2 I NTRODUCTION

This is the Environm ental Protection Agency’s (EPA or the Agency ) Final Work Plan (FWP) for the registration review of dazomet . This work plan addresses public comments received concerning the Preliminary Work Plan (PWP) , which was posted in the dazomet registration review docket (EPA

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- 0080 ). Dazomet is a non

- selective soil fumigant with fungicidal, herbicidal, and nematicidal properties registered for use as a pre

- plant soil fumigant for strawberries and tomatoes in California only, and nationally for non

- bearing crops and golf course

turf. Dazomet is also an active in gredient in a variety of antimicrobial products. After application dazomet breaks down quickly to the primary toxic degradate, methyl isothiocyanate (MITC) gas.

MITC is also a registered pesticide, is highly volatile

, and is responsible for the biocidal pr operties of this fumigant. The MITC case is addressed in a separate Preliminary Work Plan, located in the MITC docket (EPA

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- 0242).

The Agency is implementing the registration review program pursuant to Section 3(g) of the Federal Insecticide, F ungicide, and Rodenticide Act (FIFRA), and will review each registered pesticide every 15 years to determine whether it continues to meet the FIFRA standard for registration. Changes in science, public policy, and pesticide use practices occur over time. The registration review program is intended to make sure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to meet the statutory standard. The public phase of registration review begins whe n the initial docket is opened for each case.

Informatio n on this program is provided on the Agency’s website

. 1

The FWP begins with any updates since the PWP was issued. Next is a summary of substantive

comments received during the public comment period for the PWP concerning anticipated data

needs

, expected risk assessments, or the estimated timeline identified in the PWP

, and a summary of the Agency’s response s to th o se comments

. This section is followed by registration

review planned data needs, risk assessments expected to be conducted , and the projected registration review timeline for dazomet

. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

The Agency identified existing adsorption/desorption and leaching studies (83 5.12 30 and 835.1240), so these studies will not be required in registration review. The seedling emergence study on MITC (850.4100) was incorrectly captured as “in review” in the PWP , but should have been listed as a new registration review requirement. The a ctivated s ludge r espiration i nhibition (ASRI) study ( 850.3300 ) was identified as a data need in the ecological problem formulation but was not captured in the data needs table in the dazomet PWP. The planned data needs in table 1 have been updated ac cordingly.

There are no additional updates on dazomet since the PWP.

1 http://www.epa.gov/oppsrrd1/registration_review/3 SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60

- day public comment period on the Dazomet Preliminary Work Plan , which opened on September 25, 2013 and closed on November 25 , 2013 the Agency received eight unique p ublic comments. One of those comments includes a mass comment campaign from the Pesticide Action Network of North America (PANNA) which received 5

, 645 signatures , and requests the Agency re

- evaluate risk assessment levels of concern and buffer zone distances imposed by the 2008 reregistration eligibility decision. Comments were also submitted by the registrant, agricultural associations, non

- profit organizations, and one state agriculture department . The comments a ddress the registration review process and utility of soil fumigants in agriculture

. The Agency considered the issues and concerns raised by each of the eight unique comments submitted, but the registration review timeline, data

- requirements, and anticipate d risk assessment needs did not change as a result of these comments. In the PWP, EPA also solicited comments on the specific topics of environmental justice , water quality concerns , and trade irritants, but no comments or information were received on those issues. Public comments in their entirety are located in dazomet docket, EPA

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- 2013

- 0 0 80 . EPA’s responses to those public comments are in Response s to Public Comments on the Dazomet Preliminary Work

Plan , which is also located in the dazomet docket.

PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for dazomet based on the Problem Formulation for the Ecological Risk and Drinking Water Exposure Assessments to be Conducted in Support of the Registration Review of Dazomet and Dazomet Human

- Health Assessment Scoping Document in Support of Registration Review , and Public Comments on the Dazomet Preliminary Work Plan

. With the exception of removing the adsorption/desorption studies (835.1230 and 835.1240), the planned data needs have not changed from what was included in

the PWP

.

Table 1: Planned D ata Needs for the Dazomet Registration Review

Guideline

Number 2 Stu dy Title 2 Test Material Estimated

Timeframe

(Months from receipt of DCI)

Anticipated D ata Needs for the Parent D azomet (for conventional uses of dazomet)

850.2100 Avian oral toxicity (passerine) TGAI 12
Anticipated D ata Needs for the Parent D azomet (for antimicrobial uses only)

875.1700 Product use information TEP 12

2 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850

– Ecological Effects Tests

– including renumbering and other designations or changes for some guideline studies. See “Final Test Guidelines; OCSPP 850 Series; Notice of A vailability” 77 FR 38282, June 27, 2012. http://www.regulations.gov/#!documentDetail;D=EPA

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- 0154

- 00284 Table 1: Planned D ata Needs for the Dazomet Registration Review

Guideline

Number 2 Stu dy Title 2 Test Material Estimated

Timeframe

(Months from receipt of DCI)

875.1200 D ermal exposure for open pour mixing/loading paint (occupational) and applying paint (airless sprayer and

brush/roller ; occupational and residential ) TEP 24

875.2400 Post

- application dazomet dermal exposure for finger painting TEP 24

Anticipated Data Needs for the Degradate MITC (for conventional uses of dazomet)

850.6100 Environmental chemistry methods and associated independent laboratory v alidation s for air, soil, and

water MITC 12

850.4100 Seedling emergence (Tier II) MITC 12

835.4300 Aerobic aquatic metabolism MITC 24

Non

guideline Honey bee vapor exposure MITC 24

850.1400 Freshwater fish early

- life stage MITC 12

Anticipated Data Needs for the Degradate MITC (for antimicrobial uses of dazomet only)

875.1400 Inhalation exposure for open pour mixing/loading paint (occupational) and applying paint (airless sprayer and

brush/roller ; occupational and residential ) MITC 24

875.2400 Post

- application dermal exposure ( for painted rooms) MITC 24

850.3300 3 Activated Sludge Respiration Inhibition (ASRI) MITC 12

3 EPA has a published final guidance for this study : http://www.regulations.gov/#!documentDetail;D=EPA

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OPPT

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- 0154

- 0021 . OECD Test Guideline 209 can also be used as guidance for this study, available online at http://www.oecd

- ilibrary.org/content/book/9789264070080

- en

. The results of the Activated Sludge Respiration Inhibition Test (ASRI) expected to be required will determine which of these four biodegradation tests would be anticipated to be required. If the ASRI test EC50 is less than or equal to 20 mg/L, then either the (i) Biodegradation in Activated Sludge Study or (ii) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Un its or (iii) the Porous Pot Test would be anticipated to be required. If the ASRI test EC50 is greater than 20 mg/L, then the DCI expected to be issued would provide that the registrant would choose to conduct either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready Biodegradability study is conducted and passes, then no further testing would be expected to be require d. If, however, the antimicrobial fails the Ready Biodegradability study, then the a) Biodegradation in Activated Sludge or b) Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units, or c) the Porous Pot study would be expected to be requir ed.5 Table 1: Planned D ata Needs for the Dazomet Registration Review

Guideline

Number 2 Stu dy Title 2 Test Material Estimated

Timeframe

(Months from receipt of DCI)

835.3110 4 Ready Biodegradability MITC 12

835.3220 5 Porous Pot Test MITC 12

835.3280 6 Simulation Tests to Assess the Biodegradability of Chemicals Discharged in

Wastewater MITC 12

835.3240 7 Simulation Test

– Aerobic Sewage Treatment: A. Activated Sludge Units MITC 12

Outstanding Data Requirements from GDCI

- 035602

- 28850 8 (2010 Soil Fumigant Dazomet DCI)

835.8100 Field volatility from soil TEP In review

850.1025 Oyster acute toxicity (shell deposition) MITC In review

850.1035 Mysid acute toxicity MITC In review

850.1075 Fish acute toxicity, freshwater and marine MITC In review

850.2300 Avian reproduction test TGAI In review

850.3020 Honey bee acute toxicity MITC Due April 2014

850.4150 Vegetative vigor (Tier II) MITC In review

850.4400 Aquatic plant growth toxicity (Tier II) MITC In review

870.4200 Carcinogenicity MITC Due April 2014

4 EPA has a published final guideline for this study: http://www.regulations.gov/#!documentDetail;D=EPA

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OPPT

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- 0152

- 0017 . The biodegradation study anticip ated to be required is based on results of an Activated Sludge Respiration Inhibition test

. 5 EPA has a published final guideline for this study: http://www.regulat ions.gov/#!documentDetail;D=EPA

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OPPT

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- 0152

- 0024 . The biodegradation study anticipated to be required is based on results of an Activated Sludge Respiration Inhibition test

. 6 EPA has a published final guideline for this study: http://www.regulations.gov/#!documentDetail;D=EPA

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OPPT

- 2009

- 0152

- 0036 . The biodegradation study anticipated to be required is based on results of an Activated Sludge Respiration Inhib ition test

. 7 EPA has a published final guideline for this study: http://www.regulations.gov/#!documentDetail;D=EPA

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OPPT

- 2009

- 0152

- 0034 . The biodegradation study anticipated to be required is based on results of an Activated Sludge Respiration Inhibition test

. 8 The studies listed in this section were previously required through a generic data call

- in issued in March 2010 and

are still outstanding. These studies will not be included in the anticipated Registration Review DCI because they are already required through the earlier DCI.6 Table 1: Planned D ata Needs for the Dazomet Registration Review

Guideline

Number 2 Stu dy Title 2 Test Material Estimated

Timeframe

(Months from receipt of DCI)

870.3700 Prenatal developmental toxicity study MITC In review

870.3800 Reproduction and fertility effects MITC Due April 2014

870.6200 Neurotoxicity screening battery MITC In review

Non

guideline (numbered

as SS

- 2 on

the

dazomet DCI) Avian acute inhalation

MITC In review

Outstanding Data Requirements from GDCI

- 035602

- 29024 9 (2010 Antimicrobial Dazomet DCI 10 )

875.1200 Dermal Exposure

- Indoor TEP In review

875.1400 Inhalation Exposure

- Indoor MITC Extension requested*

875.1600 Application exposure monitoring data reporting TEP Extension requested*

875.1700 Product Use Information TEP Extension requested*

875.2500 Inhalation Exposure MITC In review

875.2700 Product Use Information TEP Extension requested*

875.2800 Description of human activity TEP Extension requested*

875.2900 Data reporting and calculations TEP Extension requested*

850.1025 Oyster acute toxicity (shell deposition) MITC In review

850.1035 Mysid acute toxicity MITC In review

9 The studies listed in this section were previously required through a generic data call

- i n issued in March 2010 and

are still outstanding. These studies will not be included in the anticipated Registration Review DCI because they are already required through the earlier DCI.

10 The exposure and air concentration monitoring data required by the 2010 antimicrobial dazomet DCI is to support

the following dazomet uses identified by the 2009 Amended Dazomet RED. These uses include: 1) a treatment during the production of pulp and paper; 2) a materials preservative treatment for paper coatings, non

- food adhesives, epoxy flooring compounds, slurries, and high viscous suspensions; 3) a biocide treatment during petroleum operations; 4) a biocide treatment in recirculating cooling water systems; and 5) a remedial wood treatment to utility poles.7 Table 1: Planned D ata Needs for the Dazomet Registration Review

Guideline

Number 2 Stu dy Title 2 Test Material Estimated

Timeframe

(Months from receipt of DCI)

850.1075 Fish acute toxicity, freshwater and marine MITC In review

860.1520 Processed Food/Feed (paper manufacturing

processes TEP In review

870.3700 Prenatal developmental toxicity study MITC In review

TGAI = technical grade active ingredient; TEP = typical end

- use product ; * After the PWP was issued, antimicrobial dazomet registrants submitted an updated extension request, which is currently under review.

RISK ASSESSMENTS FOR REGISTRATION REVIEW

During registration review, t he Agency anticipates the need to conduct a comprehensive ecological risk assessment, including an endangered species assessment, for all uses of dazomet. For human health, EPA anticipates the need to conduct revised occupational and bystander risk

assessments during registration review for conventional uses, and occupational and residential

assessments for antim icrobial uses during registration review

. If toxicological endpoints or points of departure are revised based on the data that are required for registration review

, they

will be considered in the new assessment s
, as well as any changes to the standard ope rating

p rocedures or default exposure assumptions

.

Table 2 below summarizes the planned registration review risk assessments based on the EFED

Problem Formulation and HED Scoping Document and the planned assessments have not changed from what was included in the PWP

.

Table 2 : Anticipated Risk Assessments for the D azomet Registration Review

Type of Risk Assessment Conduct? Notes

Eco logical and Environmental Fate Comprehensive ecological (species to be assessed include terrestrial and aquatic organisms), including endangered species Y Since dazomet rapidly hydrolyzes to MITC, potential exposure to aquatic receptors is primarily to MITC via surface runoff; consequently, the toxicity data for MITC will be used to assess risk to fish, aquatic invertebrates, and aquatic plants. Terrestria l exposure to birds, mammals, invertebrates can occur through consumption of dazomet granules and/or by

inhalation of MITC.

Incidents Will check for updates For a discussion of reported ecological incidents for dazomet, see page 16 of the Problem Formulation.

Human Health8 Dietary

Food N T he uses of dazomet on strawberries and tomatoes (California only) are considered non

- food uses, since there is no reasonable expectation of finite residues in/on food crops when dazomet is used as a pre

- plant fumigant for the labeled use sites . An assessment is not anticipated in registration review

. Drinking water N Based on environmental fate data, the residual contents in soils, and monitoring data, the Agency does not expect MITC to adversely impact the drinking water sources such as surface water and ground water , so an assessment is not anticipated in

reg istration review

.

Occupational Handlers (mixers, loaders, applicators) Y For soil fumigant and antimicrobial uses, updates to handler risk assessments are anticipated.

Post

- application Y An updated occupational post

- application risk assessment for some antimicrobial uses is anticipated.

N Based on re

- entry restrictions specified by the 2009 amended RED for the conventional uses of dazomet, the Agency does not expect risk to re

- entry workers to exceed the Agency’s level of concern.

Residential

Handlers Y For antimicrobial uses only, additional residential handler dermal and inhalation exposure data are required and will be reviewed and incorporated in the risk assessment in registration review.

Post

- application Y For antimicrobial uses only, additional p ost

application dermal exposur e data are required and will be reviewed and incorporated in the risk assessment in registration review.9 Bystander Y For soil uses, there is the potential for residential bystander (anyone not involved in the application) inhalation exposure to MITC after a soil fumigation application of dazomet

. A revised residential risk assessment is anticipated in registration review to update risk to bystanders during and following soil fumigant uses of dazomet products.

Additionally, the Agency anticipates updating the fumigant factors document, which provides a discussion of values and parameters used as the basis

for buffer zone reduction credits as well as for establishing Good Agricultural Practices (GAPs) for the fumigants. Buffer zones and GAPs were sp ecified by the 2009 amended RED as measures to mitigate occupational and bystander risk.

Other Aggregate N E valuates the combined risk from dietary and residential exposures. No dietary risk is anticipated from dazomet. Therefore, an aggregate assessmen t is not anticipated.

Cumulative N Dazomet is not a member of a cumulative group, so no cumulative risk assessment is planned

Tolerances N Currently labeled d azomet use as a pre

- plant soil fumigant is considered non

- food, so there are no

tolerances established for this chemical.

Incidents Will check for updates For a discussion of reported human incidents for

dazomet , see page 8 of the Scoping Document and

Dazomet: Review of Human Incidents

.

TIMELINE

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

review in Table 3 below

. The projected timeline has been updated since the PWP to reflect the lengthening of the timeframe between posting of the draft risk assessment and the proposed

dec ision by one quarter.

Table 3 : Projected Dazomet Registration Review Timeline

Activities Estimated Dat e Opening the Docket Open Docket and 60

- day Public Comment Period September 2013

- Completed

Close Public Comment November 2013

- Completed

Case Development

Final Work Plan February 2014

- Completed10 Table 3 : Projected Dazomet Registration Review Timeline

Activities Estimated Dat e Issue DCI 2014 April

- June

Data Submission 2016 April

- June

6 0

- day Public Comment Period for Draft Risk

Assessments 11 2017 Oct.

– Dec.

Registration Review Decision

60

- day Public Comment Period for Proposed Registration Review Decision 2018

– July

- Sept.

Registration Review Decision and Begin Post

- Decision

Follow

- up 2019

Total (years) 6

NEXT STEPS

As noted previously, the Agency plans to require several environmental fate, ecological effects,

and human health studies for dazomet through a D ata C all

- I n Notice , expected to be issued by

June 2014

.

11 The regulations governing Registration Review generally require the Agency to provide a public comment period

of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pesticides, t he Agency plans to provide a 60 ca lendar day public comment period generally for draft risk assessment s

.