable laws and regulations, as it deems appropriate.
    (b) In the event another party obtains a registration of a 
cyanazine product that does not require the terms and conditions of 
registration as specified in this letter, including cancellation as 
of December 31, 1999, or said terms and conditions are proposed or 
imposed upon another party's registrations, but are stayed or 
enjoined in whole or in part by the Agency or any court, EPA agrees 
to permit DuPont to continue its registrations in effect beyond 
December 31, 1999, and/or amend its cyanazine registrations, on a 
specific use and/or site specific or use rate basis, in order to 
delete any term or condition of registration set forth in this 
letter that is not required of the other party or as a term or 
condition of that party's registration, and to make such other 
amendments to its cyanazine registrations, including but not limited 
to adding new uses or application methods, as are necessary so that 
DuPont's cyanazine registrations may contain the same terms and 
conditions as are contained in the other party's registrations. Any 
such amendments are to be accomplished in accordance with the 
requirements of FIFRA.
    7. On April 16, 1992, EPA issued a Data Call In for cyanazine 
(the ``DCI''). DuPont has completed and submitted all of the studies 
requested in the DCI. EPA agrees that DuPont has submitted all of 
the studies requested by the DCI, and that EPA will not request 
further data from DuPont in connection with said DCI. Nothing 
contained in these amendments shall be interpreted as restricting 
EPA's authority to issue a future Data Call In, or otherwise to 
regulate cyanazine registrations pursuant to FIFRA, should the 
Agency determine that there is significant new evidence about 
potential unreasonable risks to the environment presented by use of 
products containing cyanazine. DuPont shall retain all of its rights 
under FIFRA and other applicable laws and regulations to challenge 
any such action by EPA.
    8. Upon EPA's final acceptance of these amendments, and the 
Agency's final action concluding the Special Review in accordance 
with the amendments and understandings set forth herein, DuPont 
agrees to waive its rights to challenge EPA's final action on the 
Special Review, or the terms and conditions of label amendments that 
are required by these amendments, in any court or administrative 
forum, and agrees not to assist or encourage any other party to 
challenge EPA's final actions. Except as expressly set forth in 
these amendments, DuPont shall retain all of its rights under FIFRA, 
and other applicable laws and regulations, to challenge any action, 
proceeding or determination by EPA, or to challenge or intervene in 
any action by or involving a third party, with respect to the 
registration of DuPont's or any other party's cyanazine products.

XI. References

    1. U.S. Environmental Protection Agency. Notice of Receipt of 
Requests to Voluntarily Cancel Certain Registrations. Federal Register 
Notice (60 FR 56333). November 8, 1995.
    2. U.S. Environmental Protection Agency. Atrazine, Simazine, and 
Cyanazine; Notice of Initiation of Special Review. Federal Register 
Notice (59 FR 60412). November 23, 1994.

[[Page 8203]]

    3. U.S. Environmental Protection Agency. Letter from Lynn R. 
Goldman to Jane D. Brooks, Dupont Agricultural Products. August 2, 
1995.
    4. U.S. Environmental Protection Agency. Notice of Pesticide 
Registration. November 6, 1995.
    5. U.S. Environmental Protection Agency. Notice of Pesticide 
Registration. September 18, 1995.
    6. U.S. Environmental Protection Agency. Notice of Pesticide 
Registration. February 8, 1996.
    7. U.S. Environmental Protection Agency. Notice of Pesticide 
Registration. February 9, 1996.
    8. U.S. Environmental Protection Agency. Notice of Pesticide 
Registration. February 12, 1996.
    9. U.S. Environmental Protection Agency. Memorandum from Denise 
Keehner, Office of Pesticide Programs, Environmental Fate and Effects 
Division. Transmittal of EFED Review of Comments Including DuPont's on 
the PD 1 Related to Ground Water and Surface Water for Cyanazine. 
November 3, 1995.
    10. DuPont Agricultural Products. Letter from Tony E. Catka. 
``Cyanazine Mixer/Loader/Applicator Occupational Cancer Risk 
Estimates.'' October 19, 1994.
    11. U.S. Environmental Protection Agency. Memorandum from Olga 
Odiott, Office of Pesticide Programs, Health Effects Division. 
``DuPont's Cyanazine Occupational Exposure Estimates.'' October 26, 
1995.
    12. U.S. Environmental Protection Agency. Biological and Economic 
Assessment of the Cyanazine Phaseout. February 9, 1996.

    Dated: February 26, 1996.
Lynn R. Goldman,
Assistant Administrator for Prevention, Pollution and Toxic Substances.

[FR Doc. 96-4963 Filed 2-29-96; 8:45 am]
BILLING CODE 6560-50-F