2 I NTRODUCTION

This is the Environm ental Protection Agency’s (EPA or the Agency ) Final Work Plan (FWP) for the registration review of aluminum phosphide and magnesium phosphi d e (hereafter referred to as “metal phosphides”) and phosphine . This work plan addresses public comments received concerning the Preliminary Work Plan (PWP) , which was posted in the metal phosphide and phosphine registration review docket (EPA

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- 0081 ). Phosphine is a colorless gas registered for use against stored

- product insect pests and vertebrate pests, mainly rodents. It is formulated as a pressurized gas and it is also the a ctive ingredient for the metal phosphides. The

metal phophides are formulated as impregnated materials, pellets/tablets, and granules which release phosphine gas upon exposure to atmospheric moisture.

The Agency is implementing the registration review program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered pesticide every 15 years to determine whether it continues to meet the F IFRA 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 when 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 update s 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 the metal phosphides and phosphine

. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

There are no updates on the metal phosphides and phosphine since the PWP.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60

- day public comment period on the Aluminum Phosphide, Magne sium Phosphide, and Phosphine Preliminary Work Plan , which opened on September 25, 2013 and closed on November 25, 2013 , the Agency received 17 public comments . Comments were submitted by a registrant, fumigant applicators, and non

- profit organizations

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

- requirements, and anticipate d risk assessment needs did not change as a result of these comments as outlined in the final work plan. In the PWP, EPA also solicited comments on the specific topics of environmental justice, water quality concerns , and trade irritants, but no

comments o r information were received on those issues.

1 http://www.epa.gov/oppsrrd1/registration_review/3 The comments address the registration review process and utility of fumigants in commodity and structural fumigation. Public comments and EPA responses in their entirety are located in the docket, EPA

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.

• Summarized public comments and Agency responses of a broad regulatory nature are in

the Responses to Public Comments on the Aluminum Phosphi d e , Magnesium Phosphide and Phosphine Preliminary Work Plan.

• Comments and responses related to the an ticipated ecological risk assessment or data

needs are in the Responses to Public Comments on the Aluminum Phosphi d e , Magnesium Phosphide and Phosphine Problem Formulation

.

• Comments r elevant to the anticipated human health risk assessment or data needs are in

the Response to Public Comments on the Preliminary Work Plan (PWP) for Aluminum Phosphide, Magnesium Phosphide, and Phosphine

.

PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for the metal phosphides and phosphine based

on the Registration Review: Preliminary Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for Aluminum Phosphide, Magnesium Phosphide, and Phosphine ; Phosphide (Al, Mg) and Phosphine:

Human

- H ealth Assessment Scoping Document Supporting Registration Review

, and the Agency’s response to comments documents discussed in the previous section of this document

.

The planned data needs have not changed from what was included in the PWP

.

Table 1: Planned D ata Needs for th e Aluminum Phosphide, Magnesium Phosphide, and Phosphine Registration Review

Guideline

Number 2 Study Title 2 Test Material Estimated

Timeframe

(Months from receipt of DCI)

Anticipated D ata Needs for the Parent Aluminum Phosphide, Magnesium Phosphide, and Phosphine

875.1700 Product use information TEP 12

875.1400 Inhalation exposure for applicators TEP 24

875.2500 Post

- application inhalation exposure 3 TEP 24

Non

Guideline Extended one

- generation reproduction study via

inhalation route TGAI 36

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

– Ecological Effects Tests

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

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3 This study is needed to assess post

- application exposures for workers within and near structural fumigation facilities/operations or who work with treated commodities/materials.4 Table 1: Planned D ata Needs for th e Aluminum Phosphide, Magnesium Phosphide, and Phosphine Registration Review

Guideline

Number 2 Study Title 2 Test Material Estimated

Timeframe

(Months from receipt of DCI)

Non

Guideline Special acute inhalation study TGAI 12

Non

Guideline Ambient air monitoring study TEP 36

Non

Guideline Monitoring data on fumigated commodities TEP 24

Non

Guideline Terrestrial plant toxicity (vegetative vigor; vapor exposure) TGAI 12

Non

Guideline Avian acute inhalation toxicity TGAI 24

Non

Guideline Honeybee acute vapor exposure study TGAI 24

TGAI = technical grade active ingredient; TEP = typical end

- use product ;5 RISK ASSESSMENTS FOR REGISTRATION REVIEW

During registration review, t he Agency will conduct a comprehensive ecological risk assessment, including an endangered species assessment, for all uses of the metal phosphides and phosphine

. For human health, EPA will conduct revised dietary, residential

, and occupational risk

assessment s 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 asses sment s
, as well as any changes to the standard operating 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

. T he planned assessments have not changed

from what was included in the PWP

.

Table 2: Planned Risk Assessments for the Aluminum Phosphide, Magnesium Phosphide, and Phosphine 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 The stressors of concern will be the metal phosphides and phosphine

. Phosphine released from structures or

within burrows co mprise the primary exposure pathways of concern for terrestrial organisms. Aquatic exposure to phosphine is assumed to be minimal. Terrestrial (above ground) and aquatic exposure to the metal phosphides is not expected.

Incidents Will check for updates For a discussion of reported ecological incidents for the metal phosphides and phosphine, see page 12 of

the Problem Formulation.

Human Health Dietary

Food Y A new dietary exposure and risk assessment may be required during Registration Review to incorporate potential changes to the phosphine toxicological points of departure ( PODs )

. Drinking water N Given the use pattern and the physical/chemical properties of the metal phosphides and phosphine,

there is a low exposure potential for ground and

surface water

. Occupational Handlers (mixers, loaders, applicators) Y A new occupational handler risk reassess m ent will incorporate new data

, updated PODs, and

, to the extent that they are available, policies currently under development regarding assessment of fumigant

chemicals.6 Post

- application Y A new occupational post

- application risk

reassess m ent will be undertaken using new data

, updated PODs

, and to the extent that they are available, policies currently under development regarding assessment of fumigant chemicals.

Residential

Handlers N The metal phosphides and phosphine are restricted use pesticides, so residential handlers are prohibited

from applying these products.

Post

- application N Metal phosphide and phosphine exposure to

occupants of fu m i gated structures is ex p ected to be

n egli g ible g iven proper aeration procedures

. Bystander Y Bystander risk (anyone not part of the fumigation)

from phosphine emissions from treated commodities

and structures will need to be evaluated based on label prescribed use conditions, and if the PODs or uncertainty factors (UFs) change based on acute toxicological data identified

. Other Aggregate Y E valuates the combined risk from dietary and residential exposures.

Cumulative N The metal phosphides and phosphine are not members of a cumulative group, so no cumulative risk assessment is planned.

Tolerances Y Tolerances are established for residues of the fumigants aluminum phosphide, magnesium phosphide and phosphine gas in 40 CFR §180.225.

Incidents Will check for updates For a discussion of reported human incidents for the metal phosphides and phosphine see page 12 of the Scoping Document and the Aluminum Phosphide, Magnesium Phosphide and Phosphine: Review of

Human Incident s.

TIMELINE

EPA has created the following es timated timeline for the completion of the metal phosphides and phosphine 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 decision by one quarter.

Table 3: Registration Review for Phosphide, Magnesium Phosphide, and Phosphine

– Projected Registration Review Timeline

Activities Estimated Date Opening the D ocket Open Docket and 60

- day Public Comment Period September 2013

– Completed

Close Public Comment November 2013

–7 Table 3: Registration Review for Phosphide, Magnesium Phosphide, and Phosphine

– Projected Registration Review Timeline

Activities Estimated Date Completed Case Development

Final Work Plan March 2014

– Completed

Issue DCI 2014 April

- June

Data Submission 2017 April

- June

60

- day Public Comment Period for Draft Risk Assessments 4 2018 Oct.

– Dec.
Registration Review Decision

60

- day Public Comment Period for Proposed Registration Review

D ecision 2019

– July

– Sept.

Registration Review D ecision and Begin P ost

- D ecision F ollow

- up 2020

Total ( years ) 7

NEXT STEPS

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

and human health studies for the metal phosphides and phosphine through a D ata C all

- I n Notice

, expected to be issued in June 2014

.

4 The regu lations 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, the Agency plans to provide a 60 calenda r day public comment period generally for draft risk assessments.