United States Prevention, Pesticides
Environmental Protection and Toxic Substances May 2009
Agency (7508P)
Amended Reregistration Eligibility
Decision (RED) for the
Methyldithiocarbamate Salts (Metam
sodium, Metam-potassium) and
Methyl Isothiocyanate (MITC)
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Amended Reregistration Eligibility Decision (RED) Document
for
Methyldithiocarbamate Salts (Metam-sodium, Metam-potassium) and Methyl
Isothiocyanate (MITC)
ListB
CaseNos. 2390 and 2405
Approved by:
Richard P. Keigwin, Jr., Director
Special Review and Reregistration Division
Date:
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Glossary of Terms and Abbreviations
1,3-D
AGDCI
ai
aPAD
ARS
BCF
BEAD
CFR
cPAD
CSF
CSFII
DCI
DEEM
DFR
DNT
EC
EDWC
EEC
EPA
EUP
FDA
FDMS
FIFRA
FFDCA
FMP
FQPA
GAP
GLN
ha
HC
IR
ISCST3
Kd
LCso
LD
50
LOC
1,3-dichloropropene
Agricultural Data Call-In
Active Ingredient
Acute Population Adjusted Dose
Agricultural Research Service
Bioconcentration Factor
Biological and Economic Analysis Division
Code of Federal Regulations
Chronic Population Adjusted Dose
Confidential Statement of Formulation
USDA Continuing Surveys for Food Intake by Individuals
Data Call-In
Dietary Exposure Evaluation Model
Dislodgeable Foliar Residue
Developmental Neurotoxicity
Emulsifiable Concentrate Formulation
Estimated Drinking Water Concentration
Estimated Environmental Concentration
Environmental Protection Agency
End-Use Product
Food and Drug Administration
Federal Docket Management System
Federal Insecticide, Fungicide, and Rodenticide Act
Federal Food, Drug, and Cosmetic Act
Fumigant Management Plan
Food Quality Protection Act
Good Agricultural Practice
Guideline Number
Hectare
Human Concentration
Index Reservoir
Industrial Source Complex Short Term (model)
Dissociation Constant
Median Lethal Concentration. A statistically derived concentration of a
substance that can be expected to cause death in 50% of test animals. It is
usually expressed as the weight of a substance per weight or volume of
water, air, or feed, e.g., mg/1, mg/kg, or ppm.
Median Lethal Dose. A statistically derived single dose that can be
expected to cause death in 50% of the test animals when administered by
the route indicated (oral, dermal, inhalation). It is expressed as a weight
of substance per unit weight of animal, e.g., mg/kg.
Level of Concern
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LOAEL
MATC
MAT
MBAO
MITC
mg/kg/day
mg/L
MST
MOA
MOE
mph
MRID
MSDS
MUP
NOAEL
OECD
OPP
OPPTS
PAD
PCA
PDCI
PDF
PERFUM
PF
PHED
PHI
ppb
PPE
ppm
PRZM/EXAMS
RAC
RED
REI
RfD
RQ
SCI-GROW
SAP
SF
SLC
TGAI
USDA
Lowest Observed Adverse Effect Level
Maximum Acceptable Toxicant Concentration
Micrograms Per Gram
Micrograms Per Liter
Maximum Air Temperature
Methyl Bromide Alternatives Outreach
Methyl Isothiocyanate
Milligram Per Kilogram Per Day
Milligram Per Liter
Maximum Soil Temperature
Mode of Action
Margin of Exposure
Miles Per Hour
Master Record Identification Number. EPA's system for recording and
tracking studies submitted.
Material Safety Data Sheet
Manufacturing-Use Product
No Observed Adverse Effect Level
EPA Office of Pesticide Programs
EPA Office of Prevention, Pesticides, and Toxic Substances
Population Adjusted Dose
Percent Crop Area
Product-Specific Data Call-in
USDA Pesticide Data Program
Probabilistic Exposure and Risk Model for Fumigants
Protection Factor
Pesticide Handler's Exposure Data
Pre-harvest Interval
Parts Per Billion
Personal Protective Equipment
Parts Per Million
Pesticide Root Zone Model/Exposure Analysis Modeling System (Tier II
Surface Water Computer Model)
Raw Agriculture Commodity
Reregi strati on Eligibility Decision
Restricted Entry Interval
Reference Dose
Risk Quotient
Tier I Ground Water Computer Model
Science Advisory Panel
Safety Factor
Single Layer Clothing
Technical Grade Active Ingredient
United States Department of Agriculture
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USGS United States Geological Survey
UF Uncertainty Factor
UV Ultraviolet
WPS Worker Protection Standard
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Table of Contents
Methyldithiocarbamate Salts and Methyl Isothiocyanate Team 8
Abstract 9
I. Introduction 10
II. Chemical Overview 15
A. Chemical Identity 15
B. Use Profiles 16
C. Regulatory History 18
III. Metam-sodium and Metam-potassium Risk Assessments 19
A. General Overview of Soil Fumigants 19
1. Human Health Risk 19
2. Environmental Fate, Ecological Effects and Risks 23
3. Benefits 25
4. 2008 RED Mitigation Impacts 29
B. Overview of Sewer Use Risk 31
C. Overview of Antimicrobial Risk 32
IV. Risk Management and Reregistration Eligibility Decision 33
A. Determination of Reregistration Eligibility 33
B. Public Comments and Responses 36
C. Regulatory Position 37
1. Regulatory Rationale 37
a. Soil Fumigant Uses of Metam-sodium and Metam-potassium 37
1. Use Sites Eligible for Reregistration 38
aa. Bystander Risk Mitigation 43
1. Buffer Zones 44
2. Restriction for Schools and Other Difficult To Evacuate Sites 74
3. Posting 75
bb. Occupational Risk Mitigation for Soil Uses 78
1. Handler Definition 78
2. Handler Requirements 79
3. Dermal Protection for Handlers 80
4. Respiratory Protection for Handlers 84
5. Tarp perforation and removal 92
6. Entry Prohibitions 95
cc. Other Risk Mitigation 101
1. Restricted Use Pesticide (RUP) Classification 101
2. Good Agricultural Practices (GAPs) 102
3. Fumigant Management Plans (FMPs) 112
4. Site Specific Response and Management 119
5. Notice to State Lead Agencies 125
6. Training for Applicators and Training Information for Other Handlers... 126
7. Community Outreach and Education Program 131
8. Ambient Air Monitoring Program 136
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b. Sewer Root Control Use 138
c. Antimicrobial Uses 145
2. Endocrine Disrupter Effects 149
3. Endangered Species Considerations 149
D. Conclusion 149
V. What Registrants Need to Do 149
A. Manufacturing Use Products 150
1. Additional Generic Data Requirements 150
2. Labeling for Manufacturing-Use Products 158
B. End-Use Products 158
1. Additional Product-Specific Data Requirements 158
2. Labeling for End-Use Products 158
Appendix A: Uses Eligible for Reregistration 159
Appendix B: Studies Used to Make the Reregistration Decision 171
Appendix C: Technical Support Documents 172
Appendix D: FMP Template-MeBr Example 175
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Methyldithiocarbamate Salts and Methyl Isothiocyanate Team
Health Effects Risk Assessment
Ruth Allen
Judy Facey
Anna Lowit
Jessica Ryman
Charles Smith
Shalu Shelat, Risk Assessor
Biological and Economic Analysis Assessment
Jonathan Becker
Angel Chiri
Bill Chism
Colwell Cook
David Donaldson
John Faulkner
Monisha Kaul
Andrew Lee
Nikhil Mallampalli
William Phillips, II
Sunil Ratnayake
Elisa Rim
Stephen Smearman
TJ Wyatt
Leonard Yourman
Nicole Zinn
Office of General Council
Andrea Medici
Office of Enforcement and
Compliance
David Stangel
Risk Management
Dirk Helder
Veronique LaCapra
John Leahy
Nikhil Mallampalli
Cathryn OConnell
Karen Santora
Registration Support
Tamue Gibson
Mary Waller
Environmental Fate and Effects Risk Assessment
James Felkel
Faruque Khan
Gabriel Rothman
Risk Management - Antimicrobial Uses
Timothy Dole
Heather Garvie
Diane Isbell
Timothy Leighton
Tim McMahon
Kathryn Montague
Rick Petrie
Cassi Walls
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Abstract
This document presents EPA's amended decision regarding the reregi strati on eligibility
of the currently registered soil, sewer root control, and antimicrobial uses of metam-sodium, the
soil and antimicrobial uses of metam-potassium, and the antimicrobial uses of methyl
isothiocyanate (MITC). This follows the 105-day public comment period on the Reregi strati on
Eligibility Decision provided for stakeholders to have the opportunity to review and provide
comments on issues related to the implementation of the risk mitigation measures. The
Agency's risk conclusions for metam-sodium and metam-potassium have not changed. In
addition, all measures established in the July 2008 RED to reduce risks to bystanders and
workers will still be required. However, the Agency has determined that certain modifications in
how and when some measures will be implemented are appropriate. Products containing metam-
sodium and metam-potassium for these uses are eligible for reregi strati on provided that: (1)
current data gaps are addressed; (2) the risk mitigation measures identified in the document are
adopted; and (3) labels are amended to implement these measures.
Generally, registered metam-sodium and metam-potassium application/fumigation uses
fall into four basic categories that include: (1) use as an agricultural soil fumigant for all food,
feed, and fiber crops; (2) use on golf course turf and for application to small areas of turf and
soil; (3) use as a root-control agent in drains and sewers; and (4) use for a number of
antimicrobial and industrial uses, including treatments for sugar (raw beets and cane sugar)
processing facilities; leather; sewage, sludge, and animal waste; cooling water facilities;
industrial water purification facilities; paints and coatings; petroleum operations; and remedial
wood treatment. MITC is registered as an active ingredient for only one use, as an antimicrobial
agent for remedial wood treatment.
Concurrent to EPA's review of the soil fumigant uses of metam-sodium and metam-
potassium, EPA assessed the risks and developed risk management decisions for four other soil
fumigant pesticides, including: chloropicrin, dazomet, methyl bromide, and a new active
ingredient, iodomethane. Risks of a fifth soil fumigant, 1,3-dichloropropene (1,3-D), were also
analyzed along with the other soil fumigants for comparative purposes; its risk management
decision was completed in 1998. The Agency evaluated these soil fumigants concurrently to
ensure that human health risk assessment approaches are consistent and that risk tradeoffs and
economic outcomes were considered appropriately in reaching risk management decisions. This
review is part of EPA's program to ensure that all pesticides meet current health and safety
standards.
EPA has identified potential human health risks of concern associated with the registered
soil fumigant uses of metam-sodium and metam-potassium from acute inhalation exposure to
handlers, bystanders, and re-entry workers. To reduce these exposures and to address subsequent
risks of concern, EPA is requiring a number of mitigation measures, such as classifying some
metam-sodium and metam-potassium products as restricted use, use-site restrictions, buffer
zones, posting, emergency preparedness and response, monitoring and respiratory protection,
restrictions on the timing of tarp perforation and removal operations, entry prohibitions,
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mandatory good agricultural practices (GAPs), fumigant management plans (FMPs), and training
and outreach programs. Please note that only metam-sodium and metam-potassium soil and
sewer use products and the MITC use for remedial treatment of wood poles and timbers will be
classified as restricted use pesticides.
The Agency has identified slight exceedance of the cancer level of concern to applicators
associated with the registered sewer root control use of metam-sodium. The Agency also has
identified concerns due to potentially harmful downstream effects of metam-sodium on
denitrifying bacteria and the associated disruption to downstream sewage treatment facilities. To
reduce applicator exposures, the Agency is requiring additional personal protective equipment
(PPE), including chemical-resistant gloves, double layer clothing, and a 90% protection factor
respirator approved for MITC. To reduce the potentially harmful effects of metam-sodium on
denitrifying bacteria at downstream sewage treatment facilities, the Agency will be requiring
additional label language requiring notification of downstream wastewater facilities before a
metam application takes place.
The Agency also has identified potential human health risks of concern associated with
the registered antimicrobial uses of metam-sodium, metam-potassium, and MITC. To reduce
these exposures, the Agency is requiring a number of mitigation measures, such as additional
labeling language for remedial wood treatment and amended labeling for the cooling tower and
sewage sludge/animal waste uses. In addition, the Agency will be calling in air concentration
monitoring data for all enclosed facilities that use metam-sodium and metam-potassium.
The Agency is issuing this amended decision document for metam-sodium, metam-
potassium, and MITC, as announced in a Notice of Availability published in the Federal
Register.
I. Introduction
This amends and supersedes the document, "Reregi strati on Eligibility Decision for
Methyldithiocarbamate Salts (Metam-sodium, Metam-potassium) and Methyl Isothiocyanate
(MITC)," published by the U.S. Environmental Protection Agency (hereafter, EPA) on July 16,
2008. That day EPA opened a 60-day public comment period on the implementation aspects of
the risk mitigation measures that were required as conditions of reregi strati on eligibility under
FIFRA. EPA received requests to extend the comment period from the Methyl Bromide Industry
Panel (MBIP), California Specialty Crops Council, the Chloropicrin Manufacturers' Task Force
(CMTF), the National Association of Manufacturers (NAM), the American Nursery and
Landscape Association (ANLA), the California Strawberry Nurserymen's Association, the
Agricultural Retailers Association, the American Forest and Paper Association, and McDermott,
Will, and Emery LLP, on behalf of the Minor Crop Farmer Alliance (MCFA). In response to
these requests, on August 29, 2008, EPA published a notice in the Federal Register extending the
comment period for an additional 45 days. The comment period closed on October 30, 2008.
EPA has completed its review of public comments as well as new scientific data and other
information provided and determined that all measures established in the July 2008 RED to
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reduce risks to bystanders and workers will still be required. The Agency has determined that
certain modifications in how and when some measures will be implemented are appropriate. The
public comments and EPA's responses, as well as other supporting documents, may be found in
the public docket for metam-sodium and metam-potassium (EPA-HQ-OPP-2005-0125) at
www.regulations.gov. EPA has determined that the modifications described herein will achieve
the same protection goals for persons potentially exposed to metam-sodium and metam-
potassium and MITC but with a greater likelihood of compliance, fewer impacts on the benefits
of metam-sodium and metam-potassium and MITC use, and with less uncertainty regarding the
protectiveness of the required measures. Please see table 1 for modification from the 2008 RED
to the 2009 amended soil fumigant REDs.
Note: Washington State University has submitted studies to quantify the flux rate for metam-
sodium and metam-potassium from shank injection applications and from center pivot
applications using a drizzle boom in the Pacific Northwest. These studies were submitted in
April, 2009, and are currently in review. If these studies indicate that the buffer zones for these
types of applications should be modified, the Agency will update the buffer tables prior to
implementation of new labeling related to buffers for metam sodium in 2011. The results of
these studies have not been included in this amended document.
Table 1. Modifications from 2008 to 2009 Amended Soil Fumigant REDs
Mitigation 2008 REDs 2009 Amended REDs
Buffer Zones
Buffer Credits
Structures within
Buffer Zones
Rights of Way
Buffer Overlap
Restriction for
Difficult to Evacuate
Sites
Posting
Buffer zones based on
available data
Credits allowed based on
available data; capped at
50%
Monitor with devices
before reentry
Permission from local
authorities must be granted
if buffers extend onto
rights of way
Buffers may not overlap
1/4 mile restriction around
hard to evacuate areas
including day care centers,
nursing homes, schools;
was to be in effect for the
duration of the buffer zone
period
Posting required at buffer
zones points of entry,
New chloropicrin data support smaller
buffers and increased confidence in safety
New dazomet data support larger buffers
New data support additional credits and an
increase in the cap to 80% for chloropicrin
and methyl bromide, metam-sodium and
metam-potassium, and 40% for dazomet
Monitor for sensory irritation before
reentry
Permission from local authorities is only
required when a sidewalk or permanent
walkway is present
Buffers may overlap; separate applications
by 12 hours and increase emergency
preparedness and response measures
Maintain 1/4 mile restriction but allow a
reduced restricted area of 1/8 mile for
applications with smaller buffers (300 feet
or less); is to be in effect during the
application for 36 hours following the
application
The posting requirement is retained but no
longer requires areas between the entry
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Mitigation
2008 REDs
2009 Amended REDs
Handler Protection
Respiratory
Protection
Tarp perforation and
removal
Entry Prohibitions
Restricted Use
Classification
Good Agricultural
Practices
(GAPs)
Fumigant
Management Plans
(FMPs)
Emergency Response
and Preparedness
where people are likely to
approach, and areas
between these locations
Described tasks that may
only be performed by
handlers and situations
when 2 handlers were
required to be present
while in the buffer zone
Required monitoring
devices to trigger
OO
additional measures
Perforating tarps restricted
to mechanical means only
Entry for non-handlers is
prohibited for the duration
of the entry restricted
period, until tarps have
been removed, or if 14
days has passed
The soil fumigant uses of
metam-sodium and metam
potassium, and MITC use
for remedial treatment of
wood poles and timbers
are required to be classified
as restricted use
Certain GAPs required for
all fumigant applications
FMPs required to be
completed before fumigant
application begins and
post-application summary
report required following
the application
If neighbors are near
buffers they must be
provided with information
or buffer zones must be
areas to be posted
Information required on the signs has been
simplified to encourage reuse of signs
Tasks that may only be performed by
handlers have been updated and clarified
The situations have been clarified
requiring 2 handlers to be present based on
the chemical properties of the different soil
fumigants, and current label statements
Allow sensory irritation properties to
trigger additional measures for MITC and
OO
chloropicrin
Monitoring with devices required to
remove respirators
Monitoring with devices required for
methyl bromide formulations with <20%
chloropicrin
Perforating tarps by hand is allowed for
areas less than 1 acre in size and for flood
prevention activities
No major changes
No change
Some clarifications and refinements have
been made based on stakeholder comments
No major changes. Based on comments an
example of an FMP has been included to
illustrate how the required information
may be presented effectively
Same basic measures
Monitoring required only during peak
emission times of the day; irritation
detection acceptable for MITC and
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Mitigation
2008 REDs
2009 Amended REDs
Notice to SLAs
Applicator Training
Community Outreach
and Education
monitored every 1-2 hours
over 48 hours with
monitoring devices
Applicators required to
provide notice to the
appropriate state/tribal lead
agency before fumigating
to facilitate compliance
assistance and assurance
Certified applicators
required to receive
registrant soil-fumigant
training every year
Registrants required to
develop and implement
community outreach &
education programs along
with information for first
responder in high fumigant
use areas
chloropicrin in lieu of devices; methyl
bromide requires devices
States may determine if they wish to
receive this information
All states required to include strategies for
compliance assistance and assurance for
soil fumigation in their cooperative
agreements
Certified applicators required to receive
registrant soil-fumigant training every
three years
Same basic requirement
The Agency is providing information on
where registrants are required to focus
these efforts
With regard to implementation timing, EPA has determined that most measures can be
efficiently implemented via revised product labels by the 2010 use season for the antimicrobial
uses and the soil fumigant uses. Other measures, in particular those related to buffer zones, will
present greater compliance challenges and will require additional time for EPA to conduct the
necessary outreach, and communication activities with states, tribes, other regulatory partners,
fumigant users, and other stakeholders to facilitate transition. EPA has determined that these
measures will be implemented via revised product labels by the 2011 use season. As a result, all
measures described in this amended RED that are necessary for reregi strati on eligibility will
appear on product labels by 2011. The table below shows the measures that will be implemented
in 2010 and the additional measures that will be implemented in 2011.
Table 2. Implementation Schedule for Soil Fumigant Risk Mitigation Measures
Risk Mitigation Measure
Restricted Use (for soil uses of metam-sodium and
metam-potassium, and MITC use for remedial
treatment of wood poles and timbers only)
New Good Agricultural Practices
Rate reductions
Use site limitations
New handler protections
Tarp cutting and removal restrictions
Extended worker reentry restrictions
Currently
2010
•
•
•
•
•
•
•
2011
•
•
•
•
•
•
•
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Risk Mitigation Measure
Training information for workers
Fumigant Management Plans
First responder and community outreach
Applicator training
Compliance assistance and assurance measures
Restrictions on applications near sensitive areas
Buffer zones around all occupied sites
Buffer credits for best practices
Buffer posting
Buffer overlap prohibitions
Emergency preparedness measures
Currently
2010
•
o
o
0
o
2011
•
•
•
•
•
•
•
•
•
•
•
o = under development
• = adopt completely
The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was amended in 1988
to accelerate the reregistration of products with active ingredients registered prior to November
1, 1984. The amended Act calls for the development and submission of data to support the
reregistration of an active ingredient, as well as EPA's review of all submitted data.
Reregistration involves a thorough review of the scientific database underlying a pesticide's
registration. The purpose of the Agency's review is to reassess the potential risks arising from
the currently registered uses of the pesticide; to determine the need for additional data on health
and environmental effects; and to determine whether or not the pesticide meets the "no
unreasonable adverse effects" criteria of FIFRA.
This document presents the Agency's amended reregistration eligibility decision for all
the registered uses of metam-sodium, metam-potassium, and methyl isothiocyanate. Metam-
potassium and metam-sodium are non-selective fumigants with fungicidal, herbicidal,
insecticidal, and nematicidal properties. Metam-sodium and metam-potassium are converted to
MITC in the environment, particularly in the presence of moisture (such as in soil after
application). It is MITC that performs the fumigating activity. Metam-sodium and metam-
potassium have soil fumigant and antimicrobial uses, metam-sodium is also used as a root
control agent in sewers and drains, and MITC is registered as an antimicrobial agent for treating
wood poles and pilings. Separate risk assessments and analyses were developed for the soil
fumigant, sewer root control, and antimicrobial uses of metam-sodium, metam-potassium, and
MITC. To clearly present EPA's decision regarding these uses, each use will be discussed in
separate sections of this reregistration eligibility decision (RED).
As a result of this review, the Agency has determined that certain uses of (1) metam-
sodium (including use as a pre-plant soil fumigant in certain crops, specified later in this
document, and as a root control agent in sewers and drains, and as an antimicrobial agent to treat
wood poles and timbers and sewage sludge and animal waste); (2) metam-potassium (including
use as a pre-plant soil fumigant in certain crops, specified later in this document, and as an
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antimicrobial agent for treatment of pulp and paper, tanning drum leather applications,
recirculating cooling water systems, and industrial water purification systems); and (3) MITC
(for use as an antimicrobial agent to treat wood poles and pilings) are eligible for reregi strati on
(see Appendix A), provided the risk mitigation measures outlined in this document are adopted,
label amendments are made to reflect these measures (see the label table in Section V of this
document), and data are developed to assess intermediate- and long-term risk to bystanders.
This document consists of five sections. Section I contains the regulatory framework for
reregi strati on and a synopsis of modifications from the July 2008 RED. Section II provides a
profile of the use and usage of the chemical. Section III provides a general fumigant overview
and also the metam-sodium, metam-potassium, and MITC risk assessments as well as benefit
and impact assessments. Section IV presents the Agency's reregi strati on eligibility and risk
management decisions. Section V summarizes label changes necessary to implement the risk
mitigation measures outlined in Section IV. Unless otherwise noted, all Agency references in
this document are available for review in the metam-sodium and metam-potassium docket (EPA-
HQ-OPP-2005-0125) at www.regulations.gov.
II. Chemical Overview
A. Chemical Identity
Both metam-sodium and metam-potassium are the active ingredients that make up
reregi strati on case 2390 for the methyldithiocarbamate salts. The primary degradate of both
metam-sodium and potassium is methyl isothycyanate (MITC), which is the active ingredient
that makes up reregi strati on case 2405.
Table 3. Methyldithiocarbamate Salts & Methyl Isothiocyanate Nomenclature
Chemical Structure:
Empirical Formula:
Common Name:
CAS Registry Number:
OPP Chemical Code:
Case Number:
Technical or
Manufacturing-Use
Registrants
H^N^8' Na+
s
C2H4NS2Na
Metam-sodium
137-42-8
039003
2390
Douglas Products and
Packing Company;
IBC Manufacturing
Co.; Buckman
Laboratories Inc.;
AMVAC Chemical
Corporation; Drexel
H
wr/N^r-^S K+
HjC Y
s
C2H4NS2K
Metam-potassium
137-41-7
039002
2390
Buckman
Laboratories Inc.;
Athea Laboratories
Inc.; Taminco Inc.;
Tessenderlo Kerley,
Inc.
/N^
H3C ^C=S
C2H3NS
Methyl
isothiocyanate
556-61-6
068103
2405
MLP International
(Landis
International, Inc.);
Osmose Utilities
Services, Inc.
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Chemical Co.;
Loveland Products,
Inc.; Taminco Inc.;
BASF Sparks LLC;
Tessenderlo Kerley,
Inc.; Sewer Sciences,
Inc.; Osmose Utilities
Services, Inc.
B. Use Profiles
Pesticide Type:
1. Soil Use
Target pests:
Use patterns:
Formulations:
Methods of Application:
Metam-sodium and metam-potassium are broad-spectrum fumigants
with fungicidal, bactericidal, algicidal, herbicidal, insecticidal,
nematicidal, and antimicrobial properties. They are dithiocarbamate
salts that break down quickly in the environment to the primary toxic
degradate, methyl isothiocyanate. MITC is highly volatile and is
responsible for the fumigant properties of metam-sodium and metam-
potassium.
Metam-sodium and metam-potassium are used on a wide range of
pests including fungi, plants, insects, and nematodes.
Metam-sodium and metam-potassium are registered: (1) as an
agricultural soil fumigant for use on all food, feed, and fiber crops
and (2) for use on golf course turf and for application to small areas
of turf and soil.
Three formulation classes—liquid, soluble concentrate, and ready-to-
use—are registered for metam-sodium and metam-potassium. Most
metam-sodium products are registered for general use. Only the
metam-sodium products registered specifically for use on golf courses
and for use on small areas of turf and soil are classified as "restricted
use." The "restricted use" classification restricts a product, or its uses,
to use by certified pesticide applicators or those working under the
direct supervision of a certified applicator. No metam-sodium
products are intended for use by homeowners.
In agricultural settings, metam-sodium and metam-potassium are
applied through chemigation or with tractor-drawn equipment.
Chemigation methods include sprinkler irrigation (which accounts for
90% of irrigation applications), drip irrigation, flood irrigation, and
furrow irrigation. Tractor-drawn applications are carried out with
various types of shank soil injection, rotary tiller, and spray blade
injection equipment. Drip/trickle irrigation and tractor-drawn
applications can be either tarped or untarped. Applications to smaller
areas can be made with handheld equipment, including sprinkler cans,
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Application Rates:
Annual Usage in the
U.S.:
2. Sewer Use
Target pests:
Use patterns:
Formulations:
Methods of Application:
Application Rates:
3. Antimicrobial Use
Target pests:
Use patterns:
hose proportioners (hose-end sprayers), or power sprayers (handgun
sprayers). Metam-sodium/potassium applications to potting soil may
be made by adding the chemical to soil in a cement mixer or by
spraying it onto a soil stream as soil is ejected from a shredder
The maximum application rate listed on most product labels for
application to ornamentals; turf; and food, feed, and fiber crops is 320
pounds of active ingredient per acre (Ibs ai/A). Tobacco plant beds
have a maximum application rate of 387 Ibs ai/A on most product
labels, but at least one product lists a rate as high as 412 Ibs ai/A. For
small areas of ornamentals, food and fiber crops, seed beds, plant
beds, and lawns, the maximum application rate is 12 Ibs ai/1000
square feet.
Approximately 51-55 million pounds of metam-sodium and 1-2
million pounds of metam-potassium used in the U.S. in 2002.
Metam-sodium is used as a root control agent for use in sewers and
drains.
Metam-sodium is classified as a restricted use product as a root-
control agent in drains and sewers.
Three formulation classes—liquid, soluble concentrate, ready-to-
use—are registered for metam-sodium. All metam-sodium products
for sewer use are classified as restricted use pesticides. The "restricted
use" classification restricts a product, or its uses, to use by certified
pesticide applicators or those working under the direct supervision of
a certified applicator.
In sewer use applications, metam-sodium is applied using a foam
applicator.
For sewers and drains, the maximum application rate is 0.212 Ibs
ai/gallon of solution.
The antimicrobial uses of metam-sodium, metam-potassium, and
MITC are used to control a number of microbiological pests,
including bacteria and fungi.
• Metam-sodium is registered as an antimicrobial agent for: (1)
wood poles/timbers, (2) leather processing (e.g., brine-cured
hides and skins), (3) raw cane and beet sugar processing
facilities, and (4) sewage sludge/animal wastes.
• Metam-potassium is registered as an antimicrobial agent for:
(1) pulp and paper production, (2) leather processing, (3) raw
cane and beet sugar processing facilities, (4) coatings
(protective colloids, emulsion resins, and water-thinned
paints), (5) metalworking cutting fluids and oils, (6)
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petroleum operations, (7) water cooling tower systems, and
(8) industrial water purification systems.
• MITC is registered as an antimicrobial agent for wood poles
and pilings.
Formulations: Two formulation classes—soluble concentrate and ready-to-use—are
registered for metam-sodium and metam-potassium. MITC is
formulated as a solidified-melt, where it is a solid at ambient
conditions and melts and vaporizes at elevated temperatures found
within the pole being treated.
Methods of Application: The antimicrobial uses of metam-sodium, metam-potassium, and
MITC have a number of application methods, including open pour and
manual application of pre-filled tubes of solidified-melt product for
treatment of wood poles and pilings; metering pump for pulp and
paper, leather, cooling water towers, and industrial water purification;
and metered injection for animal waste and sewage sludge treatment.
C. Regulatory History
Metam-sodium (PC Code 039003) and metam-potassium (PC code 039002) are included
in pesticide reregi strati on case number 2390. Currently, there are 39 registered products
containing metam-sodium and 16 registered products containing metam-potassium. Metam-
sodium and metam-potassium are broad-spectrum fumigants with fungicidal, herbicidal,
insecticidal, bactericidal, algicidal, and nematicidal properties.
Metam-potassium was first registered in the United States in 1973 as a fungicide, a
bacteriostat, and a microbicide in a variety of commercial and industrial applications, such as
pulp and paper mills, cooling tower waters, metalworking cutting fluids, and adhesives. In 1994,
the use of metam-potassium expanded to include food and feed uses when used as a soil
fumigant.
Metam-sodium was first registered in the United States in 1975. Metam-sodium is one of
the most widely used agricultural pesticides in the United States and is presently registered on a
wide variety of food and feed crops. Metam-sodium is also registered for a variety of
antimicrobial and industrial uses.
Metam-sodium and metam-potassium are converted to MITC in the environment,
particularly in the presence of moisture. It is MITC that performs the fumigating activity. It is
the volatility of metam-sodium in the environment and the results of metabolism studies in plants
that allow the Agency to conclude that there is no reasonable expectation of finite residues to be
incurred in/on any raw agricultural commodity when these products are applied according to
label directions. Therefore, this fumigant does not require the establishment of food tolerances.
A Phase IV data call-in (DCI) was issued for metam-sodium and metam-potassium in
September 1991 and included data requirements for ecotoxicity, toxicology, environment fate,
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and residue chemistry. Metam-sodium also was included in the October 1995 agricultural
reentry DCI.
Since metam-sodium and metam-potassium are converted to MITC in the environment,
this RED will also include MITC. MITC (PC code 068103) is in case number 2405. Products
containing MITC were first registered in 1984 as a soil fumigant with food and non-food uses.
A Phase IV DCI was issued for MITC in July 1991 and included data requirements for
ecotoxicity, toxicology, environment fate, and residue chemistry. In response to this DCI, the
registrants canceled all remaining food uses in 1992. Currently, the only two remaining products
containing MITC are for use on wood pilings, utility poles, and timbers for control of wood rot
and decay due to fungal activity. Both products are classified as restricted use.
III. Metam-sodium and Metam-potassium Risk Assessments
A. General Overview of Soil Fumigants
Soil fumigants are pesticides that form gasses when applied to soil. Once in the soil, the
fumigants work by controlling pests that can disrupt plant growth and crop production. Soil
fumigants play a very important role in agriculture, but they also have the potential to pose risk
concerns to people involved in application of the chemicals (handlers), workers who re-enter
fumigated fields (workers), and people who may be near the treated area (bystanders).
1. Human Health Risk
The main risk of concern for handlers, workers, and bystanders associated with the soil
uses of metam-sodium and metam-potassium is from acute inhalation exposure as a result of
fumigant off-gassing. Metam-sodium and metam-potassium handlers also are at risk from direct
fumigant exposure during applications. The term handler refers to persons involved in the
application. For soil applications, handlers also include persons involved in perforating and
removing of tarps. The term worker in this document refers to persons performing non-handler
tasks within the application block after the fumigation process has been completed, such as
planting. The term bystander refers to any person who lives or works in the vicinity of a
fumigation site.
In addition to the soil use of metam-sodium and metam-potassium, there are other uses
that the Agency has assessed and included in this RED: (1) metam-sodium as a root control agent
in sewers and drains and as an antimicrobial agent to treat wooden poles, timbers, sewage sludge,
and animal waste; (2) metam-potassium as an antimicrobial agent for treatment of pulp and
paper, leather tanning drum, recirculating cooling water systems, and industrial water
purification systems; and (3) MITC as an antimicrobial agent to treat wood poles and pilings.
When metam-sodium and metam-potassium are applied and mixed with moist soil or
water, they are quickly broken down into several strong irritant products. One of these products
19
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is MITC, which accounts for most of the fumigant activity. Based on monitoring data, it is clear
that bystander exposures to concentrations of MITC in the air after a metam-sodium/potassium
application are possible. Therefore, the focus in assessing inhalation bystander and occupational
exposures resulting from metam-sodium/potassium applications is on concentrations of MITC.
Estimating exposure to fumigants is different from non-fumigant pesticides due to
fumigants' volatility and thus, increased ability to move off site during and after application.
For example, pesticide spray drift is the physical movement of pesticide particulate or droplets
from the target site during the application and soon thereafter. In the case of soil fumigants, the
pesticide moves as a gas (not as particulate or droplets), and movement off site can occur for an
extended period after application. Importantly, fumigants have a well-documented history of
causing large-scale human exposure incidents up to several thousand feet from treated fields.
Assessing fumigant exposure takes into account the size of the fumigated field, the amount of
fumigant applied, and the rate at which the fumigant escapes from the treated field.
The term "flux rate" or "emission rate" defines the rate at which a fumigant off-gasses
from a treated field. Many factors influence the rate of emissions from treated fields after the
application of soil fumigants. Factors such as the application method, soil moisture, soil
temperature, organic matter levels, water treatments, the use of tarps, biological activity in the
soil, soil texture, weather conditions, soil compaction, and others influence the amount of
fumigant that comes off the field and is available to move off site to areas where bystanders may
be located.
The human health risk assessment indicates that acute inhalation exposures to MITC of
22 ppb or greater for a 1 to 8 hour time period for non-occupational (residential) bystanders and
occupational handlers could potentially pose risks of concern. The 22 ppb concentration is based
on a reversible endpoint from a human eye irritation and odor threshold study for acute
exposures to MITC. The lowest observable adverse effect level (LOAEL) was 800 ppb, and the
human concentration (HC) based on the No Observable Adverse Effect Level (NOAEL) from
this study is 220 ppb. The NOAEL of 220 ppb being used by EPA is similar to a benchmark
concentration level of 200 ppb submitted by the group Toxicology Excellence in Risk
Assessment (TERA) on behalf of the metam-sodium and metam-potassium registrants. The
benchmark concentration analysis thus supports the Agency's toxicity endpoint. Since the study
is a human exposure study for acute eye exposure to MITC, the standard 10X for animal to
human extrapolation is not needed. However, a 10X human variability uncertainty factor for
MITC was included, which when applied to the HC, results in the target concentration for acute
inhalation exposures of 22 ppb.
California Pesticide Illness Surveillance Program data from 1992-2003 confirm that eye
effects from MITC exposure as seen in this human study provide a sensitive endpoint for
regulating acute inhalation exposures. In many incident cases, people complain of eye effects.
However, many reported cases also report systemic or respiratory effects, and a few have effects
without eye irritation. Compared to eye irritation, the systemic and respiratory effects are more
adverse in nature. Unfortunately, the available toxicity data in animals or humans do not allow a
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quantitative comparison of the dose response curves of the eye, systemic, and respiratory effects
to determine the exact doses at which those effects occur. However, the Agency believes eye
irritation provides a surrogate for other toxic effects and thus makes this the appropriate endpoint
to regulate. To ensure that this endpoint is protective of any effects from repeated and longer-
term exposures, EPA is requiring data to evaluate developmental, reproductive, chronic, and
cancer hazards and has encouraged the registrants to pursue additional studies to characterize the
dose response curves of different target organs.
The Agency has not revised the 10X human variability uncertainty factor for MITC and
the MITC-generating compounds. Agency scientists have carefully reviewed comments
provided by the Metam Alliance and TERA that claim a mode of action (MOA) evaluation for
MITC and the relative sensitivities of the eyes and lungs to MITC, support an uncertainty factor
less than 10X. Upon request by the Metam Alliance, Agency scientists have evaluated the
registrant's scientific position [see www.regulations.gov, docket number: EPA-HQ-OPP-2005-
0125]. While Agency scientists acknowledge that data are available to formulate a hypothesis
for a MO A, currently available data are insufficient to support the key events of the proposed
MOA and also to refute other scientifically plausible hypotheses (a step critical in a MOA
framework analysis). Moreover, there remains uncertainty with respect to the dose response
relationship for sensitive measures of respiratory effects. Thus, given gaps in the existing data
for MITC, the Agency is unable to determine, according to existing guidance, that the
uncertainty factor can be reduced. If, in the future, additional data are provided, the Agency will
re-evaluate the scientific basis for MITC's human variability uncertainty factor.
In assessing risks from metam-sodium and metam-potassium, the Agency considered
multiple lines of evidence, using the best available information from monitoring studies,
modeling tools, and incident data.
• Monitoring: For the human health risk assessments completed for metam-sodium and
metam-potassium and the other soil fumigants within the group, several field-scale
monitoring studies were considered, as well as monitoring of workers and handlers
involved in various tasks. These studies quantify metam-sodium and metam-potassium
concentrations in and around fields at various times and distances during and after
applications. Many of these data indicate that there can be risks of concern associated
with metam-sodium and metam-potassium use at a broad range of distances from treated
fields. However, these data are limited in their utility because they provide results only
for the specific conditions under which the study was conducted.
• Modeling: Models enable the use of data from monitoring studies to estimate
concentrations and potential risks under a wide range of conditions and use patterns.
EPA used the Version 2.1.4 of the Probabilistic Exposure and Risk model for Fumigants
(also called the PERFUM model), to evaluate potential risks at distances around treated
fields. PERFUM incorporates actual weather data and flux distribution estimates, then
accounts for changes and altering conditions. Analyses based on a variety of model
outputs were used to compare the potential risks at a range of distances. The PERFUM
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model and users manual are public domain and can be downloaded at
http ://www. exponent, com/perfum/.
• Bystander, Handler, and Worker Incident Reports: Exposure incidents for the soil
fumigants generally occur at a low frequency relative to the total number of fumigant
applications performed annually. However, when fumigant incidents occur, there are
often many people involved. Incidents involving workers tend to occur more often than
incidents with bystanders.
Reconstructing incidents to examine the exact factors that led to the incident can be
difficult, especially when bystanders are involved, since all the factors that contributed to the
incident may not have been documented. Some of the factors that have been linked to incidents
in the past have included equipment failure, handler accidents, applicator failure to adhere to
label recommendations and/or requirements, and temperature inversions. Incidents have
occurred to bystanders close to fields and up to two miles away from the fumigated field.
Based on these lines of evidence, and as described in more detail in the risk assessments,
EPA has determined that metam-sodium and metam-potassium risks to handlers, workers, and
bystanders are of concern given current labels and use practices. The human health risk
assessments indicate that inhalation exposures to bystanders who live and work near agricultural
fields and greenhouses where metam-sodium and metam-potassium soil fumigations occur have
the potential to exceed the Agency's level of concern without additional mitigation measures.
There are also risks of concern for occupational handlers involved in metam-sodium and metam-
potassium applications and tarp perforation/removal activities and for workers who may re-enter
the treated area shortly after fumigation or tarp perforation has been completed.
For more information about the specific information in the Agency's human health risk
analyses, the documents listed below are relevant and available in the metam-potassium docket
(EPA-HQ-OPP-2005-0125) at www.regulations.gov.
• Methyl Bromide, 1,3-Dichloropropene, Chloropicrin, Dazomet, Metam
Sodium/Potassium, MITC: Health Effects Division (HED) Component of Agency
Response To Comments On 2008 Reregi strati on Eligibility Documents. May 14,
2009.
• EPA-HQ-OPP-2005-0125-0269, Metam-sodium: Final Revised Chapter of the
Registration Eligibility Decision Document (RED); DP Barcode: D293354, Metam-
sodium PC Code: 039003, Metam-potassium PC Code: 039002, MITC PC Code
068103. June 24, 2008.
• EPA-HQ-OPP-2005-0125-0261, Mode of Action, Eye Irritation, and the Intra-
Species Factor: Comparison of Chloropicrin and MITC. (Lowit, A. and Reaves, E.).
May 27, 2008.
• EPA-HQ-OPP-2005-0125-0074, Review of Fumigants Group Incident Reports
• EPA-HQ-OPP-2005-0125-0075, Summary Fumigants Group Incident Reports
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• EPA-HQ-OPP-2005-0125-0103, Summary of Fumigants Group Incident and Other
Data
• EPA-HQ-OPP-2005-0125-0005, Metam-sodium Bystander Risk Assessment Report
• EPA-HQ-OPP-2004-0159-0106, Revised Metam-sodium: Occupational and
Residential Exposure Assessment for the Reregi strati on Eligibility Decision
Document. (PC Codes 039003 and 068103; DP Barcode D293328)
2. Environmental Fate, Ecological Effects and Risks
The Agency's environmental fate and ecological effects risk assessments indicate that
there may be some concerns for non-target organisms that may be exposed to metam-sodium and
potassium.
Metam-sodium and potassium degrade rapidly in soil to generate MITC, the volatile
biocidal active product. Once MITC volatilizes into the atmosphere, it degrades rapidly due to
direct photolysis. The primary concern for metam-sodium is the potential for acute exposure of
terrestrial and aquatic organisms to MITC. Exposure to terrestrial organism such as birds and
mammals to MITC would likely occur by the inhalation route. Potential exposure to aquatic
organisms may occur from surface runoff/leaching and drift (wind) of MITC.
Hazard
Metam-sodium is considered moderately toxic on an acute oral basis to birds (LD50 = 211
mg/kg). MITC is considered highly toxic on an acute oral basis to mammals (LD50 = 55 mg/kg),
and moderately toxic via the inhalation route. Acute inhalation toxicity data with MITC are not
available for birds.
MITC is considered very highly toxic to both fish (lowest LCso = 51.2 ppb) and aquatic
invertebrates (lowest LCso = 55 ppb).
Exposure
Terrestrial
Exposure of MITC to terrestrial animals was evaluated using the Industrial Source
Complex Short Term (ISCST3) model together with information about MITC emissions from a
treated field, taking into account the range of MITC concentrations which might be found under
different conditions of application rate, weather, source size and shape (e.g., field size in acres)
and distance from the treated field.
Aquatic
For MITC exposure to fish and aquatic invertebrates, EPA considers surface water only,
since most aquatic organisms are not found in ground water. The aquatic exposure assessment
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for MITC relied on Tier II aquatic models. The Pesticide Root Zone Model (PRZM version
3.1.2 beta) simulates fate and transport on the agricultural field, while the water body is
simulated with Exposure Analysis Modeling System (EXAMS version 2.98.04). Simulations are
run for multiple (usually 30) years and the reported estimated environmental concentrations
(EECs) represent the values that are expected once every ten years based on the thirty years of
daily values generated during the simulation for selected scenarios.
PRZM/EXAMS simulates a 10 hectare (ha) field immediately adjacent to a 1 ha pond, 2
meters deep with no outlet. The location of the field is specific to the crop being simulated using
site-specific information on the soils, weather, cropping, and management factors associated with
the scenario. The crop/location scenario in a specific state is intended to represent a high-end
vulnerable site on which the crop is normally grown. Based on historical rainfall patterns, the
pond receives multiple runoff events during the years simulated. PRZM has limited capabilities
in capturing the amount of a volatile chemical in air, water, and sediment. The estimated
concentrations of chemicals like MITC in surface water bodies may be upper bound.
To simulate field application of metam-sodium, multiple scenarios were selected
representing metam usage areas based on geography and weather. PRZM and EXAMS models
are relevant scenarios were used to estimate MITC EECs in surface water based on label
information for metam-sodium application to onions, turf, tomatoes, and potatoes at the highest
application rate.
Risk
Terrestrial Risk
A refined analysis using mammal inhalation data and both monitoring and modeling data
for air concentrations of MITC do not indicate an acute risk of concern for wild mammals.
Avian acute toxicity data via the inhalation route are needed to evaluate risk to birds.
Risk to Plants
There is some uncertainty associated with risk of MITC to non-target plants, given the
data gaps for guideline terrestrial plant toxicity data and an incomplete aquatic plant toxicity
database. However based on the labeled phytotoxicity of MITC and some incidents, it is
expected that at lease some non-target terrestrial plants off site may be at risk from off-gassed
MITC.
Aquatic Risk
Acute aquatic levels of concern (LOCs) are slightly exceeded for MITC for both aquatic
invertebrates [risk quotients (RQs) range from 0.15 to 0.64] and fish (RQs range 0.16 to 0.69).
However, chronic exposure to MITC is expected to be low because of its high potential to
volatilize from surface water bodies.
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Due to the current data gaps for MITC, the Agency is requiring additional eco-toxicity
studies for both terrestrial and aquatic organisms.
For more information on the Agency's environmental fate and ecological effects risk
analysis, refer to the document listed below:
• EPA-HQ-OPP-2004-0159-0118, Revised Environmental Fate and Ecological Effects
Risk Assessment for Metam-sodium and Metam-potassium. (PC Codes 039003 and
039002; DP Barcode D293339).
3. Benefits
Soil fumigation can provide benefits to both food consumers and growers. For
consumers it means more fresh fruits and vegetables can be cheaply produced domestically year-
round because severe pest problems can be efficiently controlled. Benefits to crop production
from metam-sodium/potassium use accrue either from superior pest control (e.g., tomatoes) or
lower production costs (e.g., carrots, onions, peanuts), or both (e.g., cucurbits, peppers, potatoes),
as compared to the next best alternative. Commercially feasible alternatives frequently include
other soil fumigants such as chloropicrin and 1,3-dichloropropene (or mixtures of both).
However, feasibility of using 1,3-dichloropropene as an alternative is limited in California, a
major usage region for metam-sodium/potassium, due to local township caps on annual amounts
permitted for use across all crops. Alternatives that may become commercially viable in the
longer term include dimethyl disulfide (DMDS) and iodomethane, both in combination with
chloropicrin. However, in the context of high metam-use sites, these materials are relevant only
to cucurbits, peppers, and tomatoes, since these are the only metam-using crops for which
registration of either chemical has been approved or is currently under consideration.
The table below (Table 4) summarizes some aspects of the importance of metam-sodium
and metam-potassium to crop production in all crops for which benefits assessments were
conducted by the Agency and these have not changed from the assessments included as part of
the July 2008 RED. For further details, the reader is referred to the impact assessments, carried
out by the Biological and Economic Assessment Division (BEAD), which are available in the
metam-sodium and metam-potassium docket (EPA-HQ-OPP-2005-0125) at
www.regulations.gov.
The economic benefits provided by metam-sodium and metam-potassium use in many of
the crops are estimated to be substantial. For example, in potatoes, without metam, growers
would likely switch to fumigation with 1,3-dichloropropene and chloropicrin, which is less
effective at controlling key soil pests and more costly. BEAD estimates that net operating
revenue, the difference between gross revenue and operating costs, would drop about 20% in
California and by about 85% in the Pacific Northwest. Net operating revenue is a rough measure
of grower income; it does not account for fixed costs of production. The annual regional
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economic value of metam-sodium and metam-potassium fumigation is estimated to be about $8
million per year in California and about $48 million per year in the Pacific Northwest.
Taken together, benefits analyses indicate that metam-sodium and metam-potassium use
is generally important in a variety of crops, and that if these fumigants could not be used, there
would likely be significant negative economic impacts.
Table 4. Summary of benefits to crop production from metam-sodium & metam-
potassium
Crop
Carrots
Cucurbits
Eggplant
Grapes -
vineyard replant
Nursery stock
(fruit seedlings
and roses)
Onions
Likely Alternatives
to Metam
1,3-D (with and
without
chloropicrin), plus
various herbicides
and fungicides to a
much lower extent.
1,3-D (with and
without
chloropicrin), plus
various herbicides
and fungicides
1,3-D (with and
without chloropicrin)
1,3-D (with and
without
chloropicrin),
1,3-D (with and
without
chloropicrin), plus
various herbicides
and fungicides
Predicted impacts of loss of Metam-sodium/Metam-potassium use
BEAD estimates the benefit of metam-sodium in California carrot
production to be about $3.5 million annually resulting from reduced
production costs compared to fumigation with 1,3-dichloropropene and
applications of other herbicides and fungicides. However, 1,3-
dichloropropene is subject to regulatory restrictions in California that may
limit its availability for use by carrot growers. If 1,3-dichloropropene were
not available to California growers, the benefits of metam-sodium could be
as much as $140 million. In California, net operating revenue (NOR) could
drop by 17 % if the likely alternative replaces metam-sodium. In
Washington, the drop in NOR is estimated at 26%.
Use of metam-sodium to control fungi and nematodes leads to improved
yields over fumigation with 1,3-dichloropropene and chloropicrin and
substantially reduces production costs, which makes cucurbit production
viable in infested areas. The total benefit of fumigating with metam-
sodium is about $100 million annually in gross production. NOR for
California growers drops by as much as 177% if metam is replaced with
the likely alternatives.
The benefits of metam-sodium include higher yields and lower costs
compared to fumigation with 1,3-dichloropropene and chloropicrin.
Benefits range from $290-l,080/acre. The total contribution of metam-
sodium to California eggplant production is between $72,500 and $270,000
annually.
Metam-sodium appears to be the preferred fumigant for vineyards in
Washington and Oregon, saving growers $25-50/acre over fumigation with
1,3-dichloropropene and chloropicrin. For the region, savings range from
$16,500-33,000 annually. Metam-sodium may also benefit producers
through improved yields over 1,3-dichloropropene alone.
Metam-sodium is used in nursery stock production throughout the U.S.,
however, few data are available to permit reliable estimates of area treated
or quantity of fumigant used. Soil fumigation in nursery production
controls diseases, nematodes and weeds and results in higher yields, higher
quality plant production, and lower costs of production. Because of the
great diversity of plants and production conditions and a general lack of
data, BEAD has not been able to quantify the benefits, but they extend
beyond producers to include consumers of nursery products and multiply
considerably throughout the various production chains.
Metam-sodium is about $34/acre less expensive than 1,3-dichloropropene
and chloropicrin in the production of storage onions in Washington and
Oregon, providing costs savings for the region ranging from $393,000 to
$537,000 annually.
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Crop Likely Alternatives
to Metam
Ornamentals Methyl bromide +
(floriculture chloropicrin, 1,3-D
only) (with and without
chloropicrin), plus
various herbicides
and fungicides
Peanuts 1,3-D (with and
without
chloropicrin),
aldicarb
Peppers 1,3-D (with and
without
chloropicrin), plus
various herbicides
and fungicides
Pome fruit 1,3-D (with and
(apples and without
pears) - orchard chloropicrin),
replant
Potatoes
Stone fruit
(apricot, cherry,
nectarine,
peach, plum
and prune)
Sweet potatoes
Tomatoes
1,3-D (+
chloropicrin).
Approx. 13 % yield
loss expected with
1,3-D+Chloropricrin
his alternative
1,3-D (with and
without
chloropicrin),
probably to a lesser
extent methyl
bromide +
chloropicrin
1,3-D (with and
without
chloropicrin), plus
various herbicides
and fungicides
1,3-D (with and
without
chloropicrin), plus
various herbicides
and fungicides;
methyl bromide +
chloropicrin (fresh
tomatoes only)
Predicted impacts of loss of Metam-sodium/Metam-potassium use
There is ample evidence of that fumigant use increases yield and quality
and lowers production costs. Variations in pests and conditions suggest that
yield and quality differences would be significant and that metam-sodium
plays a critical role. This is especially significant for the propagative sector
because changes in the supply of seedling stock would result in magnified
changes to future supplies of mature plants and their products.
The benefits of metam-sodium in peanut production are largely seen in the
North Carolina and Virginia areas. NOR for these growers drops by 7% if
l,3D+Chloropicrin replaces metam; NOR drops by about 60% if aldicarb
is the replacement.
Metam-Sodium, and to a lesser extent metam-potassium, improves yields
and saves on production costs compared to fumigation with 1,3-
dichloropropene and chloropicrin. Use of metam-sodium makes pepper
production viable on much of the 1,500 acres in pepper production in
California. Total benefits range from $0.5-33.1 million annually. NOR for
California growers drops by 15 to 51% if metam is replaced with the likely
alternatives.
Orchards are fumigated at replanting to decrease mortality of young trees,
improve growth and speed maturation, and increase yields throughout the
lifespan of orchards. While 1,3-dichloropropene and chloropicrin are used
more often, on appropriate soils, metam-sodium is often less expensive. In
the absence of chloropicrin, metam-sodium would result in improved
yields, valued at $92.8 million/year, overuse of 1,3-dichloropropene alone.
Some portion of the estimated benefits is passed along to consumers.
The benefits of metam-sodium include yield increases and lower
production costs. Overall, the annual benefits of metam-sodium are
estimated to be about $800 per acre in California, and about $250 per acre
in the PNW, which translates to benefits of about $8 million per year in
California, and about $48 million per year in the Pacific Northwest. At the
farm level, in California, NOR would drop by 20% and in the PNW, by
85% if metam is replaced by the likely alternatives.
As with pome fruit, orchards are fumigated prior to replanting to better
establish new trees, increase survival rates, improve growth and enhance
maturity, and increase yields throughout the lifespan of the orchard. On
appropriate soils, metam-sodium provides cost savings of about $60/acre
over 1,3-dichloropropene and chloropicrin.
Without metam-sodium, production of sweet potato would not be viable on
nearly 10% of California fields. The benefits of metam-sodium amount to
about $5.9 million in sweet potato production annually
Metam-sodium provides more complete control of pests than does 1,3-
dichloropropene and chloropicrin, which results in improved yields and
increased revenue of nearly $130/acre. This represents an annual value for
metam-sodium of about $7.3 million in California. Major use is in
processed tomato production in California. NOR for these growers drops
by about 13% if likely alternatives replace metam-sodium.
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Note: As part of the response to public comments received on the REDs, the Agency reviewed
the need for metam registration in the context of certain specialized situations (such as cover
crops), and for specific minor crops (such as seed crops) and concluded that benefits of metam
use there were important enough to warrant re-registration. This review is available in the BEAD
memo titled "Response to comments on use site restrictions included in the Reregi strati on
Eligibility Decision (RED) for Metam-Sodium and Metam-Potassium (DP # 363544)". This
topic is also discussed earlier in this document in the section titled "Rate reduction and Use
Sites".
There are a number of benefits assessments that have been completed by the Agency to
estimate the value of these chemicals to various industries, which are listed below.
• EPA-HQ-OPP-2005-0123-0321, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Metam-Sodium, and Methyl Bromide in Eggplant Production
• EPA-HQ-OPP-2005-0123-0322, Assessment of the Benefits Soil Fumigants (Methyl
Bromide, Chloropicrin, Metam-Sodium, Dazomet) Used by Forest Tree Seedling
Nurseries
• EPA-HQ-OPP-2005-0123-0323, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin, Dazomet, Metam Potassium and Metam Sodium for Use
in Raspberry Nurseries, Fruit and Nut Deciduous Tree Nurseries, and Rose Bush
Nurseries in California
• EPA-HQ-OPP-2005-0123-0324, Assessment of the Benefits of Soil Fumigation with
Chloropicrin and Metam-sodium In Onion Production
• EPA-HQ-OPP-2005-0123-0325, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin and Metam-sodium In Grape Production
• EPA-HQ-OPP-2005-0123-0326, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin and Metam-sodium In Tree Nut Production
• EPA-HQ-OPP-2005-0123-0327, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, and Methyl Bromide In Pome Fruit Production
• EPA-HQ-OPP-2005-0123-0328, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin, and Metam Sodium In Stone Fruit Production
• EPA-HQ-OPP-2005-0123-0329, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam-Sodium in Bell Pepper Production
• EPA-HQ-OPP-2005-0123-0330, Assessment of the Benefits of Soil Fumigation with
Metam-sodium in Potato Production
• EPA-HQ-OPP-2005-0123-0331, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam-sodium In Strawberry Production
• EPA-HQ-OPP-2005-0123-0332, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, Metam-sodium, and Dazomet In Strawberry Nursery
Runner Production
• EPA-HQ-OPP-2005-0123-0333, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide and Metam-sodium In Sweet Potato Production
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• EPA-HQ-OPP-2005-0123-0334, Assessment of the Benefits of Soil Fumigation with
Chloropicrin In Tobacco Production
• EPA-HQ-OPP-2005-0123-0335, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam-sodium in Tomato Production
• EPA-HQ-OPP-2005-0123-0336, Assessment of the Benefits of Soil Fumigation with
Metam Sodium in Carrot Production
• EPA-HQ-OPP-2005-0123-0337, Assessment of the Benefits of Soil Fumigation with
Metam Sodium in Peanut Production
• EPA-HQ-OPP-2005-0123-0338, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, Metam Sodium and Dazomet in Ornamental Production
• EPA-HQ-OPP-2005-0123-0339, Summary of the Benefits of Soil Fumigation with
Methyl Bromide in Crop Production
• EPA-HQ-OPP-2005-0123-0340, BEAD'S Planned Impact Assessments on Agricultural
Sites with Significant Use of Soil Fumigants
• Analysis of Soil Fumigant Risk Management Requirements using Geographic
Information Systems: Case Studies based on a Forest Seedling Nursery (DP# 363546)
4. 2008 RED Mitigation Impacts
Requirements in the July 2008 RED
The July 2008 RED acknowledged that even with the use of credits, there could be
significant economic impacts to some growers who may not be able to accommodate large
buffers based on their current application practices. However, the Agency believed that the
options provided in the scalable buffer approach in the fumigant REDs would allow growers the
flexibility to modify their practices to achieve smaller buffers; for example, by treating smaller
application blocks, switching to a lower emission application method, or by switching to an
alternative fumigant that would require smaller buffers. Therefore, the Agency concluded that
growers would be able to alter their fumigation applications, given the flexibility designed into
the system, in a manner that would enable growers to minimize the impact on production. The
Agency noted, however, that the buffers would significantly impact some growers by delays in
planting due to longer fumigation operations, additional planning, and more trips to the field for
planting and other operations if fumigating in smaller blocks resulted in staggered operations. It
was determined that some of these costs could be substantial in some production scenarios.
Comments on the July 2008 RED
The July 2008 RED requested commenters to submit a description of fumigation
practices and provide maps of their property illustrating locations of fields, offices, residences,
roads, and property lines so that the Agency could better understand the impacts of the mitigation
plan. In response, various stakeholders, including several forest seedling nursery operations,
submitted detailed information. From an analysis of the information submitted, including an
analysis of a nursery and options they would have for compliance, the Agency concludes that it
had overestimated the ease with which many growers and fumigators would be able to comply
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with the buffer requirements as presented in the July 2008 RED, and that potential impacts
would be much greater than previously anticipated for some types of production.
From the Agency's analysis, the primary driver of the impacts is the size of the buffer
zones, which will require many growers to divide their fields into smaller fumigation blocks to
achieve smaller buffer zone distances. Two other contributing factors are the prohibition on
buffers overlapping in space and time and the duration of the buffer zone. As discussed above,
the Agency has provided flexibility on overlapping buffers. Nevertheless, the analysis indicates
that the buffer system identified in the July 2008 RED can be less flexible than expected for
certain scenarios, and the associated field topography, field infrastructure, and need for a
consistent orientation in the application of a fumigant, constrain how a field may be divided.
Together, these requirements could result in the loss of part of a grower's field that can be
effectively fumigated. Further, there may be substantial delays in completing fumigations and
multiple trips to a field with fumigation equipment may often be necessary. Not only could there
be delays in production activities in these instances, but it may also be difficult to maintain
proper soil moisture over the period that multiple blocks would be fumigated. Soil moisture has
been identified as a critical element in controlling emissions. Some growers will face numerous
scheduling conflicts if they rely on commercial applicators, and the Agency estimates that
growers would be more likely to conduct their own fumigations. In addition, repeated trips to
the field to fumigate small blocks will increase costs, a further incentive for growers to conduct
their own fumigations.
The Agency does agree that compliance with buffer zone requirements as outlined in the
July 2008 RED would be a significant challenge for applicators and growers. However, field
flux studies, monitoring data, modeling analyses and information from incidents involving
fumigants continues to support a conclusion that metam-sodium and metam-potassium off-gasses
and moves away from treated fields at concentrations that have the potential to cause adverse
effects. Therefore, the Agency still believes that buffer zones that exclude bystanders are a
critical aspect of mitigating risks from metam-sodium and metam-potassium.
In addition to these impacts, if emergency preparedness and response requirements were
triggered due to proximity of neighbors, for example, the requirement in the July 2008 RED to
monitor the buffer zone for its duration was estimated to impose the highest direct costs. The
Agency estimates that the cost of sampling tubes alone could range from $1000 to over $3000
for a field or enterprise, not including the cost of labor. These costs would fall
disproportionately on growers with small acreage. As an alternative, growers could notify their
neighbors of their intent to fumigate. However, the Agency understands and appreciates the
many comments indicating that notification may not be an attractive option due to the potential
for neighbors to attempt to impede or block fumigant applications.
Finally, the Agency concludes that the development and implementation of workable
fumigation strategies, considering buffer and other requirements, will require substantial new
information and management skills on the part of growers and applicators. While the Agency's
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risk management approach provides flexibility to the grower, providing a reasonable period of
time for growers to adapt would reduce impacts.
Based on this new information and EPA's analyses, the Agency has identified
modifications to the mitigation which will maintain the important protections necessary for the
health and safety of workers and bystanders, but will increase the ability of fumigant users to
comply by reducing impacts associated with the mitigation. This includes allowing buffer zone
overlap and changes in monitoring requirements. In addition, due to new data that have been
submitted to the Agency, buffer zones distances for some scenarios have been refined. Although
many aspects of the RED mitigation will appear on labels in 2010, the Agency will not require
buffers until the 2011 growing season.
B. Overview of Sewer Use Risk
Because metam-sodium degrades rather quickly to MITC, short-term, intermediate-term,
and chronic inhalation exposures to metam-sodium by workers are expected to be negligible
when compared with MITC exposures. To address the short- and intermediate-term MITC
inhalation risks from MITC, in the July 2008 metam-sodium metam-potassium RED, the Agency
required that any person(s) engaged in any activities that are likely to involve direct contact with
metam-sodium (including, but not limited to, mixing, loading, and/or applying metam-sodium;
equipment calibration; cleaning and repair of application equipment; entering into treated areas;
sampling cleanup spills; and rinsate disposal) wear a half-face respirator with organic vapor
cartridge approved for MITC.
While there is insufficient toxicological data to characterize the inhalation cancer risk of
MITC, due to limitations in the rat and mouse MITC oral carcinogenicity studies, the Agency
anticipates that these new respiratory requirements will adequately address this risk. However,
the Agency is requiring additional study data for MITC.
The Agency revised the non-cancer, short- and intermediate-term occupational handler
dermal exposure assessments based on the additional usage and occupational exposure
information provided by the metam-sodium sewer use registrants. The results of the revised non-
cancer, short-term occupational handler dermal exposure assessments for the sewer use of
metam-sodium indicate that the MOEs for the dermal risk to handlers with engineering controls
(e.g., closed mixing and loading systems) were above or just below the target MOE of 100, and
the MOEs for the dermal risk to handlers with full dermal PPE (i.e., chemical resistant gloves
and double layer clothing) were above 49, even at the highest daily rates of amount of product
handled. In the case of the intermediate-term exposures with full dermal PPE, MOEs were below
the target MOE of 100, even with engineering controls. Although not all short- and
intermediate-term dermal exposure MOEs reached the target MOE of 100 with the required
dermal protection and engineering controls, the occupational handler dermal exposure
assessments are considered to be very conservative.
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EPA revised its occupational handler dermal cancer assessment for handlers engaged in
sewer applications of metam-sodium to control roots in sewer systems based on the additional
usage and occupational exposure information provided by the metam-sodium sewer use
registrants during the post-RED comment period. The results of the revised cancer occupational
handler dermal exposure assessment for the sewer use of metam-sodium indicate that cancer
risks for workers in full dermal PPE requirements (i.e., chemical resistant gloves and double
layer clothing) and/or those using engineering control technologies (i.e., closed mixing and
loading systems) are below the target cancer risk level of between IxlO"4 to IxlO"6 for exposed
handlers.
Based on the short- and intermediate-term dermal exposure risks to workers, coupled
with the worker risks associated with MITC inhalation exposures, the Agency is requiring that
any person(s) engaged in any activities that are likely to involve direct contact with metam-
sodium, including but not limited to mixing, loading, and/or applying metam-sodium; equipment
calibration; cleaning and repair of application equipment; entering into treated areas; sampling
cleanup of spills; and rinsate disposal, to wear double-layer clothing, chemical resistant gloves,
and a 90% protection factor respirator approved for MITC. To help mitigate these risks, the
Agency is also adding a requirement that closed engineering systems for all mixing and loading
activities be used.
For more information on the Agency's sewer use risk analysis, refer to the documents
listed below (all are available in the metam-sodium docket at www.regulations.gov):
• "Metam Sodium: Third Revision of the HED Human Health Risk Assessment;" May
2009; Charles Smith; Health Effects Division, U.S. EPA.
C. Overview of Antimicrobial Risk
Due to the short loading and/or application durations (i.e., minutes), handlers (i.e.,
mixers/loaders) are not expected to be exposed to the metam-sodium degradate, MITC.
However, the Agency has concerns for potential post-application inhalation exposures to MITC
after metam-sodium applications in the leather and/or sugar processing industries and also
workers in the vicinity of sewage sludge treatments. The Agency also has concerns for potential
post-application inhalation exposures to MITC for workers in the vicinity of metam-potassium
applications in the leather, pulp/paper, and sugar processing industries as well as in coatings and
metal working fluid manufacturing, oil-field operations, cooling water towers, and industrial
water purification facilities because MITC is a highly volatile organic chemical (vapor pressure
= 150 mmHg). Furthermore, since metam-sodium and metam-potassium convert to MITC in
aqueous media, the Agency also has concerns for the potential MITC inhalation exposures for
the machinist who works with metal-working fluids that were preserved with metam-potassium.
For more information on the Agency's antimicrobial use and industrial risk analysis, refer
to the documents listed below (all are available in the metam-sodium docket at
www.regulations.gov):
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EPA-HQ-OPP-2005-0125-0264, Revised Occupational and Residential/Bystander Assessment of
the Antimicrobial Use (Remedial Wood Treatment) of Chloropicrin for the Reregi strati on
Eligibility Decision (RED) Document (Phase 3 Comment Period). PC Code 081501, DP
Barcode D314399. February 14, 2008.
EPA-HQ-OPP-2005-0125-0076, Occupational and Residential/Bystander Assessment of the
Antimicrobial Use (Remedial Wood Treatment) of Methyl Isothiocyanate (MITC) for the
Reregi strati on Eligibility Decision (RED) Document
EPA-HQ-OPP-2005-0125-0077, Metam-potassium: Dietary Risk Assessment of Antimicrobial
Uses in Sugar Processing for the Reregistration Eligibility Decision Document
EPA-HQ-OPP-2005-0125-0078, Metam-potassium: Occupational and Residential Exposure
Assessment of Antimicrobial Uses for the Reregi strati on Eligibility Decision Document
EPA-HQ-OPP-2004-0159-0119, Metam-sodium: Revised Occupational and Residential
Exposure Assessment of Antimicrobial Uses for the Reregi strati on Eligibility Decision
Document. (PC Codes 039003 and 068103)
EPA-HQ-OPP-2004-0159-0006, Ecological Risk from Antimicrobial Uses of Metam-sodium to
be Considered in the RED
EPA-HQ-OPP-2004-0159-0017, Metam-sodium: Dietary Risk Assessment of Antimicrobial
Uses for the RED
IV. Risk Management and Reregistration Eligibility Decision
A. Determination of Reregistration Eligibility
Section 4(g)(2)(A) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA)
calls for the Agency to determine, after submission of relevant data concerning an active
ingredient, whether pesticides containing the active ingredient are eligible for reregi strati on. The
Agency has previously identified and required the submission of the generic (i.e., active
ingredient specific) data to support reregi strati on of products containing metam-sodium, metam-
potassium, and MITC.
In Phase 5, the Agency published a risk mitigation options paper.1 This document detailed
potential mitigation options and sought public comment on these options. The following is the
list of mitigation options discussed in the Agency's paper:
• Buffer zones;
• Sealing methods;
• Timing of applications;
• Application block size limitations;
• Respiratory protection;
• Tarp perforation/removal procedures;
1EPA-HQ-OPP-2005-0128-0031, Risk Mitigation Options to Address Bystander and Occupational Exposures from
Soil Fumigant Applications
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• Entry-restricted period;
• Application method/practice restrictions;
• Fumigant management plans (FMPs);
• FMP certification;
• Responsible parties;
• Record keeping/reporting/tracking;
• Restricted Use Pesticide Classification;
• Notification and posting;
• Good agricultural practices;
• Fumigant manuals; and
• Stewardship programs.
Based on a review of the metam-sodium, metam-potassium, and MITC
databases and public comments on the Agency's assessments for these active
ingredients, the Agency has sufficient information on the human health and ecological
effects of metam-sodium, metam-potassium, and MITC to make decisions as part of
the reregi strati on process under FIFRA. Further, based on the volatility of metam-
sodium, metam-potassium, and MITC and metabolism studies in plants, EPA has
concluded that there is a reasonable expectation that no residue on food or feed items
will occur with the use of these fumigants. Therefore, no tolerances have been
established.
As a result of this review, the Agency has determined that certain uses of (1) metam-
sodium (including use as a pre-plant soil fumigant in certain crops, as a root control agent in
sewers and drains, and as an antimicrobial agent to treat wood poles and timbers and sewage
sludge and animal waste); (2) metam-potassium (including use as a pre-plant soil fumigant in
certain crops and as an antimicrobial agent for treatment of pulp and paper, tanning drum leather
applications, recirculating cooling water systems, and industrial water purification systems); and
(3) MITC (for use as an antimicrobial agent to treat wood poles and pilings) are eligible for
reregi strati on, provided that the risk mitigation measures outlined in this document are adopted,
label amendments are made to reflect these measures (as outlines in Section V), and data are
developed to assess intermediate- and long-term risk to bystanders. Appendix A summarizes the
uses of metam-sodium, metam-potassium, and MITC that are eligible for reregi strati on.
The Agency's decision takes into account the best available information on the potential
risks and benefits of metam use. In reaching its reregi strati on decision and developing the
metam mitigation proposal, EPA considered a range of factors, including: characteristics of
bystander and other populations exposed to metam; hazard characteristics of metam-sodium,
metam-potassium, and MITC; available information on levels of exposure, feasibility, cost, and
effectiveness of various risk mitigation options; incident information; public comments; potential
impacts of mitigation on growers ability to produce crops; availability of efficacious alternatives;
comparative risks of alternative control methods; and the uncertainties and assumptions
underlying the risk and benefit assessments.
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Some uncertainty remains associated with intermediate- and long-term exposure and risk
to bystanders. To address these uncertainties, EPA is requiring additional data related to both
toxicity and exposure. Notwithstanding these uncertainties, the Agency has decided to proceed
with its reregi strati on decision and implementation of mitigation at this time because mitigation
implemented to address acute bystander risk will also serve to address intermediate- and long-
term bystander risk.
A substantial amount of research is currently underway or is expected to begin in the near
term to (1) address current data gaps, and (2) refine understanding of factors that affect fumigant
emissions. Additionally, a number of new methods and technologies for fumigation are
emerging. To ensure that data are developed and reviewed expeditiously, EPA plans to move the
soil fumigants forward in registration review, from 2017 to 2013, which will allow EPA to
consider new data and information relatively soon, determine whether the mitigation included in
this decision is effectively addressing the risks as EPA believes it will, and to include other soil
fumigants which are not part of the current review.
Voluntary Cancellation of Antimicrobial Uses
On May 15, 2008, the Agency received letters voluntarily cancelling several
antimicrobial uses for metam-sodium and metam-potassium. The antimicrobial uses of metam-
sodium that were cancelled included: (1) treatment of process waters during the production of
sugar (i.e., raw cane and beet sugars) and (2) treatment of brine-cured hides and skins (i.e.,
leather) during processing, and (3) treatment of sewage sludge and animal waste. The
antimicrobial uses of metam-potassium that were cancelled included: (1) the sugar beet and
sugar cane use; (2) all leather uses, with the exception of the tanning drum leather use; (3) all
paint uses (including the preservation of protective colloids and emulsion resins); (4) all water-
based drilling, completion, and packer fluid uses; (5) all petroleum secondary recovery operation
uses; (6) all once-through cooling water applications, and (7) all cutting fluids (metalworking
fluids) uses. As a result of these cancellations, these uses have not been evaluated in the RED.
The Agency has determined that the remaining registered antimicrobial uses for metam-
sodium (i.e., remedial treatment of wooden poles and timbers and treatment of sewage sludge
and animal waste), metam-potassium (i.e., use in tanning drum leather, pulp and paper,
recirculating cooling water systems, and industrial water purification systems), and MITC (i.e.,
remedial treatment of wooden poles and timbers) will not pose unreasonable risks or adverse
effects to humans or the environment, provided that the risk mitigation measures and label
changes outlined in this RED are implemented and, therefore, products containing metam-
sodium, metam-potassium, and MITC for these uses are eligible for reregi strati on.
Based on its evaluation of metam-sodium, metam-potassium, and MITC, the Agency has
determined that products containing these chemicals, unless labeled and used as specified in this
document, would present risks inconsistent with FIFRA. Accordingly, should a registrant fail to
implement any of the risk mitigation measures identified in this document, the Agency may take
regulatory action to address the risk concerns from the use of these chemicals. If all changes
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outlined in this document are incorporated into the product labels, then current risks for metam-
sodium, metam-potassium, and MITC will be adequately mitigated for the purposes of this
determination under FIFRA. Once a comprehensive endangered species assessment is
completed, further changes to these registrations may be necessary.
B. Public Comments and Responses
The Phase 3 public comment period on the preliminary risk assessments and related
documents lasted from July 13 through October 12, 2005. The Agency responses to Phase 3
public comments related to metam-sodium and metam-potassium soil uses, metam-sodium sewer
use, and antimicrobial uses for metam-sodium, metam-potassium, and MITC can be found in the
metam-sodium docket (EPA-HQ-OPP-2005-0125) at www.regulations.gov.
EPA revised its risk assessments and developed benefits and risk mitigation options
during Phase 4. The Phase 5 public comment period, for revised risk assessments, benefits
analysis, and risk management options, lasted from May 2 to November 3, 2007. The Agency
responses to Phase 5 public comments related to metam-sodium and metam-potassium soil uses,
metam-sodium sewer use, and antimicrobial uses for metam-sodium, metam-potassium, and
MITC can be found in the following documents, available in the metam-sodium docket (EPA-
HQ-OPP-2005-0125) at www.regulations.gov.
• The Health Effects Division's Response to Comments on EPA 's Phase 5
Reregistration Eligibility Decision Document for Dazomet. (Smith, C., Dated June
2008).
• Response to Phase 5 Public Comments on the Phase 4 Dazomet Environmental
Fate and Ecological Risk Assessment. (Khan, F., and Felkel, J., Dated April 2,
2008).
• Response to Phase 5 BEAD Related Public Comments Received on the
Reregistration of Chloropicrin, Dazomet, Metam Potassium, Metam Sodium, and
Methyl Bromide. (Donaldson, D. et al., Dated June 2008).
• Review of Stakeholder Submitted Impact Assessments of Proposed Fumigant
Buffers, Comments on Initial Buffer Zone Proposal, and Case Studies of the Impact
of a Flexible Buffer System for Managing By-Stander Risks ofFumigants. (Wyatt,
T., et al, Dated June 2008).
• Phase 6 Response to Substantive Public Comments on Antimicrobials Division's
Occupational and Residential Assessments for the Reregistration Eligibility
Decision (RED) Documents for the following chemicals: Methylisothiocyanate
(MITC), Metam Sodium, Dazomet, and Chloropicrin. (Walls, C., Dated February
14, 2008).
• SRRD 's Response to Phase 5 Public Comments for the Soil Fumigants. (Dated July
2008).
The Agency also opened a 60-day public comment period following the publication of the
Metam-Sodium and Metam-Potassium RED on July 16, 2008. The Agency received requests to
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extend the comment period, so in response to these requests, on August 29, 2008, EPA published
a notice in the Federal Register extending the comment period for an additional 45 days. The
comment period closed on October 30, 2008. The Agency has reviewed these public comments
as well as new scientific data and other information provided and determined that all measures
established in the July 2008 RED to reduce risks to bystanders and workers will still be required.
The Agency has determined that certain modifications in how and when some measures will be
implemented are appropriate. The following documents include EPA's responses to comments
on the July 2008 RED which may be found in the metam-sodium and metam-potassium docket:
• Further Response to Public Comments on the 7/9/08 Completed Dazomet RED.
(Dated March 3, 2009).
• Methyl Bromide, 1,3-Dichloropropene, Chloropicrin, Dazomet, Metam
Sodium/Potassium, MITC: Health Effects Division (HED) Component of Agency
Response To Comments On 2008 Reregistration Eligibility Documents (Dated May
14, 2009).
• Response to BEAD Related Public Comments Received on the Reregistration
Eligibility Decision for Chloropicrin, Dazomet, Metam Potassium, Metam Sodium,
and Methyl Bromide (DP# 363545; Dated May 14., 2009).
• Analysis of Soil Fumigant Risk Management Requirements using Geographic
Information Systems: Case Studies based on a Forest Seedling Nursery (DP#
363546; Dated May 13, 2009).
• SRRD's Response to Post-RED Comments for the Soil Fumigants (Dated May 20,
2009).
C. Regulatory Position
1. Regulatory Rationale
The Agency has determined that products containing metam-sodium, metam-potassium,
and MITC are eligible for reregi strati on provided the risk mitigation measures outlined in this
document are adopted and label amendments are made to reflect these measures. EPA has
determined that the modifications to the measures outlined in the July 2008 RED, described
herein, will achieve the same protection goals for persons potential exposted to metam-sodium
and metam-potassium but with a greater likelihood of compliance, fewer inpacts on the benefits
of metam use, and with less uncertainty regarding the protectiveness of the required measures.
The following is a description of the rationale for managing risks associated with the use of these
fumigants. Where labeling revisions are warranted, specific language is set forth in the label
table in Section V of this document.
a. Soil Fumigant Uses of Metam-sodium and Metam-potassium
i. Rate Reduction and Use Sites
While most current labels for metam-sodium and metam-potassium state that 320 Ib ai/A
is the maximum allowed rate, there are some labels which suggest that calculated rates may be
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higher than 320 Ib ai/A. To consistently clarify the maximum application rates for pre-plant soil
fumigation, label language will be required to specifically state 320 Ib ai/A as the upper limit for
all application methods. No other rate changes for soil fumigation uses are required in this
decision.
1. Use Sites Eligible for Reregistration
In the July 2008 Metam-Sodium and Metam-Potassium RED, the Agency determined the
following uses to be eligible for reregi strati on: asparagus (nursery production only), artichokes,
broccoli, brussels sprouts, cabbage, carrot, cauliflower, celery, cucurbits (cucumber, cantaloupe,
honeydew, pumpkin, squash, and watermelon), eggplant, forest seedlings, grape (vineyard
replant only), lettuce, mint, nursery stock (fruit seedlings and rose bushes only), oranges, onion,
pome fruit (apples and pears; orchard replant only), stone fruit (apricot, cherry, nectarine, peach,
plum and prune; orchard replant only), ornamentals (floriculture only), peanut, pepper, potato,
spinach, strawberries, sweet potato, tobacco, tomatoes, and turf (including golf courses).
This list of crops was based on one or more of the following criteria: (1) the crop showed
significant usage of metam-sodium and metam-potassium, as indicated by BEAD usage data,
and/or (2) stakeholders for the crop submitted compelling benefits information for metam-
sodium and metam-potassium use during the Phase 5 comment period, and/or (3) removal of
metam-sodium and metam-potassium use appeared likely to increase use of methyl bromide,
which is being phased out under the Montreal Protocol. "Significant usage" was defined as a
crop that has more than 5% crop treated annually or more than 1,000,000 Ib of metam sodium or
metam potassium applied annually.
All other pre-plant uses were to be deleted, unless additional information to support a
compelling case for the economic benefits of metam-sodium and metam-potassium was
provided. This decision was based on potentially high risk to bystanders from metam-sodium and
metam-potassium, coupled with a lack of indication of high economic benefits for crops not
included in the group described above.
During the post-RED comment period, the Agency received comments from various
stakeholders asking that the Agency consider the eligibility of additional use sites. Key
considerations identified during the post-RED comment period included:
• Crops that are typically included as part of a rotational schedule or cover crop regimen. The
Agency agrees that limiting the use metam-sodium and metam-potassium may have some
unintended consequences. These include preventing good soil erosion management (with
cover crops), and magnifying the negative economic impact on growers who have to alter
their crop rotation scheme unexpectedly due to, for example, changes in weather conditions
or economic considerations, such as contractual agreements with processors. As a result, the
following crops, which have been reported to be part of typical rotational schedules for
metam users, will be added as eligible use sites: alfalfa, barley, rye, sugar beets, corn, and
wheat. In addition, the Agency will add "cover crops," i.e., crops planted between periods of
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regular crop production to prevent soil erosion, control weeds, and improve soil quality that are
incorporated into the soil before the next crop is planted and may not be harvested for food or feed, to
the list of eligible use sites for metam-sodium and metam-potassium.
Use of metam-sodium and metam-potassium as a potential alternative to methyl bromide for
orchard replant of tree nuts, berry crops, ginger, and pineapple. The Agency analyzed the use
of soil fumigants for orchard replant of tree nut crops, berry crops (i.e., blueberry, blackberry,
raspberry, etc.), ginger, and pineapple and determined that restriction of these uses of metam-
sodium and metam-potassium are likely to lead to an increased reliance on methyl bromide.
As a result, orchard replant of tree nuts, berry crops, ginger, and pineapple have been added
as eligible use sites for metam-sodium and metam-potassium.
Metam-sodium and metam-potassium use on minor crops. The Agency received comments
from stakeholders asking that several minor uses (e.g., arugula, wild rocket, and parsley;
grapefruit) of metam-sodium and metam-potassium be considered eligible. While such minor
crop uses might not reach the threshold of "significant usage," in cases where the crops
mentioned were likely to be similar to others that were retained for reregi strati on, in terms of
the pest management needs and crop production benefits, the Agency made sure to evaluate
those uses for eligibility in the RED addendum. Specifically, the Agency is including several
of the EPA crop group listings as eligible use sites to provide growers additional flexibility
with regard to use site eligibility [for a description of these crop groups, see "Pesticide
Tolerances; Revision of Crop Groups, Final Rule, Federal Register Notice, May 17, 1995
(Volume 60, Number 95); http://www.epa.gov/fedrgstr/EPA-PEST/1995/Mav/Dav-17/pr-
266.html1. As an example, by including "EPA Crop Group 4, Leafy Vegetables" as an eligible
use site, arugula, wild rocket, parsley and a number of other potential minor uses, which are
similar to lettuce and spinach in terms of the pest management needs and crop production
benefits, become eligible use sites. Further, the Agency is adding "crops grown solely for
seed" to the list of eligible use sites, because information from growers and extension agents
indicates that, while a minor use, use of soil fumigants on seed crops is important for control
of weeds and disease.
California Department of Pesticide Regulation usage data. In responding to the post-RED
comments, the Agency examined the California Department of Pesticides (CDPR) pesticide
usage data for recent years (2003-2006), since the state generally is a significant user of
metam-sodium and metam-potassium products and is a major producer of a diverse array of
crops that may rely on soil fumigation, to ensure that it did not miss any important uses of
metam. Based on these data, it appears that there are few crops not already deemed eligible
for reregi strati on that do not meet the criterion of 5% or more of the crop acreage treated
annually. Only seven additional crops, including sweet basil, Chinese greens (often a
synonym for bok choy), celeriac (a member of the celery family), collard, dill, leeks, and
Swiss chard, were identified as having 5% or more of the crop treated in at least one year
during the time period studied. Based on this analysis, the Agency is adding these seven
additional to the list of eligible use sites for metam-sodium and metam-potassium.
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Based on the original criteria for determining eligible use sites (see above) as well as the
comments and additional information received during the post-RED comment period, the EPA
has determined that the following expanded list of metam-sodium and metam-potassium use sites
are eligible for reregi strati on. All other pre-plant uses are to be deleted, and product labels must
be amended to reflect use only on the crops specified as eligible for reregi strati on.
• Alfalfa,
• Asparagus (nursery production only),
• Artichokes,
• Barley,
• Basil,
• Beet,
• Berries, [includes all EPA Crop Group 13, Berries Group, i.e., blackberry (Rubus eubatus);
bingleberry; black satin berry; boysenberry; Cherokee blackberry; chesterberry; Cheyenne
blackberry; coryberry; darrowberry; dewberry; Dirksen thornless berry; Himalayaberry; hullberry;
lavacaberry; lowberry; lucretiaberry; mammoth blackberry; marionberry; nectarberry; olallieberry;
Oregon evergreen berry; phenomenalberry; rangeberry; ravenberry; rossberry; Shawnee blackberry;
youngberry, and varieties and/or hybrids of these; blueberry (Vaccinium spp.); currant (Ribes spp.);
elderberry (Sambucus spp.); gooseberry (Ribes spp.); huckleberry (Gaylussacia spp.); loganberry
(Rubus loganobaccus); raspberry-black and red (Rubus occidentalis, Rubus strigosus, Rubus idaeus)],
• Broccoli,
• Brussels sprouts,
• Cabbage,
• Carrot,
• Cauliflower,
• Celeriac,
• Chineese greens or bok choy,
• Cilantro,
• Citrus (orchard replant only), [includes all of EPA Crop Group 10, Citrus Fruits, i.e., calamondin
(Citrus mitis X Citrofortunella mitis); citrus citron (Citrus medico); citrus hybrids (Citrus spp.)
(includes: chironja, tangelo, tangor); grapefruit (Citrusparadisi); kumquat (Fortunella spp.); lemon
(Citrus jambhiri, Citrus limon); lime (Citrus aurantiifolia); mandarin (tangerine) (Citrus reticulata);
orange, sour (Citrus aurantium); orange, sweet (Citrus sinensis); pummelo (Citrus grandis, Citrus
maxima); satsuma mandarin (Citrus unshiu)},
• Collard,
• Corn,
• Cover crops (i.e., crops planted between periods of regular crop production to prevent soil erosion,
control weeds, and improve soil quality that are incorporated into the soil before the next crop is
planted and may not be harvested for food or feed),
• Crops grown solely for seed,
• Cucurbits [includes all of EPA Crop Group 9, Cucurbit Vegetables Group, i.e., chayote (fruit)
(Sechium edule); Chinese waxgourd (Chinese preserving melon) (Benincasa hispida); citron melon
(Citrullus lanatus var. citroides); cucumber (Cucumis sativus); gherkin (Cucumis anguria); gourd,
edible (Lagenaria spp.) [includes: hyotan, cucuzza (Luffa acutangula, L. cylindrical; includes
hechima, Chinese okm)];Momordica spp. (includes balsam apple, balsam pear, bitter melon, Chinese
cucumber); muskmelon [hybrids and/or cultivars of Cucumis melo (includes true cantaloupe,
cantaloupe, casaba, crenshaw melon, golden pershaw melon, honeydew melon, honey balls, mango
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melon, Persian melon, pineapple melon, Santa Claus melon, and snake melon)]; pumpkin (Cucurbita
spp.); squash, summer (Cucurbitapepo var. melopepo) (includes: crookneck squash, scallop squash,
straightneck squash, vegetable marrow, and zucchini); squash, winter (Cucurbita maxima; C.
moschata) (includes: butternut squash, calabaza, hubbard squash) and (C. mixta; C. pepo) (includes
acorn squash, spaghetti squash); and watermelon (includes hybrids and/or varieties ofCitrullus
lanatus)},
• Dill,
• Eggplant,
• Forest seedlings,
• Ginger,
• Grape (vineyard replant only),
• Kale,
• Kohlrabi,
• Leafy greens [includes all of EPA Crop Group 4, Leafy Vegetables (Except Brassica Vegetables), i.e.,
amaranth (leafy amaranth, Chinese spinach, tampala) (Amaranthus spp.); arugula (roquette) (Eruca
sativa); cardoon (Cynara cardunculus); celery (Apium graveolens var. dulce); celery, Chinese (Apium
graveolens var. secalinum); celtuce (Lactuca sativa var. angustana); chervil (Anthriscus cerefolium);
chrysanthemum, edible-leaved (Chrysanthemum coronarium var. coronarium); chrysanthemum;
garland (Chrysanthemum coronarium var. spatiosum); corn salad (Valerianella locusta); cress,
garden (Lepidium sativum); cress, upland (yellow rocket, winter cress) (Barbarea vulgaris);
dandelion (Taraxacum officinale); dock (sorrel) (Rumex spp.); endive (escarole) (Cichorium endivia);
fennel, Florence (fmochio) (Foeniculum vulgare Azoricum Group); lettuce, head and leaf (Lactuca
sativa); orach (Atriplex hortensis); parsley (Petroselinum crispum); purslane, garden (Portulaca
oleracea); purslane, winter (Montiaperfoliata); radicchio (red chicory) (Cichorium intybus); rhubarb
(Rheum rhabarbarum); spinach (Spinacia oleracea); spinach, New Zealand (Tetragonia
tetragonioides, T. expansa); spinach, vine (Malabar spinach, Indian spinach) (Basella alba); and
swiss chard (Beta vulgaris var. cicla)],
• Leek,
• Mint,
• Mustard,
• Nursery stock (fruit seedlings and rose bushes only),
• Onion,
• Ornamentals (floriculture only),
• Pome fruit (orchard replant only), [includes all of EPA Crop Group 11, Pome Fruits Group —
Commodities, i.e., apple (Mains domestica); crabapple (Mains spp.); loquat (Eriobotrya japonica);
mayhaw (Crataegus aestivalis, C. opaca, and C. rufiila); pear (Pyrus communis); pear, oriental
(Pyrus pyrifolia); and quince (Cydonia oblonga)},
• Peanut,
• Pepper,
• Potato,
• Radish,
• Rye,
• Sugar beet,
• Soybean,
• Stone fruit (orchard replant only), [includes all of EPA Crop Group 12, Stone Fruits Group—
Commodities, i.e., apricot (Prunus armeniaca); cherry, sweet (Prunus avium); cherry, tart (Prunus
cerasus); nectarine (Prunuspersica); peach (Prunuspersica); plum (Prunus domestica, Prunus spp.);
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plum, Chickasaw (Prunus angustifolia); plum, Damson (Prunus domestica spp. insititia); plum,
Japanese (Prunus salicina); plumcot (Prunus. armeniacaXP. domestica); prune (fresh) (Prunus
domestica, Prunus spp.}},
• Strawberries,
• Sugar beet,
• Sweet potato,
• Swiss Chard,
• Tobacco,
• Tomatoes,
• Tree nuts (orchard replant only), [includes all of EPA Crop Group 14, Tree Nuts Group (i.e., almond
(Prunus dulcis); beech nut (Fagus spp.); Brazil nut (Bertholletia excelsa); butternut (Juglans
cinered); cashew (Anacardium occidentale); chestnut (Castanea spp.); chinquapin (Castanea
pumila); filbert (hazelnut) (Corylus spp.); hickory nut (Carya spp.); macadamianut (bush nut)
(Macadamia spp.); pecan (Carya illinoensis); and walnut, black and English (Persian) (Juglans spp.)
as well as pistachio],
• Turnip,
• Turf (including golf courses), and
• Wheat
ii. Human Health Risk Management
For details on the metam-sodium and metam-potassium human health risk assessment,
please refer to the human health risk assessments and addenda. These documents are also
available in the public docket EPA-HQ-OPP-2005-0125, located on-line in the Federal Docket
Management System (FDMS) at www.regulations.gov.
Dietary Risk
Based on the currently registered use patterns for metam-sodium and metam-potassium,
dietary exposure, including exposure from drinking water, is not expected and no dietary risk
mitigation is warranted for metam-sodium and metam-potassium at this time.
Bystanders, Workers, and Handlers
The human health risk assessments indicate that inhalation exposures to bystanders,
handlers, and workers who live and work near agricultural fields and greenhouses where metam-
sodium/potassium fumigations occur have the potential to exceed the Agency's level of concern
without additional mitigation measures. To reduce the potential for metam-sodium and metam-
potassium exposure to bystanders, handlers, and workers and to address associated risks of
concern, EPA is requiring a number of mitigation measures which include:
• Clarifying maximum application rates
• Clarifying use sites;
• Buffer zones;
• Dermal protection for handlers;
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• Respiratory protection and air monitoring for handlers;
• Restrictions on the timing of perforation and removing of tarps;
• Posting;
• Good agricultural practices;
• Fumigant management plans;
• Site specific response and management; and
• Notice to state lead agencies.
The Agency also believes that registrant developed training and community outreach
programs, will help reduce risk. Additionally, EPA is interested in working with registrants to
identify additional measures that could be implemented as part of product stewardship. These
additional measures should include efforts to assist users' transition to the new label
requirements.
Some of the required mitigation measures only address one group of potentially exposed
individuals (i.e., bystanders, handlers, or workers), while other measures will help reduce risk to
more than one group. All mitigation measures are designed to work together to reduce
exposures, enhance safety, and facilitate compliance and enforcement. The Agency has based its
risk mitigation decision on a flexible approach, which EPA believes will be protective and allow
users to make site-specific choices to reduce potential impacts on benefits of the use. While
some of these measures, buffer zones for example, can be used to estimate margins of exposure
(MOEs), others, such as emergency preparedness and response and community education, will
contribute to bystander safety, but are difficult to express in terms of changes to quantitative risk
estimates such as MOEs. However, EPA has determined that these measures, working together,
will prevent unreasonable adverse effects on human health.
aa. Bystander Risk Mitigation
Bystanders are persons who live and/or work near fumigated fields and are potentially
exposed to fumigant emissions that travel off site. In some cases the bystanders are workers
performing agricultural tasks in nearby fields. If they are employed by the grower who has
control of the fumigated field, they are more likely to be aware that a fumigant application has
occurred.
Bystander risks for people that live near treated fields differ from other human health
risks evaluated under FIFRA, for example residential and worker reentry risks. Unlike
residential exposures resulting from use of products to control pests in and around the home,
non-occupational bystanders receive no direct benefit from the pesticide, which was applied
elsewhere. These bystanders have not made a decision to purchase a pest control product or
service, and, as a result, they have little access to information about the product (e.g., hazards,
safety information, first aid, etc.) or symptoms of exposure. Additionally, non-occupational
bystander exposures to fumigants are largely involuntary and unanticipated. In this regard non-
occupational bystander exposure is similar to dietary exposure in that people consuming foods or
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drinking water expect to be safe from possible adverse effects associated with pesticide residues
that could be present in their food and drinking water.
Unlike workers, non-occupational bystanders typically receive no safety information or
training related to the pesticide to which they may be exposed. Whereas workers are generally
expected to play an active role in protecting themselves from pesticide risk, no such expectation
exists for non-occupational bystanders. Workers who experience symptoms of pesticide
exposure are also more likely to link their symptoms to the pesticide and take steps to receive
appropriate treatment. Conversely, bystanders are much less likely to attribute adverse effects to
pesticide exposures or to have access to information needed to take appropriate steps to mitigate
the effects of the exposure. Thus, EPA's mitigation includes elements for emergency
preparedness and response, notice to state lead agencies, training, and community outreach as
well as labeling changes.
The mitigation measures for bystander risks resulting from soil fumigation are described
further in the following sections.
1. Buffer Zones
The human health risk assessments indicate bystanders may be exposed to MITC air
concentrations following metam-sodium and metam-potassium applications that exceed the
Agency's level of concern based on current label requirements. In general, the risk from
inhalation exposures decreases as the distance from the field where bystanders are located
increases. Because of this relationship, the Agency has determined that a buffer zone must be
established around the perimeter of each application block where metam-sodium and metam-
potassium is applied. The Agency acknowledges that buffer zones alone will not mitigate all
risks or eliminate incidents caused by equipment failure, human error, adverse weather (e.g.,
temperature inversions), or other events. The Agency however does believe that buffer zones
along with other mitigation measures required by this decision and described below will mitigate
risks so that bystanders will not experience unreasonable adverse effects.
The Agency considered various buffer zone schemes ranging from fixed buffer zones for
every application to site-specific buffer zones. During the Phase 5 comment period, the Agency
received input in favor of a flexible buffer approach that would allow fumigant users to
determine the buffer zone distance based on site conditions and application practices. While the
Agency believes that site-specific buffer zones would provide the most flexibility for users, the
EPA currently does not have sufficient data to support this scheme. As a result, the Agency has
developed a scalable buffer zone system that does provide flexibility by setting buffer zones for
different application methods at various acreages and application rates.
Version 2.1.4 of the Probabilistic Exposure and Risk model for Fumigants (also called
the PERFUM model) combined with monitoring data and incident data were used to characterize
the risk for specific buffer zone distances corresponding to the range of application scenarios
anticipated. Additional information on the PERFUM inputs and outputs can be found in Agency
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risk assessment, (EPA-HQ-OPP-2005-0123-0285), in a June 2006 a peer-reviewed article
describing the model (http://www.sciencedirect.com/science/journal/13522310), and/or the
PERFUM user's guide which can be download from the internet
(http ://www.exponent, com/perfum/). A CD containing all of the PERFUM input/output files and
files with the PERFUM MOE/air concentration analysis that were considered for this decision
are available upon request at the OPP Docket Office.
(a) Buffer Zone Requirements
General Requirements in the July 2008 RED
The 2008 metam-sodium and metam-potassium RED described general buffer zone
requirements for metam-sodium and metam-potassium and other soil fumigants. This included
the definition of a buffer zone, the requirement to exclude non-handlers from the buffer zone
during the buffer-zone period, and the definition of the application block.
The RED also did not allow buffer zones to overlap and fumigations were prohibited
within !/4 mile of difficult to evacuate sites such as schools, state licensed day care centers,
nursing homes, and hospitals, if occupied during the buffer zone period. Exemptions for
vehicular and bicycle traffic were allowed on roadways through the buffer zone. However, bus
stops or other locations where persons wait for public transit were not permitted within the buffer
zone. Structures within the buffer zone were also not allowed to be occupied during the buffer
zone period and air samples were required before bystanders could enter the structure following
expiration of the buffer-zone period. In addition, before a buffer zone could extend onto
adjacent private or public property, the applicator needed to obtain written permission from the
owner/operator or local authority to allow the buffer zone to extend onto the property. This was
to ensure that non-handlers would not enter the buffer zone and that buffer zones did not overlap.
Comments on the July 2008 RED
During the post-RED comment period, the Agency received many comments from
stakeholders concerning the buffer zone requirements. Many comments stated that the large
buffer zone distances would make fumigation infeasible and the mitigation options were not
flexible enough to allow some fumigations to occur; however other comments expressed concern
that buffers EPA specified would not be large enough to protect bystanders.
The Agency also received numerous comments that buffer zone duration will present
severe hardship for growers. Many commenters expressed concern that the buffer zone overlap
restriction would have the unintended consequence of forcing some applications to occur during
less-than-optimal weather and soil conditions, because the restriction could preclude nearby
application blocks from being treated when weather and soil conditions would be optimal for
reducing emissions. Hence, subsequent fumigations in adjacent fields would have an increased
chance of occurring when weather and soil conditions are more conducive to off-gassing.
Examples cited by commenters where this situation could occur include the Southeast and
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Pacific Northwest where optimal soil moisture conditions occur during a limited time period.
The commenters felt that while the buffer zone is in effect, properly trained and equipped
handlers should be allowed to enter adjacent application blocks to make applications. Several
commenters felt that providing an exception to this prohibition would make buffers more
workable, reduce delays, allow a more efficient use of equipment and labor, allow growers
additional flexibility to achieve compliance with buffer requirements, and potentially reduce risk
if applications could be made under more favorable soil and weather conditions. In addition,
some comments suggested that allowing adjacent application blocks to be treated would not
increase risk to bystanders since the Agency's mitigation measures encourage users to split
application blocks into smaller treatment areas which result in less fumigant being applied, less
exposure, and less potential risk.
Some comments also asked for clarification on various aspects of the buffer zone
requirements, and some asked that EPA provide additional increments for acreages and
application rates for buffer zone tables. In addition, many comments stated that buffer zone
credits should be greater for the use of tarps and for certain environmental conditions. A number
of comments indicated that obtaining written permission from local authorities for buffers to
extend over roads and rights-of-way would be extremely difficult, and that neighbors may not
provide permission. EPA also received additional field emissions (flux) data for some
fumigants, as well as additional information regarding factors that affect fumigant emissions.
Based on EPA's review of the comments, and new data and information, the Agency has
determined that certain amendments to the buffer zone requirements are appropriate. EPA
believes these amendments will maintain the important protections for bystanders but will
increase the feasibility of compliance with buffers and will reduce potential impacts of buffers on
the beneficial uses of soil fumigants. The Agency does agree that compliance with buffer zone
requirements as outlined in the July 2008 RED would be a significant challenge for applicators
and growers. However, field flux studies, monitoring data, modeling analyses, and information
from incidents involving fumigants continue to support a conclusion that metam-sodium and
metam-potassium off-gasses and moves away from treated fields at concentrations that have the
potential to cause adverse effects. Therefore, the Agency still believes that buffer zones that
exclude bystanders are a critical aspect of mitigating risks from the use of metam-sodium and
metam-potassium. The Agency believes the modifications to the buffer requirements, specified
below, will increase compliance feasibility and encourage further adoption of emission reduction
application techniques, while still protecting human health and the environment.
Amended RED Requirements
EPA has determined that no changes to several aspects of the general buffer zone
requirements from the 2008 RED are appropriate. This includes
the definition and duration of a buffer zone;
the requirement to exclude field workers, nearby residents, pedestrians, and other
bystanders from the buffer zone during the buffer zone period (except for transit);
- the definition of the application block;
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the minimum buffer of 25 feet and maximum buffer of 1A mile.
the requirement limiting entry into buffer zones to handlers who have been properly
trained and equipped according to EPA's Worker Protection Standard;
the exemption for transit through buffer zones;
the prohibition on including in buffer zones bus stops or other locations where
persons wait for public transit;
the prohibition against including in buffer zones buildings under the control of the
owner/operator of the application block used for storage such as sheds, barns,
garages, etc., unless the storage buildings are not occupied during the buffer zone
period, and the storage buildings do not share a common wall with an occupied
structure;
the prohibition against including in buffer zones residential areas that are not under
the control of the owner/operator unless occupants agree in writing that they will
voluntarily vacate the buffer zone until the buffer zone period expires;
the prohibition against including in buffer zones agricultural areas that are not under
the control of the owner/operator unless the owner/operator of the other area provides
written agreement that they, their employees, and other persons will not enter the
buffer zone; and
the prohibition against including in buffer zones publicly owned and/or operated
areas such as parks, sidewalks, walking paths, playgrounds, and athletic fields
without first obtaining written permission from local authorities.
EPA has determined that certain other amendments to the July 2008 RED requirements
are appropriate; these are discussed in greater detail below. The amended buffer zone
requirements are summarized at the end of this section.
Buffer Zone Proximity - Exception to Allow Buffer Zone Overlap
The Agency is concerned that emissions from multiple fields located close to one another
could be higher than air concentrations from individually treated fields. As a result, bystanders
outside of buffers for individual application blocks could be exposed to concentrations of
concern particularly if peak concentrations from multiple application blocks in proximity to each
other coincide. To reduce the potential for off-site movement of fumigant emissions beyond
buffer zones for multiple fumigated fields, the July 2008 RED prohibited buffer zones from
multiple application blocks from overlapping, including application blocks fumigated by other
property operators.
EPA has considered the comments submitted and has determined that allowing an
exception to the buffer zone overlap prohibition, under the conditions specified below, is
reasonable and will not demonstrably alter the protection goals provided to bystanders in the July
2008 RED. EPA has determined that buffer zones from nearby and adjacent application blocks
may overlap one another provided at least 12 hours have elapsed from the end of one application
until the start of the next application. By separating the application times by at least 12 hours the
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fumigant emission peaks are less likely to occur at the same time which would sufficiently
reduce potential exposure outside buffer zones and meets the Agency's protection goals.
The Agency is maintaining the requirement for buffer zones around each application
block to be in effect for 48 hours, as well as the requirement that only properly trained and
equipped handlers are allowed to enter into buffers zones.
To clarify, below are conditions when buffer zones may or may not overlap:
• A buffer zone may NOT overlap buffer zones from other application blocks that
are already in effect UNLESS a minimum of 12 hours has elapsed from the time
the first application ends until the second application begins.
Metam only: Applications of metam-sodium and metam-potassium can take place on
large fields, typically greater than 80 acres, and may require several days to complete (e.g., via
center pivot or lateral move irrigation systems). In situations where such large field sizes are
treated the offsite movement of emissions may be proportionately less, on an acre basis, than
smaller fields because the fetch (i.e., area over which emissions are diluted) for certain areas of
such fields would be either contained totally within the boundaries of the field or it would allow
for significant dilution as the emissions move from the application block offsite into the buffer
zone. As a result of the time requirements involved in treating such large areas and the reduced
per acre contributions to overall emissions on large fields, EPA believes there is less potential
for peak emissions from multiple large applications blocks to coincide and result in
concentrations of concern outside adjacent buffers within localized areas than would be expected
if the situation varied by larger numbers of smaller fields being treated that would more likely
result in coincidental peak emissions (e.g., fields that take no more than one day to treat and that
are smaller in acreage).
Although current modeling supports a conclusion that as application block size increases,
the emissions into the buffer areas are reduced on a per acre basis, the data to support a robust
analysis of this relationship is very limited at this time. Based on comments provided, EPA also
recognizes that compliance with the prohibition on buffer overlap in areas such as the Pacific
Northwest with large-scale production systems based on center pivot applications would be
extremely challenging for metam users. EPA also understands that, due to the length of time
needed to complete these applications, separating applications by 12 hours is also impractical.
EPA also wishes to encourage adoption of improved application techniques such as low release
center pivot systems because it believes that their use will reduce the potential for exposures of
concern because they reduce droplet drift potential for those in proximity to fields and may
reduce application rates as well because of more effective water delivery. Based on these
considerations, the Agency has determined that buffer zones may overlap for center-pivot
application blocks only if each block is treated using low release center pivot systems which will
increase the feasibility of compliance with buffer zone requirements and will not demonstratively
alter the protection provided to bystanders.
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The Agency is maintaining the requirement for buffer zones around each application
block to be in effect for 48 hours and that only properly trained and equipped handlers are
allowed to enter into buffers zones.
To clarify, below are conditions when buffer zones may or may not overlap:
• A buffer zone may NOT overlap buffer zones from other application blocks that
are already in effect UNLESS a minimum of 12 hours has elapsed from the time
the first application ends until the second application begins.
Metam Only: For Low Release Center Pivot Applications only:
• A buffer zone may NOT overlap buffer zones from other application blocks
which are already in effect UNLESS both application blocks are treated using low
release center pivot systems. The 12 hour waiting period does not apply in this
instance.
EPA has determined that when fumigators exercise the exception to allow buffers to
overlap, the emergency preparedness and response measures described later in this document
must be implemented if there are homes, businesses, or property not within the control of the
fumigator within 300 feet of the buffer zone.
To ensure handlers are aware that they are working in an existing buffer from an
overlapping buffer zone area, the labels will require the certified applicator, before beginning the
application, to determine whether the application block or its resulting buffer will overlap with a
buffer that is already in effect. If so, the certified applicator must inform handlers of this and the
health effects, early signs of exposure, and respiratory protection and PPE requirements for
products applied in both the application block in which they are working and the other
application block. The Agency is requiring that all treatment areas and buffers be clearly posted
with proper signage to ensure handlers entering a treatment area are aware of previous treatments
and the existence of buffers. In addition, certified applicators must obtain permission from other
landowners when buffers extend onto other lands which provides an additional mechanism to
ensure handlers are aware when they are working in a buffer zone and that they have the
necessary information regarding health effects, warning properties, and respiratory/PPE
requirements for all products they may be exposed to.
Areas not under the control of owner/operator of the application block
For areas not under the control of the owner/operator of the application block, the
requirements remain unchanged except (1) air samples do not need to be taken to allow
occupants to reenter buildings or homes after the buffer zone period has expired, and (2) buffer
zones may include publicly owned and/or operated roads, including rights of ways, without first
obtaining written permission from local authorities; however, if a sidewalk or permanent walking
49
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path is associated with the road or right-of-way, written permission must be given by the
appropriate state and/or local authorities.
In summary, areas of a buffer zone not under the control of the owner/operator of the
application block, may not include residential areas (including employee housing, private
property, buildings, commercial, industrial, and other areas that people may occupy or outdoor
residential areas, such as lawns, gardens, or play areas) unless the occupants provide written
agreement that they will voluntarily vacate the buffer zone during the entire buffer zone period.
The Agency determined that the concentrations of the fumigants 48 hours after completion of the
application were likely to be below the Agency's level of concern, and that the warning
properties of MITC would alert persons reentering these sites if concentrations had not yet
dissipated. Therefore, monitoring of buildings and outdoor areas after termination of the buffer
zone is not necessary and will no longer be required.
Buffer zones may still not include agricultural areas owned/operated by persons other
than the owner/operator of the application block unless the owner/operator of the application
block can ensure that the buffer zone will not overlap with a buffer zone from any adjacent
property owners, taking into account the amended requirements for overlapping buffers. In
addition, the applicator must still receive written permission from the owner/operator of areas
that are not under the control of the applicator stating that the owner, their employees, and other
persons other than handlers, consistent with buffer overlap provisions, will stay out of the buffer
zone during the entire buffer zone period. The goal of this agreement is to ensure that a property
owner of an agricultural field adjacent to an area that will be treated with a fumigant is aware
when the fumigation will occur. This will allow the applicator to post on the adjacent property
and take other required safety measures to ensure that persons on the property will not be
exposed to a fumigant at levels above the Agency's level of concern. Informing the property
owner of the adjacent field will enable them to take any appropriate safety measure. The Agency
believes that requiring the applicator obtain written permission will be an enforceable measure
that will meet the goal of protecting workers and bystanders on adjacent properties that fall
within a buffer zone.
In addition, buffer zones still may include publicly owned and/or operated areas such as
parks, sidewalks, walking paths, playgrounds, and athletic fields only if the area is not occupied
during the buffer zone period and entry by non-handlers is prohibited during the buffer zone
period. Written permission from the appropriate state and/or local authorities to include those
public areas in the buffer zone is also still required.
However, for roads and rights-of-ways, EPA has determined that these may be included
in buffers, subject to local laws and regulations, as long as it is posted according to the
requirements of this amended RED. If, as discussed above, the road or right-of-way has an
associated sidewalk or permanent walking path, then written permission would also be required
to include the area in the buffer zone. The Agency believes that if a town or county has invested
resources into building a sidewalk or establishing a walking path, it is reasonable to anticipate
pedestrian traffic at that location. In such circumstances EPA believes a local authority would be
50
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best positioned to make a determination about the practicality of preventing non-handlers from
entering the buffer zone. EPA acknowledges that laws and regulations vary from jurisdiction to
jurisdiction and that the requirement to post points of entry into buffer zones may necessitate
additional steps on the part of fumigant applicators before a road or right-of-way can be included
in a buffer.
(b) PERFUM Model Inputs
The major input parameters for the modeling are: application rates, application block
sizes, application method emission profiles, weather conditions, and the target air concentration
(based on acute inhalation endpoint and uncertainty factors). The following summarizes the key
points for each of these input parameters.
Application Rates
The Agency modeled up to 320 Ib ai/acre for all metam applications, the maximum
application rate permitted on the metam product labels. However, typical application rates vary
by crop and geographic region. According to EPA proprietary data for 2004-2005,
approximately 94% of metam-sodium was applied at a rate of 225 Ib ai/acre or less. OPP's
Biological and Economic Analysis Division (BEAD) completed a series of benefits assessments
by crop and region that included a more detailed analysis of use rates and are available for
review in the metam-sodium docket (EPA-HQ-OPP-2005-0125) at www.regulations.gov.
Rates for bedded or strip applications (Ib ai per treated area) were converted to broadcast
equivalent application rates to determine the minimum buffer zone distance. In Figures 1 and 2
(shown below), the dashed line represents the perimeter of the field, the shaded area is the
portion of the field that is treated, and the un-shaded area is the area of the field that is untreated.
As an example, assume that both fields are 10 acres, and only 50% of field in Figure 2 is
fumigated, and the rate per treated acre is 400 Ibs ai/A for both Figure 1 and 2. In this case, the
broadcast rate for Figure 1 is 400 Ib ai/A but the effective broadcast equivalent rate for Figure 2
is 200 Ibs ai/A. Labels may express rates as Ibs per treated acre under the application
instructions but they must identify buffer zone distances based on the broadcast or effective
broadcast equivalent rates. [Note: In the risk assessment, a 60% value for proportion of field
treated was used in the calculations.]
51
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mi
Figure 1. Broadcast Application Figure 2. Bedded Application
Application Block Sizes
For all application methods, the Agency modeled up to 120 acres, which is the limit of
the PERFUM model. However, typical application block sizes vary by crop and geographic
region. In the Pacific Northwest, crops are typically grown in fields averaging 120-acres in size,
while crops in California, the upper Midwest, and the Southeast tend to be smaller, typically 10-
60 acres, 30-50 acres, and 10-40 acres respectively. OPP's Biological and Economic Analysis
Division (BEAD) completed a series of benefits assessments by crop and geographic region that
included a more detailed analysis of typical application block sizes, which are available for
review in the metam-sodium docket (EPA-HQ-OPP-2005-0125) at www.regulations.gov.
The application block size pertains to size of the field and not the size of the area treated.
The area inside the dashed lines in both Figures 1 and 2 is the application block. In this example
the application block size for both figures is 10 acres. For both figures, 10 acres would be used
to determine the buffer zone distance.
During the post-RED comment period, the Agency received comments requesting buffer
zone distances for additional acreage increments for small fields. In response, the Agency
determined buffer distances for smaller block sizes (1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 acres.
Although the Agency added additional acreage and rate increments, not all increments may be
captured by the tables presented. If the tables do not capture a specific acreage or rate, round up
to the nearest acre or rate. For example, when applying to a 9.5 acre field, round up to 10 acres.
Emission Studies
The Agency's risk assessment for the July 2008 RED included modeling of four pre-plant
soil application methods: (1) sprinkler irrigation (with standard2 and intermediate3 water seals),
(2) shank injection (with standard1 and intermediate2 water seals, compaction, and standard
A standard water seal consisted of either a l/i inch of water added immediately after an application and another i/2-
inch of water applied within 24 hours of the application (chemigation study) or a 1A inch of water applied within 24
hours of the application (shank injection study).
3 An intermediate water seal consisted of a 1A inch of water applied immediately after application, two additional 1A-
inch water seals applied the same day as the application, as well as three additional '/i-inch water seals applied the
day following application.
52
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polyethylene tarps), (3) drip irrigation (with and without standard polyethylene tarps), and (4)
flood irrigation. The modeling performed by EPA was based on 14 field volatility studies. The
majority of these studies were conducted in California (11), with several also conducted in
Florida (2) and Washington (1).
While the Agency considered the modeling data from all 14 emissions studies available,
it used a subset of the most representative emissions studies to serve as the basis for developing
the buffer zone distances. These studies included: (1) the Bakersfield, CA, sprinkler irrigation
study with intermittent water seal (USDA CSREES Project #74; 09/02); (2) the Bakersfield, CA,
shank injection study with intermittent water seal (USDA CSREES Project #74; 09/02); (3) the
Citra, FL, drip irrigation study with tarps (USDA CSREES Project #74; 02/03); and (4) the
Brawley, CA, flood irrigation study (MRID 473143-01). For application methods where the
Agency does not currently have emissions study data available, these emissions study profiles
also served as surrogate data. The buffer zone distances for all chemigation and the low-release
height and low-drift center pivot applications were derived from the sprinkler irrigation emission
study profile with intermittent water seal. It should be noted that the Agency does not believe
that the sprinkler irrigation study emissions data are representative of the high-release height
center pivot application method (which includes use of end guns). However, the Agency has
selected buffer zone distances for this application method that it believes are sufficiently
protective of bystander risk. Washington State University has submitted studies to quantify the
flux rate for metam-sodium and metam-potassium from shank injection applications and from
center pivot applications using a drizzle boom in the Pacific Northwest. These studies were
submitted in April, 2009, and are currently in review. If these studies indicate that the buffer
zones for these types of applications should be modified, the Agency will update the buffer
tables prior to implementation of new labeling related to buffers for metam sodium in 2011. The
results of these studies have not been included in this amended document and the buffer tables
below. EPA is requiring the registrants to submit studies to quantify the flux rate for metam-
sodium and metam-potassium from center pivot applications using low-, medium- and high-
release equipment, both with and without the use of endguns. The Agency will include the
results of this research in its final labeling decisions, if possible.
Based on the site characteristics (i.e., maximum air temperature, maximum soil
temperature, field capacity) of the field volatility studies that served as the basis for the buffer
zone distances, the profiles modeled for both the sprinkler irrigation (with intermediate water
seals) and shank injection (with intermediate water seals) scenarios, were assumed to represent
high-end but not necessarily the worst case for metam applications in the U.S. The profiles
modeled for both the drip and flood irrigation scenarios, which served as the basis for the buffer
zone distances, were assumed to represent more "typical" site characteristics. The Agency
believes that several required GAPs, including mandatory soil temperature and soil moisture
requirements, will greatly reduce the likelihood that worst case scenarios will occur.
Weather
53
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The largest use of metam-sodium and metam-potassium for soil fumigation in the U.S.
occurs in the Pacific Northwest and California, followed by the upper Midwest and the
Southeast. Based on these high-use areas, six weather station data sets were modeled (Ventura,
CA; Bakersfield, CA; Bradenton, FL; Tallahassee, FL; Flint, MI; and Yakima, WA). Each
modeling run used five years of weather data (e.g., 1,825 potential application days) for each
location. Generally, Ventura, and Bradenton weather data result in the largest buffer zone
distances, followed by Bakersfield and Tallahassee. Flint data result in significantly smaller
buffers.
Target Air Concentrations
As described in the Human Health Risks section of Section III, the 22 ppb target air
concentration is based on a reversible sensitive endpoint from a human eye irritation and odor
threshold study for acute exposures to MITC, with a 10X human variability uncertainty factor for
intraspecies extrapolation. The lowest observable adverse effect level (LOAEL) is 800 ppb, and
the human concentration (HC) based on the no observable adverse effect level (NOAEL) from
this study is 220 ppb.
The Agency focused on achieving an MOE of 10 at upper percentiles of each of the
distributions from the PERFUM modeling outputs. However, the buffer zone distances required
to achieve this MOE would have been prohibitively large and likely would have been impossible
for most growers to implement. The Agency believes that the buffer zone distances being
required, in addition to the other mitigation requirements described herein (i.e., restricted use
pesticide classification, posting and emergency preparedness procedures for buffer zones,
mandatory good agricultural practices, required fumigant management plans, soil fumigant
training requirements for applicators and handlers, and ambient air monitoring programs in high-
use areas), adequately address the risk of acute fumigant exposure to bystanders and will greatly
reduce the magnitude and frequency of exposure incidents.
(c) PERFUM Model Outputs
The PERFUM model outputs are presented in percentiles for "whole field" and the
"maximum distance" distributions. The model also provides outputs as distributions of air
concentrations from which margins of exposure (MOEs) can be estimated. The following
summarizes the key points for each of these output parameters.
The maximum distance distribution is a compilation of the farthest predicted buffer
distances (i.e., the farthest downwind points) over 5 years of weather, and the whole field
distribution, as described, differs because it includes all points around the perimeter for the same
period. It also should be noted that another way to consider this is that maximum buffer results
are a subset of the whole field results and that maximum distances allow for more resolution at
the upper percentiles of this distribution. Version 2.1.4 of PERFUM also allows for direct
consideration of air concentrations at various distances around treated fields. These values were
also considered in the decision-making process.
54
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An analysis based on a variety of PERFUM outputs was used in the buffer distance
determinations. This involved consideration of the typical maximum and whole-field results,
which are predictions of the distances at which a target concentration of concern (i.e., the human
equivalent concentration adjusted by applicable uncertainty factors) is achieved at varying
percentiles of exposure. In addition, a complementary approach, which determined the
percentiles of exposure for maximum and whole-field buffers at predetermined buffer distances,
was employed. Air concentration data were also used to calculate risk estimates (i.e., margins of
exposure) at predefined buffer distances and varied percentiles of exposure.
This overall approach allowed the Agency to utilize more of the information available
from PERFUM so that a more comprehensive view of the risks could be considered. Buffer
distances indicated by this type of analysis along with information from monitoring studies and
incidents were valuable in determining buffer distances to manage potential risks from metam-
sodium and metam-potassium use when coupled with other mitigation measures.
Buffer Zone Distances
The Agency has developed required buffer zone distances based on application method,
application rate, and application block size (rounding up to nearest whole units for application
rate and block size). These distances are summarized in Tables 5 to 11 below.
For each of the outdoor pre-plant soil emission profiles, distances were first chosen for
the rates identified in the risk assessment as the 10%, 25%, 50%, 75% and 100% of the
maximum rates (i.e., 32, 80, 160, 240, and 320 Ib ai/A for all metam applications), each paired
with application block sizes of 5, 10, 20, 30, 40, 50, 60, 80, 100, and 120 acres. Distances for
the other rates in the buffer zone tables were scaled by assuming a linear relationship between
the 10%, 25%, 50%, 75% and 100% maximum label rates [e.g., distance at 37.5% rate =
(distance at 25% rate + distance at 50% rate)/2]. This scaling was necessary to provide an
incremental spread of rates. It should be noted that the distances in the lookup tables are not
model outputs, although the model outputs were a tool used for their development. A description
of how the model outputs were used to characterize the buffer zone distances is provided
immediately after the buffer zone look-up tables (Tables 5 to 11).
• Minimum and Maximum Distances
A minimum buffer zone of 25 feet will be required regardless of site-specific application
parameters. In some instances, the PERFUM model predicts that the risks reach the target at the
edge of the field, but the Agency believes that a 25-foot minimum buffer is a good agricultural
practice. While modeling may support no buffer in some cases, a minimum buffer is being
required because of variability in emission rate over a field and other factors not accounted for in
the modeling. Conversely, application scenarios requiring buffers zone distances of more than 1A
mile (2,640 feet) are prohibited. EPA believes that for areas where metam-sodium and metam-
potassium are used, buffers greater than /^ mile are not practical and difficult to enforce.
55
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The buffer zone distances were not based on the selection of a specific percentile or
distribution from the PERFUM modeling results. Rather, EPA used a weight of evidence
approach to set the buffers that included consideration of the hazard profile of metam-sodium
and metam-potassium, information from incident reports, monitoring data, and stakeholder
comments along with comprehensive analysis of results from PERFUM modeling and
consideration of results using other models (e.g., Industrial Source Complex Model). The
analysis of PERFUM results considered distances at various percentiles of the whole field and
maximum distance distributions as well as and predicted MOEs for various distances. The risk
assessment characterizes additional types of analysis that were performed. The following
characterizes the risks associated with the buffer zone distances summarized in Tables 5 to 11.
The buffer zone distances at the 90th percentile maximum distribution is equivalent to
saying a person at the location on the perimeter of the buffer zone where the maximum
concentration occurs during the worst case 24-hour period following the fumigation of a specific
field during a 5-year period would have at least a 90% chance of exposure below the level of
concern. The buffer zone distances at the 90th percentile whole field distribution is equivalent to
saying a person somewhere on the perimeter of the buffer zone during the worst case 24-hour
period following the fumigation of a specific field during a 5-year period would have at least a
90% chance of exposure below the level of concern. The risk assessment, available in the
metam-sodium/potassium docket (EPA-HQ-OPP-2005-00125) at www.regulations.gov,
characterizes additional types of analysis that were performed.
Note: Washington State University has submitted studies to quantify the flux rate for metam-
sodium and metam-potassium from shank injection applications and from center pivot
applications using a drizzle boom in the Pacific Northwest. These studies were submitted in
April, 2009, and are currently in review. If these studies indicate that the buffer zones for these
types of applications should be modified, the Agency will update the buffer tables prior to
implementation of new labeling related to buffers for metam sodium in 2011. The results of
these studies have not been included in this amended document and the buffer tables below.
56
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Table 5. 2008 Center Pivot Irrigation Application (High Release Height*)
Buffer Zone Distance in Feet
Block
Size
(A)
1
5
10
20
30
40
50
60
70
80
90
100
110
120
140
160
Application Rate (Ib ai/A)
32
50
50
50
75
75
100
100
200
200
200
250
300
350
400
600
800
56
80
100
100
138
138
200
200
300
300
300
350
400
450
500
700
900
SO
125
150
150
200
200
300
300
400
400
400
450
500
550
600
800
1000
100
160
188
200
250
269
363
382
475
488
500
550
600
650
700
900
1100
120
185
225
250
300
338
425
463
550
575
600
650
700
750
800
1000
1200
140
205
263
300
350
407
488
544
625
663
700
750
800
850
900
1100
1300
160
220
300
350
400
475
550
625
700
750
800
850
900
950
1000
1200
1400
180
235
313
375
450
557
638
719
825
888
950
1000
1050
1100
1150
1350
1550
200
250
325
400
500
638
725
813
950
1025
1100
1150
1200
1250
1300
1500
1700
220
262
338
425
550
719
813
907
1075
1163
1250
1300
1350
1400
1450
1650
1850
240
275
350
450
600
800
900
1000
1200
1300
1400
1450
1500
1550
1600
1800
2000
260
288
363
488
650
850
975
1100
1300
1400
1500
1563
1625
1688
1750
1950
2150
280
300
375
525
700
900
1050
1200
1400
1500
1600
1675
1750
1825
1900
2100
2300
300
312
389
563
750
950
1125
1300
1500
1600
1700
1788
1875
1963
2050
2250
2450
320
325
400
600
800
1000
1200
1400
1600
1700
1800
1900
2000
2100
2200
2400
2600
* This buffer zone distance table is for center pivot irrigation equipment in which the: 1) release height
greater than 8 feet, and 2) there is > 30 Ibs psi at the sprinkler head.
57
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Table 6. 2008 Center Pivot Irrigation Application (Medium Release Height**)
Buffer Zone Distance in Feet
Block
Size
(A)
1
5
10
20
30
40
50
60
70
80
90
100
110
120
Application Rate (Ib ai/A)
32
25
25
25
25
25
50
50
75
75
75
88
100
150
200
56
25
38
50
50
50
75
75
138
138
138
169
200
250
300
SO
25
50
75
75
75
100
100
200
200
200
250
300
350
400
100
37
63
94
107
125
163
182
275
288
300
350
400
450
500
120
50
75
113
138
175
225
263
350
375
400
450
500
550
600
140
62
88
132
169
225
288
344
425
463
500
550
600
650
700
160
75
100
150
200
275
350
425
500
550
600
650
700
750
800
180
87
113
175
250
357
438
519
625
688
750
800
850
900
950
200
100
125
200
300
438
525
613
750
825
900
950
1000
1050
1100
220
112
138
225
350
519
613
707
875
963
1050
1100
1150
1200
1250
240
125
150
250
400
600
700
800
1000
1100
1200
1250
1300
1350
1400
260
138
263
288
450
650
775
900
1100
1200
1300
1363
1425
1488
1550
280
150
175
325
500
700
850
1000
1200
1300
1400
1475
1550
1625
1700
300
162
188
363
550
750
925
1100
1300
1400
1500
1588
1675
1763
1850
320
175
200
400
600
800
1000
1200
1400
1500
1600
1700
1800
1900
2000
** This buffer zone distance table is for center pivot irrigation equipment in which the: 1) release height
AND spray height is less than 8 feet, AND 2) 291bs. or less PSI at the sprinkler head, AND 3) there are no
end guns.
58
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Table 7. 2008 Center Pivot Irrigation Application (Low Release Height***)
Buffer Zone Distance in Feet
Block
Size
(A)
1
5
10
20
30
40
50
60
70
80
90
100
110
120
Application Rate (Ib ai/A)
32
25
25
25
25
25
25
25
50
63
75
88
100
125
150
56
25
25
38
38
38
50
50
75
100
125
138
150
188
225
SO
25
25
50
50
50
75
75
100
138
175
188
200
250
300
100
30
35
63
70
75
107
119
150
192
232
254
275
325
375
120
35
50
75
89
100
138
163
200
244
288
319
350
400
450
140
40
63
88
107
125
169
207
250
297
344
385
425
475
525
160
50
75
100
125
150
200
250
300
350
400
450
500
550
600
180
60
94
125
157
188
238
294
363
419
475
532
588
644
700
200
70
113
150
188
225
275
338
425
488
550
613
675
738
800
220
85
132
175
438
263
313
382
488
557
625
694
763
832
900
240
105
150
200
250
300
350
425
550
625
700
775
850
925
1000
260
125
163
225
288
350
413
494
613
694
775
857
938
1019
1100
280
145
175
250
325
400
475
563
675
763
850
938
1025
1113
1200
300
165
188
275
363
450
538
632
738
832
925
1019
1113
1207
1300
320
185
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
*** This buffer zone distance table is for center pivot irrigation equipment in which the: 1) release height
AND spray height is less than 4 feet, AND 2) 291bs. or less PSI at the sprinkler head, AND 3) solid
stream nozzle (e.g. drizzle boom, Smart Drop, etc.), AND 4) there are no end guns.
59
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Table 8. 2008 All Chemigation Except Center Pivot
and Flood Applications Buffer Zone Distance In Feet
Block
Size
(A)
1
2
3
4
5
6
7
8
9
10
20
30
40
50
60
70
80
90
100
110
120
Application Rate (Ib ai/A)
32
25
25
25
25
25
25
25
25
25
25
25
25
50
50
75
75
75
88
100
150
200
56
38
38
38
38
38
40
43
45
48
50
50
50
75
75
138
138
138
169
200
250
300
SO
50
50
50
50
50
55
60
65
70
75
75
75
100
100
200
200
200
250
300
350
400
100
55
57
58
60
63
69
75
81
87
94
107
125
163
182
275
288
300
350
400
450
500
120
62
65
67
70
75
83
90
98
105
113
138
175
225
263
350
375
400
450
500
550
600
140
68
73
78
83
88
97
106
114
123
132
169
225
288
344
425
463
500
550
600
650
700
160
75
81
88
94
100
110
120
130
140
150
200
275
350
425
500
550
600
650
700
750
800
180
80
88
97
105
113
125
138
150
163
175
250
357
438
519
625
688
750
800
850
900
950
200
87
97
106
116
125
131
140
146
155
200
300
438
525
613
750
825
900
950
1000
1050
1100
220
93
104
116
127
138
155
173
190
208
225
350
519
613
707
875
963
1050
1100
1150
1200
1250
240
100
113
125
138
150
170
190
210
230
250
400
600
700
800
1000
1100
1200
1100
1300
1350
1400
260
115
152
189
226
263
268
273
278
283
288
450
650
775
900
1100
1200
1300
1363
1425
1488
1550
280
125
138
150
163
175
205
235
265
295
325
500
700
850
1000
1200
1300
1400
1475
1550
1625
1700
300
137
150
163
175
188
223
258
293
328
363
550
750
925
1100
1300
1400
1500
1588
1675
1763
1850
320
150
163
175
188
200
240
280
320
360
400
600
800
1000
1200
1400
1500
1600
1700
1800
1900
2000
60
-------
Table 9. 2008 Shank Injection Applications-Tarped and Untarped
Buffer Zone Distance In Feet
Block
Size
(A)
1
2
3
4
5
6
7
8
9
10
20
30
40
50
60
70
80
90
100
110
120
Ap
32
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
38
50
63
75
75
75
44
25
25
25
25
25
25
25
25
25
25
25
32
32
38
38
51
63
76
88
91
94
56
25
25
25
25
25
25
25
25
25
25
25
38
38
50
50
63
75
88
100
107
113
68
25
25
25
25
25
25
25
25
25
25
25
44
44
63
63
76
88
100
113
123
132
SO
25
25
25
25
25
25
25
25
25
25
25
50
50
75
75
88
100
113
125
138
150
100
25
25
25
25
25
26
28
29
31
32
32
57
57
82
82
104
125
138
150
163
175
120
25
25
25
25
25
28
30
33
35
38
38
63
63
88
88
119
150
163
175
188
200
plication Rate (Ib ai/A)
140
25
25
25
25
25
29
33
36
40
44
44
69
69
94
94
135
175
188
200
213
225
160
25
25
25
25
25
30
35
40
45
50
50
75
75
100
100
150
200
213
225
238
250
180
32
32
32
32
32
38
44
51
57
63
69
113
119
150
163
207
250
266
282
298
313
200
38
38
38
38
38
45
53
60
68
75
88
150
163
200
225
263
300
319
338
357
375
220
44
44
44
44
44
53
62
70
79
88
132
188
207
250
288
319
350
372
394
416
438
240
50
50
50
50
50
60
70
80
90
100
175
225
250
300
350
375
400
425
450
475
500
260
56
58
60
61
63
75
88
100
113
125
207
257
288
350
413
444
475
500
525
550
575
280
63
66
69
72
75
90
105
120
135
150
238
288
325
400
475
513
550
575
600
625
650
300
69
74
79
83
88
105
123
140
158
175
269
319
363
450
538
582
625
650
675
700
725
320
75
81
88
94
100
120
140
160
180
200
300
350
400
500
600
650
700
725
750
775
800
61
-------
Table 10. 2008 Rotary Tiller and Spray Blade Applications
Buffer Zone Distance In Feet
Block
Size
(A)
1
5
6
7
8
9
10
20
30
40
50
60
70
80
Application Rate (Ib ai/A)
32
25
25
25
25
25
25
25
25
25
25
25
25
25
25
56
25
25
25
25
25
25
25
25
25
25
25
25
25
25
SO
25
25
25
25
25
25
25
25
25
25
25
25
25
25
100
25
25
25
25
25
25
25
25
25
25
25
25
25
25
120
25
25
25
25
25
25
25
25
25
25
25
25
25
25
140
25
25
25
25
25
25
25
25
25
25
25
25
25
25
160
25
25
25
25
25
25
25
25
25
25
25
25
25
25
180
25
25
25
25
25
25
25
25
25
25
42
57
64
72
200
25
25
25
25
25
25
25
25
25
25
58
88
103
118
220
25
25
25
25
25
25
25
25
25
25
74
119
142
164
240
25
25
25
25
25
25
25
25
25
25
90
150
180
210
260
25
25
27
29
30
32
34
49
64
75
135
188
218
248
280
25
25
29
32
36
39
43
73
103
125
180
225
255
285
300
25
25
30
36
41
47
52
97
142
275
225
263
293
323
320
25
25
32
39
46
53
60
120
180
225
270
300
330
360
62
-------
Table 11. 2008 Drip Irrigation Applications-Tarped and Untarped
Buffer Zone Distance in Feet
Block
Size
(A)
1
2
3
4
5
6
7
8
9
10
20
30
40
50
60
70
80
Ap
32
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
56
25
25
25
25
25
25
25
25
25
25
38
38
50
50
63
76
88
SO
25
25
25
25
25
25
25
25
25
25
50
50
75
75
100
125
150
100
25
25
25
25
25
26
28
29
31
32
57
57
82
82
113
140
163
120
25
25
25
25
25
28
30
33
35
38
63
63
88
88
125
150
175
140
25
25
25
25
25
29
33
36
40
44
69
69
94
94
138
163
188
plication Rate (Ib ai/A)
160
25
25
25
25
25
30
35
40
45
50
75
75
100
100
150
175
200
180
25
27
29
30
32
37
42
47
52
57
82
94
113
125
175
207
238
200
25
28
32
35
38
43
48
53
58
63
88
113
125
150
200
250
275
220
25
30
35
39
44
49
54
59
64
69
94
132
138
175
225
269
313
240
25
31
38
44
50
55
60
65
70
75
100
150
150
200
250
300
350
260
32
37
41
46
50
56
63
69
76
82
125
188
200
250
300
350
400
280
38
41
44
47
50
58
65
73
80
88
150
225
250
300
350
400
450
300
44
46
47
49
50
59
68
76
85
94
175
263
300
350
400
450
500
320
50
50
50
50
50
60
70
80
90
100
200
300
350
400
450
500
550
For all pre-plant soil applications for metam-sodium/potassium, the buffer zone distances
necessary to achieve the target MOE (an MOE of 10), for all weather station data modeled, are
prohibitively large and would likely be impossible for most growers to implement. The Agency
worked to balance the need to develop buffer zone distances that are sufficiently protective with
the benefits that accrue from the use of metam-sodium/metam-potassium. The Agency believes
that the buffer zone distances it has selected, combined with the other mitigation measures
described herein (e.g., requiring GAPs and FMPs; posting and emergency preparedness
requirements; soil fumigant training requirements for applicators and handlers; clarifying use
sites and ambient air monitoring programs in high-use areas) will adequately address the risk of
acute exposure to bystanders and will greatly reduce the magnitude and frequency of exposure
incidents.
The Agency selected the buffer zone distances for metam-sodium/metam-potassium, such
that the resulting MOEs are > 3 for all application methods and all weather stations data. While
this does not meet the target air concentration for the buffer zone distances, even at the lowest
MOE (MOE of 3), the predicted air concentration at the edge of the buffer would be 12 times
lower than the lowest observable adverse effect level (LOAEL), which is the level at which eye
irritation effects begin in humans.
63
-------
The table below (Table 12) shows the buffer distances and risk characterization for some
key use scenarios, based on crop, region, typical application rate, and typical application block
size. It also shows the percentile for the whole field and max distribution for each distance, as
well as the MOE at the 95th percentile air concentration of PERFUM.
• As noted previously, the target MOE for metam-sodium/potassium is 10, and the MOEs
for these key metam use scenarios range from 3 up to 26.
• For the key metam use scenarios presented below, all of the whole field percentiles range
from 60 to 99.9 percent, and the max percentiles range from <5 to 99 percent.
• The use of GAPs, FMPs, and other mitigation measures required by this decision will
contribute to an additional decrease in risk (see GAPs and FMPs sections below, pages
102 and 112 respectively).
Example
Consider the use scenario listed below (in Table 12) for potatoes grown in the Pacific
Northwest using a center pivot with medium release height (i.e., maximum spray height less than
8 feet off the ground and no use of end guns). Here, with an application rate of 140 Ib ai/acre and
an application block size of 120 acres, the buffer zone distance (without emissions credits) would
be 700 feet. Note that:
• The MOE at the 95th air concentration from the PERFUM modeling data at this buffer
distance is 4.
• The risk level corresponding to this buffer zone distance at the 95th percentile whole field
distribution is equivalent to saying a person at any location on the perimeter of the buffer
zone during the worst 24-hour period following the fumigation of a specific field during a 5-
year period would have at least a 75% chance of having of exposure below the level of
concern (i.e., MOE > 10).
• The risk level corresponding to the buffer zone distances at the 95th percentile maximum
distribution is equivalent to saying a person at the location on the perimeter of the buffer
zone where the maximum concentration occurs during the worst case 24-hour period
following the fumigation of a specific field during a 5-year period would have a 15% chance
of exposure below the level of concern (i.e., MOE > 10 for these typical use scenarios).
64
-------
Table 12. Buffer Zone Distances and Risk Characterization for Key Metam Use Scenarios
Crop
Potatoes
Carrots
Cucurbits
Tomatoes
(Processed
)
Tomatoes
(Fresh)
Onions
Peppers
Region
PNW
Upper
Midwest
PNW
CA
WA
AZ&CA
Southeast
CA
Southeast
OR&
WA
CA
CA
Southeast
Application Method
Center Pivot - high release height
Center Pivot - medium release
height without end gun
Center Pivot - low release height
without end gun
Chemigation
Shank Injection
Shank (Broadcast)
Chemigation
Flood
Drip
Center Pivot - high release height
Center Pivot -medium release
height without end gun
Center Pivot - low release height
without end gun
Shank (Strip, Tarped)
Shank (Strip, Tarped)
Shank (Strip, Tarped)
Drip (Tarped)
Shank (Strip, Tarped)
Shank Strip
Shank Strip
Chemigation (Strip)
Drip (Tarped)
Shank (Strip, Tarped)
Typical
Application
Rates
(Ib ai/A)
140
140
140
150
140
170
170
170
170
140
140
140
210
320
40
60
40
60
320
210
110
150
240
240
320
Typical
Application
Block Size
(A)
120-160
120
120
30
50
80
120
80
40
60
40
60
40
60
160
120
120
10
40
10
40
10
40
10
40
10
40
30
40
30
40
10
40
10
40
10
40
Buffer Zone
Distances
(ft) w/o
Credits
900-1300
700
525
200
304
175
225
225
319
463
319
463
107
163
1300
700
525
82
185
200
400
25
38
25
38
200
400
169
185
60
72
250
700
75
150
200
400
Whole Field and
Max Distance
Percentiles
Whole
Field
n/a
75
60
65
65
60
60
65
75
75
65
65
70
65
n/a
75
60
65
60
75
70
97
65
99.9
97
75
70
60
60
65
60
70
80
75
65
75
70
Max
n/a
15
15
<5
<5
<5
<5
<5
15
15
<5
<5
10
<5
n/a
15
15
<5
<5
<5
<5
80
<5
99
80
<5
<5
<5
<5
<5
<5
<5
10
10
<5
<5
<5
MOEs at the
95th Air
Concentration
from
PERFUM2
n/a
4
3
3
3
4
3
3
3
3
3
3
4
4
n/a
4
4
3
3
3
3
15
9
26
11
3
3
3
3
5
3
3
3
5
3
3
3
65
-------
Table 12. Buffer Zone Distances and Risk Characterization for Key Metam Use Scenarios
Peanuts
Sweet
Potato
Tobacco
Eggplant
NC&VA
CA
SC&VA
CA
Southeast
Chisel Strip (Shaped Beds)
Shank (Strip, Tarped)
Shank (Strip Tarped)
Shank (Strip Tarped)
Shank (Strip Tarped)
35
300
90
252
160
320
50
100
10
40
10
40
10
40
10
40
25
75
175
363
25
269
50
75
200
400
Whole Field and
Max Distance
Percentiles
85
75
65
65
85
65
65
60
75
70
35
10
<5
<5
40
<5
<5
<5
<5
<5
12
11
3
3
7
3
4
3
3
3
The Agency believes that the buffer zone distances described above, combined with other
risk mitigation described herein, will provide protection against unreasonable adverse effects.
Amended General Buffer Zone Requirements
The following describes the general buffer zone requirements, as amended, for metam
sodium:
• "Buffer zone" is an area established around the perimeter of each application block or
greenhouse where a soil fumigant is applied. The buffer zone must extend from the edge of
the application block or greenhouse perimeter equally in all directions.
• All non-handlers including field workers, nearby residents, pedestrians, and other bystanders,
must be excluded from the buffer zone during the buffer zone period except for transit (see
exemptions section).
• The "buffer zone period" starts at the moment when any fumigant is delivered/dispensed to
the soil within the application block and lasts for a minimum of 48 hours after the fumigant
has stopped being delivered/dispensed to the soil.
• An "application block" is a field or portion of a field treated with a fumigant in any 24-hour
period. See exception provided in the "Buffer zone proximity" section below.
Buffer zone proximity-Exception to Allow Buffer Zone Overlap
• To reduce the potential for off-site movement from multiple fumigated fields, buffer zones
from multiple metam-sodium and metam-potassium application blocks may not overlap
UNLESS:
o A buffer zone may NOT overlap buffer zones from other application blocks that
are already in effect UNLESS a minimum of 12 hours has elapsed from the time
the first application ends until the second application begins.
For Metam-Sodium and Metam-Potassium Low Release Center Pivot Applications only:
66
-------
o A buffer zone may NOT overlap buffer zones from other application blocks
which are already in effect UNLESS both application blocks are treated using low
release center pivot systems. The 12 hour waiting period does not apply in this
instance.
o Emergency preparedness and response measures specified later in this document
have been implemented if there are any homes, businesses, or property not within
the control of the fumigator within 300 feet of each buffer zone.
Buffer zone distances
• Buffer zone distances must be based on look-up tables on product labels. Twenty-five feet is
the minimum buffer distance regardless of site-specific application parameters.
• For selective replant fumigation in an orchard using hand held application methods (e.g.,
deep injection auger probes), the minimum buffer zone will be 25 feet measured from the
center of each injection site (i.e., tree hole).
Authorized entry to buffer zones
• Only authorized handlers who have been properly trained and equipped according to EPA's
Worker Protection Standard (WPS) and label requirements may be in the buffer zone during
the buffer zone period.
Exemptions for transit through buffer zones
• Vehicular and bicycle traffic on public and private roadways through the buffer zone is
permitted. "Roadway" means that portion of a street or highway improved, designed or
ordinarily used for vehicular travel, exclusive of the sidewalk or shoulder even if such
sidewalk or shoulder is used by persons riding bicycles. In the event a highway includes two
or more separated roadways, the term "roadway" shall refer to any such roadway separately.
(This definition is based on the definition of roadway in the Uniform Vehicle Code prepared
by the National Committee on Uniform Traffic Laws and Ordinances. See
http://www.ncutlo.org/ for more details)
• Bus stops or other locations where persons wait for public transit are not permitted within the
buffer zone.
• See the Posting Section of this document for additional requirements that may apply.
Structures under the control of owner/operator of the application block
• Buffer zones may not include buildings used for storage such as sheds, barns, garages, etc.,
UNLESS,
1. The storage buildings are not occupied during the buffer zone period, and
2. The storage buildings do not share a common wall with an occupied structure.
67
-------
• See the Posting Section of this document for additional requirements that may apply.
Areas not under the control of owner/operator of the application block
• Buffer zones may not include residential areas (including employee housing, private
property, buildings, commercial, industrial, and other areas that people may occupy or
outdoor residential areas, such as lawns, gardens, or play areas) UNLESS,
1. The occupants provide written agreement that they will voluntarily vacate the buffer zone
during the entire buffer zone period, and
2. Reentry by occupants and other non-handlers must not occur until,
0 The buffer zone period has ended, and;
0 Sensory irritation is not experienced
• Buffer zones may not include agricultural areas owned/operated by persons other than the
owner/operator of the application block, UNLESS,
1. The owner/operator of the application block can ensure that the buffer zone will not
overlap with a buffer zone from any adjacent property owners, except as provided for
above, and
2. The owner/operator of the adjacent areas (i.e., areas that are not under the control of the
owner/operator of the application block) provides written agreement to the applicator that
they, their employees, and other persons will stay out of the buffer zone during the entire
buffer zone period.
• Buffer zones must not include roads and rights of way UNLESS,
1. The area is not occupied during the buffer zone period, and
2. Entry by non-handlers is prohibited during the buffer zone period.
3. Applicators must comply with all local laws and regulations.
• For all other publicly owned and/or operated areas such as parks, side walks, walking paths,
playgrounds, and athletic fields, buffer zones must not include these areas UNLESS,
1. The area is not occupied during the buffer zone period,
2. Entry by non-handlers is prohibited during the buffer zone period, and
3. Written permission to include the public area in the buffer zone is granted by the
appropriate state and/or local authorities responsible for management and operation of
the area.
4. Applicators must comply with all local laws and regulations..
Restriction for Schools and Other Difficult-to-Evacuate Sites
• "Difficult-to-evacuate" sites include schools (preschool to grade 12), state licensed day care
centers, nursing homes, assisted living facilities, hospitals, in-patient clinics, and prisons.
• No fumigant application with a buffer zone greater than 300 feet is permitted within 1A mile
(1320 feet) of the sites listed above unless the site is not occupied during the application and
the 36-hour period following the application.
• No fumigant application with a buffer zone of 300 feet or less is permitted within 1/8 mile
(660 feet) of the sites listed above unless the site is not occupied during the application and
the 36-hour period following the application.
68
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(d) Buffer Zone Reduction Credits
Requirements in the July 2008 RED
In preparing for the July 2008 RED, the Agency undertook a significant effort to evaluate
available empirical data results, modeling, and scientific studies reported in the literature
regarding the factors and control methods that may reduce emissions from soil fumigants. For
details on the Agency's analysis, please see the June 9, 2008 memo, "Factors Which Impact Soil
Fumigant Emissions - Evaluation for Use in Soil Fumigant Buffer Zone Credit Factor
Approach,"4 in the metam-sodium and metam-potassium docket. The Agency also coordinated
and led a discussion on this issue at the 2006 and 2007 Methyl Bromide Alternatives Outreach
(MBAO) Conferences with leading researchers and other stakeholders. A general description of
the MBAO sessions can be found at http://mbao.org.
Based on the Agency's analysis of the current data, the Agency developed metam-
sodium and metam-potassium buffer zone reduction credits for: high-barrier tarps (10%), soils
with high organic matter (10%), soils with high clay content (10%), and low-temperature soils
(10%). The July 2008 RED stated that the buffer zone credits were additive, but that the total
credit could not exceed 40 percent. The Agency believes that in addition to reducing bystander
risk and the size of buffer zones, these credits have the potential to also decrease application
rates. Applicators will be required to document any information about buffer zone credits that
apply in the Fumigant Management Plan (FMP).
Comments on the July 2008 RED
Data were submitted since the July 2008 RED was issued that show greater reductions in
emissions from the use of tarps and environmental conditions than what was determined in the
July 2008 RED. In addition, the information submitted during the comment period indicated an
additive effect in reducing emissions when multiple factors were combined. As a result, EPA has
updated the buffer reduction credits and determined that the 40% credit cap should be increased
to 80%. The new credits for individual factors and the cap on credits are detailed below. For
details on the Agency's analysis please see the May 14, 2009 memo; "Methyl Bromide (PC Code
053201), Chloropicrin (PC Code 081501), Dazomet (PC Code 035602), Metam Sodium and
Potassium (PC Codes 039003 & 039002), MITC (PC Code 068103), DP Barcode D362369,
Updated Health Effects Division Recommendations For Good Agricultural Practices and
Associated Buffer Credits", in the metam docket.
Soil Conditions
Soil conditions like the amount of organic matter and type of soil do have an impact on
fumigant emissions. However, soil conditions differ from other credits because they are
4 Factors Which Impact Soil Fumigant Emissions - Evaluation for Use in Soil Fumigant Buffer Zone Credit Factor
Approach, June 9, 2008, DP Barcode: 306857
69
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essentially beyond a grower's ability to change. Although a grower may not be able to
manipulate organic matter or soil type, the Agency's factors document indicates that soil
conditions can reduce fumigant emissions, and is offering credits for these conditions. EPA
acknowledges that some variability in soil characteristics within a given field is likely. If users
are unsure whether the fields they intend to treat meet the criteria for a credit, they may consult
with their local agriculture extension office or soil conservation district for assistance in
determining soil characteristics.
The Agency's factors document not only reviews available literature regarding soil
conditions, but also describes modeling exercises that estimate the impact of organic matter and
soil type using Chain_2D. Chain_2D is a first principles model that takes into consideration
factors such as boundary layers or moisture that could impact fumigant emissions. The Agency
used Chain_2D as modified by Dow AgroSciences' Steve Cryer and Ian van Wesenbeek in the
sensitivity analysis5 Cryer and van Wesenbeek modified the original source code to create a
more usable graphical user interface; this included incorporating a new air/soil boundary
condition proposed by Wang in 19986. See the Agency's factors analysis for further details
about the CHAIN_2D model7.
Based on the review of available literature and modeling with the CHAIN_2D model,
EPA believes 10 percent buffer zone credits are appropriate if the application block contains soil
with organic matter of greater than 3 percent and/or for clay content of at least 27 percent.
CHAIN_2D that shows the impact of changes in organic content is not fumigant specific.
The Agency's Chain_2D sensitivity analysis suggests that organic matter can have a
small impact on emissions. There is generally a high correlation between the organic matter
content of the soils and the dissociation constant (K d) value. Increasing K d value by 10 or 25
percent generally reduced emissions by 10 or 20 percent. Decreasing the Kd value by 10 or 25
percent increased emissions by 10 or 20 percent (see figures 147 to 154 of the factors analysis
for further details).
Generally, clay loam and sandy clay loam soils tended to show significantly lower
emissions than other soil types, sometimes showing 50 percent lower reductions. Conversely,
loamy sand and loam soils tended to show higher emissions than other soil types (see figures 167
to 174 of the factors analysis for further details).
Since the 2008 RED, information from the Chloropicrin Task Force has been submitted
and has allowed the Agency to reevaluate credits for soil organic matter. From these studies the
Agency has determined that soils with between 1% and 2% organic matter will get a 10% credit,
5 Cryer, S.A. (2007) Air/Soil Boundary Conditions For Coupling Soil Physics and Air Dispersion Modeling.
Unpublished report of Dow AgroSciences LLC (Report # DN241493)
6 Wang, D; Yates, S.R.; Jury, W.A. (1998) Temperature Effect on Methyl Bromide Volatilization: Permeability of
Plastic Cover Films. J. Environ. Qual. 27, 821-827.
7 Factors Which Impact Soil Fumigant Emissions - Evaluation for Use in Soil Fumigant Buffer Zone Credit Factor
Approach, June 9, 2008, DP Barcode: 306857
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soils with between 2% and 3% organic matter will get a 20% credit, and greater than 3%, a 30%
credit. No credit will be given for soils with less than 1% organic matter. The credit for clay
content of greater than 27% will remain at 10%.
Soil Temperature
In the July 2008 RED, the Agency provided a 10% buffer zone credit for all chemigation,
center pivot, and/or tractor drawn (i.e., shank injection, spray blade, and rotary tiller) application
in soils with temperatures of 70°F or less when measured at a soil depth of 3 inches for all
chemigation, center pivot, spray blade, and rotary tiller applications and at the injection depth for
shank injection applications. The Agency's analysis of available data indicated increased soil
temperature corresponds to increased fumigant emissions rates. Given that lower soil
temperatures lead to lower fumigant emission rates, a credit was provided for application
scenarios with lower soil temperatures. Because the emissions studies from which the buffer
zones were developed for chemigation, center pivot, and tractor drawn applications all occurred
at high air and soil temperatures, with maximum air temperatures (MATs) between 90-106°F
and/or maximum soil temperatures (MSTs) between 90-93°F (where reported), a credit was
given. Because the emissions studies used to develop buffer distances for the remaining
application methods (i.e., drip and flood irrigation) occurred at lower temperatures, with MATs
between 70-73°F and a MSTs of 70°F (where reported), an emission credit was not provided to
reduce the buffers for these application methods.
During the post-RED comment period, the Agency reviewed all of the currently available
data on the effects of soil temperature on fumigant emissions. Based on this analysis, the Agency
is providing an additional soil temperature credits as described below.
Chemigation, Center Pivot, and/or Tractor Drawn Application
The emissions studies used to currently develop buffer distances for metam sodium
applications performed using chemigation, center pivot, and/or tractor drawn equipment occurred
at high temperatures. The average day/night air temperature in these studies ranged from 80-
90°F and the maximum soil temperatures ranged from 90-93°F (where reported). A 10%
emission credit is being provided to reduce the buffers for these types of applications in soils
with temperatures ranging from 50-70°F when measured at a soil depth of 3 inches. In addition
a 20% emission credit is being provided to reduce the buffers for these types of applications in
soils with temperatures of 50°F or less when measured at a soil depth of 3 inches.
Drip and Flood Application
The emissions studies used to currently develop buffer distances for metam sodium
applications performed using drip and flood irrigation equipment occurred at reasonable
temperatures. The average day/night air temperature in these studies was approximately 60°F
and the maximum soil temperatures around 70°F (where reported). A 10% emission credit is
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being provided to reduce the buffers for these types of applications in soils with temperatures of
50°F or less when measured at a soil depth of 3 inches.
Note: Stakeholders and the registrants have proposed a laboratory soil column study examining
the effect of soil temperature and soil moisture on MITC emissions. This study may provide
more information around the effect on MITC emissions and the emissions for metam-sodium and
metam-potassium may be revisited if necessary after review of these data.
High-Barrier Tarps
In the July 2008 RED, a 10% buffer credit was given when one of the following high-
barrier tarps is used: Bromostop® (1.38 mil), IPM Clear VIF (1.38 mil), Eval/Mitsui (1.38 mil),
Hytiblock 7 Black (0.00125"), XL Black Blockade (0.00125"), or Hytibar (1.5 mil) for either a
shank injection or drip metam-sodium and metam-potassium application. Because current study
data do not demonstrate significant reductions in MITC emissions using standard polyethelyne
tarps, no credit was provided for "standard" tarped metam applications. The credit was based on
a study (Papiernik 2004) that shows significant reductions in MITC emissions when using a
Hytibar (a high-barrier) tarp when compared to a standard polyethylene tarp in drip irrigation
experiments in both sand mesocosm and field experiments. Given that study data (Wang et al.,
2006) have shown that MITC and chloropicrin pass through standard tarps at similar rates, the
Agency decided to allow emissions credits for the Hytibar tarp as well as the other high-barrier
tarps that were given an emissions reduction credit for chloropicrin applications. The Agency
believed that the actual reduction for tarps could be higher for certain conditions but that a 10%
credit was appropriate based on uncertainties in the available data.
Since the July 2008 RED was published, the Agency has looked at all of the available
tarp data, in total. There is very limited data currently available that examines the ability of high-
barrier tarps to reduce MITC emissions. One literature study (Papiernik et. al., 2004) showed
significant reductions in MITC emissions when using a Hytibar (a high-barrier) tarp when
compared to a standard polyethylene tarp in drip irrigation experiments. Also, another study
(Wang et. al., 2006) showed that MITC and chloropicrin pass through standard tarps at similar
rates (same order of magnitude).
As a result, the Agency has decided to allow emissions credits for all high-barrier tarps
that are being given an emissions reduction credit for chloropicrin. The Agency has selected
more conservative credits for MITC based on uncertainties in the available data.
• A 15% buffer credit is appropriate for the following high-barrier tarps: Canslit
Heatstrip Silver and Canslit Metalized.
• A 30% buffer credit is appropriate for the following high-barrier tarps: Olefinas
Embossed VIF, Klerks VIF, Pliant Blockade, Bromostop® (1.38 mil),
Eval/Mitsui TIF (1.38 mil), Hytiblock 7 Black (0.00125"), XL Black Blockade
(0.00125"), Hytibar (1.5 mil), and IPM Clear VIF (1.38 mil).
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Credit Cap
The Agency determined, in the July 2008 RED, that the buffer zone credits were
additive. This meant, for example, that a 10% credit for a high barrier tarp could be added to a
10 % credit for organic matter to achieve a total credit of 20%. The Agency placed a limit, or
"credit cap," of 40% on the total size of the credit allowed for metam. During the comment
period, the Agency received new data concerning a number of factors that impact fumigant
emissions as well as a number of comments indicating that there should not be a cap on credits or
that the cap should be raised. Some suggested that the 40% cap would be a disincentive to
growers considering whether to adopt emission-reducing application methods.
Upon review of the new data and public comments, the Agency has decided to raise the
credits cap to 80%. The Agency has reviewed the new studies to evaluate the extent to which the
various factors that reduce emissions act independently, and has reconsidered the earlier studies.
As a result of this evaluation, the Agency concludes that credits be additive up to a cap of 80%
for all fumigants. This revised credit cap is based on studies that show a greater-than-40%
reduction in emissions when two or more factors are combined. Further, EPA believes that
increasing the credit cap to 80% will encourage adoption of emission reduction techniques, result
in lower off-site fumigant concentrations, and will allow for reduced application rates for various
tarps.
Credit Example
If an application block is 10 acres and the applicator is planning to make a shank tarped
application of 320 Ibs of metam per acre, the buffer distance from the look up tables is 200 feet.
If the applicator decides to use the Hytibar (1.5 mil) high barrier tarp, then the buffer zone may
be reduced by 30 percent. By calculating 30 percent of 200 feet (200 feet x 30% = 60 feet buffer
credit) and then subtracting the original buffer distance by the credit (200 feet - 60 feet =140
feet) the final buffer distance required is 140 feet.
Other Buffer Zone Credits Considered
Other factors such as soil moisture content, field preparation, water sealing, and
application injection depth could not be quantified as to how effectively they reduce emissions
and were not used to establish buffer credits at this time. However, EPA has established
mandatory good agricultural practices (GAPs) for these conditions. If additional tarps or other
emission factor data become available to show the emissions from metam-sodium and metam-
potassium applications are decreased, the Agency will consider adding those to the metam-
sodium and metam-potassium label. More information on the type of data the Agency is looking
for can be found in the Health Effects Division Recommendations for Fumigant Data
Requirements (J. Dawson, C. Smith, dated June 2008).
EPA (through OPP's Environmental Stewardship Branch) has proposed to co-fund a
grant with USDA-ARS for several flux studies in the southeastern U.S. These studies would
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provide (1) field data on the emission reduction potential of certain low permeability barrier
films to support possible, additional, buffer reduction credits as well as to (2) help develop an
affordable and reliable hybrid field/lab test to evaluate the many barrier films available to
growers. EPA has also prepared a document to describe possible research and study designs to
reduce uncertainties in understanding emission factors in the context of different films and seals,
agricultural practices, and environmental conditions.8 These studies were completed in the
spring of 2009 and data from these studies will be submitted to the Agency for review in the near
future.
Other factors such as soil moisture content, field preparation, water sealing, and
application depth could not be used to justify credits based on the available data. However, EPA
has established mandatory good agricultural practices (GAPs) for these conditions. See the GAP
section of this document for further discussion. If additional data on such emission reduction
methods becomes available, EPA will consider developing further credits.
2. Restriction for Schools and Other Difficult To Evacuate Sites
Certain types of sites are difficult to evacuate should an incident occur. EPA determined
that additional measures to reduce the potential need to evacuate these types of sites were
necessary to reduce risk of exposure to occupants and address potential challenges associated
with an accident. There were many comments on this measure including: requests to delete this
requirement; suggestions to reduce the size of the restricted area; a proposal to use a scalable
approach to calculate the distance; requests to define and refine the places included on this list so
that facilities such as research universities were excluded; suggestions to shorten the duration of
the requirement so applicators may be able to take advantage of weekends to fumigate; questions
about how to determine where these sites are located, and other suggestions to change the
required measures.
Based on a review of the comments, the Agency has retained this mitigation measure to
ensure the protection goals are still achieved and encourage lower-emission application methods.
The mitigation measures have been refined such that compliance is more effective in achieving
the protection goal. Modifications to this requirement include: shortening the duration of the
restriction so weekends may be used to fumigate near schools and day cares; clarifying the types
of schools that are covered by this requirement; removing the term "elder care facilities" from
the list since many of the same facilities are included in the terms, " assisted living facilities,
nursing homes, and in-patient clinics;" and reducing the restricted area from 1/4 mile to 1/8 mile
for application blocks with less than 300 foot buffers. The 1/8 mile (660 feet) distance is more
than twice the required buffer distance and remains protective of people who may be difficult to
evacuate while reducing the potential challenges of complying with the restrictions for some
users who may be fumigating in close proximity to these types of institutions. EPA has
determined that these modifications achieve the same protection goals as the 2008 RED but
provide additional clarity and flexibility that will enhance users' ability to practically and
effectively comply with the requirements. EPA also believes that reducing the restricted area for
' Health Effects Division Recommendations for Fumigant Data Requirements. June 2008. DP Barcode 353724
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blocks with buffers less than 300 feet will provide an incentive for some users to adopt lower-
emission application methods or practices. The revised measures are summarized below.
• "Difficult-to-evacuate" sites include schools (preschool to grade 12), state licensed day
care centers, nursing homes, assisted living facilities, hospitals, in-patient clinics, and
prisons.
• No fumigant application with a buffer zone greater than 300 feet is permitted within 1/4
mile (1320 feet) of the sites listed above unless the site is not occupied during the
application and the 36-hour period following the start of application.
• No fumigant application with a buffer zone of 300 feet or less is permitted within 1/8
mile (660 feet) of the sites listed above unless the site is not occupied during the
application and the 36-hour period following the start of application.
3. Posting
Posting is recognized as an effective means of informing workers and bystanders about
areas where certain hazards and restrictions exist. Current soil fumigant labels require treated
areas to be posted and handlers are required to wear specific PPE when they are in a treated area.
For buffer zones to be effective risk mitigation, bystanders, including agricultural workers in
nearby areas, need to be informed of the location and timing of the buffer zone to ensure they do
not enter designated areas.
In addition to alerting bystanders, posting a buffer zone will help handlers determine
where and when they are required to use PPE. As described in the Handler Section, handlers
working in treated areas or buffers during the buffer zone period must use label-specified PPE
and meet other requirements under the Worker Protection Standard (WPS). Therefore, EPA has
determined that to ensure the protectiveness of buffers for bystanders and handlers, the perimeter
of the fumigant buffer zones must be posted.
Comments received in response to the July 2008 RED decisions recommended some
changes to the posting requirements to make them easier to understand and implement. Based on
EPA's review and consideration of these comments, EPA has slightly revised the posting
requirements and provided additional clarification as described below.
EPA had included two exceptions for the buffer zone posting requirement. The first
exception did not require posting in situations where the land 300 feet from the edge of the
buffer was under the control of the property operator. Based on comments that this measure was
too complicated and confusing this exception has been removed. There were also comments that
the examples provided in the description of a physical barrier may lead to misinterpretation of
the requirement. EPA agrees and believes that a performance standard is a more effective means
of communicating the requirement. Therefore, to reduce the potential for confusion, the
examples have been removed.
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In the 2008 RED, signs were required to be posted at usual points of entry and likely
routes of approach to buffer zones. If there were no usual points of entry or likely routes of
approach, then posting was required in the corners of buffer zones, and between the corners, so
signs could be viewed from one another. Many comments expressed concern over the burden
and potential confusion with the number of signs that may need to be posted and how many signs
may need to be posted depending on the configuration of the field. EPA agrees that signs posted
in areas where there is low likelihood of workers or others approaching or accessing the buffer
provide little risk reduction, but can add substantially to the challenges of compliance. As a
result, the Agency has revised the criteria for location of signs since the areas that are of most
concern are those where people are most likely to enter (e.g., roads, footpaths, etc.), and at likely
routes of approach such as the perimeter of a buffer that faces a housing development.
Comments also indicated that the requirement to include certain application-specific
information on the posted signs would make reuse of the signs more difficult and would also
substantially increase the amount of time needed to prepare signs before posting. These
comments stated that the primary purpose of signs is to communicate to bystanders the buffer
zone locations. EPA generally agrees with these comments; therefore certain application-
specific details on the posted signs, like the date and time of the fumigation and buffer zone
restrictions, have also been reduced to allow the signs to be reused more easily.
Comments also stated that the posting example included in the 2008 RED was confusing.
Since the posting restrictions have been simplified by removing the distance criteria, the example
has been removed from this document. There were no substantive comments suggesting a
change to the exception for posting multiple contiguous blocks and no changes have been made
in this Amendment.
The revised posting requirements are listed below and have been included in the revised
label table.
Requirements
• Posting of a buffer zone is required unless there is a physical barrier that prevents
bystander access to the buffer zone.
• Buffer zone posting signs must:
o Be placed at all usual points of entry and along likely routes of approach from areas
where people not under the land operator's control may approach the buffer zone.
o Some examples of points of entry include, but are not limited to, roadways,
sidewalks, paths, and bike trails.
o Some examples of likely routes of approach are the area between a buffer zone and a
roadway, or the area between a buffer zone and a housing development.
• Buffer zone posted signs must meet the following criteria:
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o The printed side of the sign must face away from the treated area toward areas from
which people could approach.
o Signs must remain legible during entire posting period and must meet the general
standards outlined in the WPS for text size and legibility (see 40 CFR §170.120).
o Signs must be posted before the application begins and remain posted until the buffer
zone period has expired.
o Signs must be removed within 3 days after the end of the buffer zone period.
o Registrants must provide generic buffer zone posting signs which meet the criteria
above at points of sale for applicators to use.
Exception: If multiple contiguous blocks are fumigated within a 14-day period, the entire
periphery of the contiguous blocks' buffer zones may be posted. The signs must remain posted
until the last buffer zone period expires and signs may remain posted until 3-days after the buffer
zone period for the last block has expired.
Additional requirements for treated-area posting:
• The treated area posted signs must remain posted for no less than the duration of the entry
restricted period after treatment.
• Treated area signs must be removed within 3 days after the end of the entry-restricted
period.
• Signs must meet the general standards in the WPS for placement, text size, and location
(40 CFR §170.120).
Contents of Signs
The treated area sign (currently required for
fumigants) must state the following:
~ Skull and crossbones symbol
The buffer zone sign must include the
following:
— Do not walk sign
- "DANGER/PELIGRO,"
~ "Area under fumigation, DO NOT
ENTER/NO ENTRE,"
~ "Metam-sodium [or metam-potassium]
Fumigant in USE,"
~ the date and time of fumigation,
~ the date and time entry prohibition is lifted
~ Name of this product, and
~ name, address, and telephone number of the
certified applicator in charge of the fumigation.
- "DO NOT ENTER/NO ENTRE,"
~ "Metam-sodium [or metam-potassium]
[Name of product] Fumigant BUFFER
ZONE,"
~ contact information for the certified
applicator in charge of the fumigation
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bb. Occupational Risk Mitigation for Soil Uses
The Agency has concerns for handlers involved in metam-sodium and metam-potassium
applications for both dermal and inhalation exposure. In many cases with maximum personal
protective equipment (PPE), exposure still exceeds the Agency's level of concern for short-term
and long-term exposures. Based on stakeholder comments, there appears to be a
misunderstanding as to what EPA considers to be handler activities.
1. Handler Definition
Based on stakeholder comments provided during the Phase 5 comment period, the July
2008 RED clarified fumigation tasks that meet EPA's definition of handler activities, as
currently defined in the WPS and on fumigant labels. During the post-RED comment period the
Agency received some comments from stakeholders who were concerned that the Agency was
redefining handlers. It was not the Agency's intention to change the current definition. As a
result, the Agency has slightly changed the language from July 2008 RED so it is clear that the
Agency is just clarifying the existing definition and not writing a new one. Below is the revised
language.
"The following activities are prohibited from being performed in the fumigant application
block or surrounding buffer zone during the buffer zone period by anyone other than persons
who have been appropriately trained and equipped as handlers in accordance with the
requirements in the Worker Protection Standard (40 CFR Part 170), from the start of the
application until the entry-restricted period ends. Those activities include those persons:
• Participating in the application as supervisors, loaders, drivers, tractor co-pilots,
shovelers, cross ditchers, or as other direct application participants (note: the application
starts when the fumigant is first introduced into the soil and ends after the fumigant has
stopped being delivered/dispensed to the soil);
• Using devices to take air samples to monitor fumigant air concentrations;
• Persons cleaning up fumigant spills (this does not include emergency personnel not
associated with the fumigation application);
• Handling or disposing of fumigant containers;
• Cleaning, handling, adjusting, or repairing the parts of fumigation equipment that may
contain fumigant residues;
• Installing, repairing, or operating irrigation equipment in the fumigant application block
or surrounding buffer zone during the buffer zone period;
• Entering the application site or surrounding buffer zone during the buffer zone period to
perform scouting or crop advising tasks;
• Installing, perforating (cutting, punching, slicing, poking), removing, repairing, or
monitoring tarps:
o until 14 days after application is complete if tarps are not perforated and removed
during those 14 days, or
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o until tarp removal is complete if tarps are both perforated and removed less than
14 days after application; or
o until 48 hours after tarp perforation is complete if they will not be removed within
14 days after application.
o In addition, to the above, persons outside the perimeter of the buffer zone who visually
monitor application equipment to ensure proper functioning and monitor fumigant air
concentrations must also be trained and equipped as handlers in accordance with the
requirements in the WPS (40 CFR Part 170)."
2. Handler Requirements
Since many incidents are caused by human error and equipment failure, EPA believes the
presence of on-site trained personnel would help to reduce these risks. To address these risks,
the July 2008 RED required that (1) a certified applicator must supervise all fumigant handlers
during the entire period that the person is performing a fumigant handling task within the treated
field or within the buffer zone, (2) the person monitoring another handler could also be engaged
in fumigant handling tasks during the monitoring period, and (3) the certified applicator
supervising metam-sodium and metam-potassium applications could perform all tasks without
anyone supervising them.
The July 2008 Metam-Sodium and Metam-Potassium RED included exceptions for the
on-site applicator supervision requirements in cases when the certified applicator typically leaves
the site during an application. Requirements in the RED label table specified that for overhead,
flood, or furrow irrigation and chemigation applications, the certified applicator supervising the
fumigant application must be on site at the start of application but may leave and return for
periodic monitoring of the fumigation site as long as he/she monitors the site at least once every
four hours if the site is 20 acres or less; once every three hours if the site is greater than 20 acres,
but less than 80 acres; and once every two hours if the site is 80 acres or more. The Agency
believes that consistent monitoring of water-run applications (e.g., drip, overhead, flood, or
furrow irrigation and chemigation) is needed to help reduce potential risks during an application.
In addition to certified applicator supervision, in the July 2008 RED, the Agency required
that a minimum of two WPS-trained handlers remain on site when handlers are fixing tarps,
moving irrigation equipment, and/or performing other handler tasks as defined above. This
mitigation measure was put in place to address the possibility that handlers could be overcome
with the vapors and have difficulty leaving the area while they are performing these tasks. The
Agency is removing this handler requirement for the MITC generating chemicals since the
hazard profiles are not the same for all the soil fumigants. With MITC-generating compounds,
EPA believes eye or sensory irritation would likely be felt in sufficient time for a handler to
leave the area or put on a respirator, before more serious effects occur. With chloropicrin, in
contrast, as indicated by precautionary statements on current labels, a handler may be overcome
more quickly, justifying the presence of another person to provide assistance if needed.
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During the post-RED comment period the Agency received many comments that stressed
the difficulty implementing a requirement that mandates certified applicators to maintain visual
contact with handlers. The commenters also indicated that for longer applications this
requirement would be a huge burden. Other stakeholders stated that the Agency needs to modify
the requirement to ensure that the certified applicator is on site while others believe EPA should
require that all handlers are certified applicators, which would eliminate the need for direct
handler supervision.
The Agency has considered the comments and has revised the certified applicator and
WPS-trained handler requirements for different application methods. EPA believes that these
revisions accomplish the same goal as the July 2008 RED mitigation while reducing the burden
on users.
• For all applications, except water run, (e.g., shank, rotary tiller, etc.) from the start of the
application until the fumigant has stopped being delivered/dispensed into the soil, i.e.,
after the soil is sealed, the certified applicator must be at the fumigation site and must
directly supervise all persons performing handling activities.
• For water-run applications (e.g., chemigation, center pivot, lateral move, drip, overhead,
flood, furrow irrigation, etc.), the certified applicator must be at the fumigation site to
start the application including set-up, calibration, and initiation of the application. The
certified applicator may leave the site but must return at least every two hours to visually
inspect the equipment to ensure proper functioning and monitor the air around the buffer
zone and must supervise all WPS-trained handlers on-site until the fumigation has
stopped being delivered/dispersed into the soil. WPS-trained handlers may perform the
monitoring functions in place of the certified applicator but must be under the supervision
of the certified applicator and able to communicate with the certified applicator at all
times during monitoring activities via cell phone or other means. The results of
monitoring activities must be captured in the FMP.
• For fumigant handling activities that take place after the fumigant has been
delivered/dispensed into the soil until the entry restricted period expires, the certified
applicator does not have to be on-site, but must have communicated in writing to the site
owner/operator and handlers the information necessary to comply with the label and
procedures described in the FMP (e.g., emergency response plans and procedures).
The July 2008 RED also required that certified applicators supervising the application
completed a metam-sodium and metam-potassium registrant training program within the
preceding 12 months before they applied a metam-sodium and metam-potassium product. The
Agency is still requiring certified applicators complete the registrant training; however, the
Agency is now requiring the certified applicators successfully complete the training every three
years. Please see the Soil Fumigation Training for Applicators and Other Handlers section for
further.
3. Dermal Protection for Handlers
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The Agency's human health risk assessment for metam-sodium and metam-potassium
identifies dermal risks for many handler tasks that exceed the Agency's level of concern for
short-term, and intermediate-term exposures to the parent metam-sodium and metam-potassium.
To address these dermal risk concerns, in the July 2008 Metam-Sodium and Metam-Potassium
RED, the Agency required handlers engaged in various tasks (e.g., transferring or loading
liquids; operating motorized ground application equipment with open cabs; and cleaning up
spills) to wear dermal protection (e.g., double layer clothing, chemical resistant footwear plus
socks) to protect against dermal exposure.
During the post-RED comment period, the Agency received a comment from the
Northwest Horticultural Council indicating that the primary application method for orchard
replant using metam sodium in the Pacific Northwest, a row/strip treatment of metam sodium to
a future tree row using a weed sprayer while irrigation sprinklers are running, was not
specifically addressed in the Agency's RED decision. Based on additional information provided
by a representative for the Council in a 3/13/08 e-mail to the Agency (a copy of this e-mail has
been posted to the metam sodium docket at EPA-HQ-OPP-2005-0125), EPA is including this
application method, provided that handlers wear the following dermal PPE to protect them from
both the product and sprinkler irrigation: long-sleeved shirt and long pants; a full waterproof,
chemical-resistant suit; chemical-resistant gloves; chemical-resistant footwear plus socks; and
protective eyewear. Generally, the Agency does not like to require the use of full waterproof,
chemical-resistant suits for handlers, given concerns regarding heat stress for handlers, especially
for handheld applications. However, based on the comments submitted by the Council indicating
that this PPE is currently a standard practice and these applications are likely occurring in a
cooler weather climate, the Agency is requiring such PPE in this instance.
The majority of comments relating to dermal handler protection for metam-sodium and
metam-potassium that the Agency received during the post-RED comment period involved the
need for additional clarification of key dermal handler mitigation and risk concerns. Specifically,
clarification of the "baseline work clothes" requirement was requested. The Agency has more
clearly defined this term in the dermal requirements section below to avoid any potential
confusion.
Additionally, during the post-RED comment period, the Agency received comments from
various stakeholders indicating that the Agency had not fully characterized the dermal risks from
metam-sodium and metam-potassium, specifically short-term and intermediate-term non-cancer
and cancer dermal risks in the July 2008 Metam-Sodium and Metam-Potassium RED. To address
these concerns, the Agency is providing additional characterization of these risks below.
Metam-Sodium and Metam-Potassium Non-Cancer Occupational Dermal Risks: Short-Term
and Intermediate-Term
The results of the non-cancer, short-term and intermediate-term handler dermal exposure
assessments indicate that the MOEs for the dermal risk to handlers with both full PPE (i.e.,
gloves and double-layer clothing) and/or engineering controls (i.e., closed mixing and loading
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systems and use of enclosed cabs) are above the Agency's level of concern (LOG) (i.e., MOE <
100) for many of the agricultural scenarios. The estimated exposures and risks are summarized in
Tables 1-4 in Appendix J of the third revision of the Agency's human health risk assessment. To
view, please see, "Metam Sodium: Third Revision of the HED Human Health Risk Assessment,
DP# 293354 located in the metam sodium docket at: EPA-HQ-OPP-2005-0125.
For short-term hander exposure scenarios, the margins of exposure (MOEs) for handlers
loading metam products at higher application rates for large acreage applications exceed the
Agency's level of concern even with the addition of maximum personal protective equipment
(PPE). This is also true for applicators who are applying metam products at higher application
rates for large acreage applications. However, for many of the short-term handler exposure
scenarios, when loading metam products for more typical acreage applications at typical
application rates, MOEs are below the Agency's level of concern when additional PPE and/or
engineering controls are incorporated. For applicators, when treating typical acreage at more
typical application rates, MOEs are below the Agency's level of concern with additional PPE or
when using a closed cab that provides dermal protection.
For intermediate-term exposures, the MOEs for handlers for the dermal risk to handlers
with both full PPE (e.g., gloves and double-layer clothing) and/or engineering controls (e.g.,
closed mixing and loading systems) exceed the Agency's LOG (i.e., MOE < 100) for the
majority of the agricultural scenarios.
Short- and intermediate-term dermal exposure MOEs for many handler scenarios are
below an MOE of 100 with the required dermal protection and/or engineering controls. The
occupational dermal risk assessments are based on data from the Pesticide Handler Exposure
Database (PHED) and Outdoor Residential Exposure Task Force (ORETF). PHED and ORETF
were designed to be used to assess nonvolatile pesticides. In the case of metam-sodium and
metam-potassium, these data were used because there are no chemical-specific data available to
the Agency. Since metam-sodium and metam-potassium degrades quickly to MITC, the dermal
short- and intermediate-term risk assessment for metam generated by the Agency using data
from PHED and ORETF can be considered to be conservative.
For the intermediate-term dermal exposures, another source of conservatism comes from
the assumption that workers are exposed throughout an 8-hour workday for a 1- 6 month period.
However, the Agency believes that many handlers, particularly private applicators of metam
sodium, typically apply metam-sodium and metam-potassium for much shorter periods of time.
In a 2004 survey of growers and applicators that use metam sodium conducted by the Metam
Sodium Alliance and reviewed by the Agency, average number of days per year that growers
reported potential metam exposure was 15 days, while custom applicators had an average of 50
days per year.
To address the short- and intermediate-term dermal risks from metam-sodium and
metam-potassium, consistent with the mitigation required in the July 2008 RED, the Agency is
requiring handlers engaged in various tasks to wear dermal protection to protect against dermal
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exposure. Given the conservative nature of the non-cancer short- and intermediate-term dermal
exposure assessment, coupled with the Agency's dermal PPE requirements and engineering
control requirements, which are detailed below in the dermal requirements section, the Agency
believes that these measures are protective of possible short-term and intermediate-term dermal
risks for metam-sodium and metam-potassium.
Metam-Sodium andMetam-Potassium Cancer Occupational Risks: Dermal Exposures
The Agency's metam-sodium and metam-potassium cancer occupational handler dermal
exposure assessment indicates that cancer risks for both noncommercial and commercial
handlers are above the Agency's LOG (ranging from IxlO"4 to IxlO"6) for the majority of
agricultural scenarios with maximum PPE in place. This assessment should be considered
conservative for a number of reasons. (1) The assessments were based on data from PHED and
ORETF, which are generally meant to assess non-volatile pesticides. Using this data to assess
dermal exposure to metam sodium should be considered very conservative due to the volatile
nature of metam sodium. (2) Closed systems are used to mix and load metam-sodium and
metam-potassium, which will greatly reduce any potential exposure to metam-sodium and
metam-potassium itself. (3) Much of the equipment typically used to apply metam-sodium and
metam-potassium also greatly reduces any potential exposure to metam-sodium and metam-
potassium itself. Tractor applications of metam sodium either immediately incorporate or
directly inject metam sodium into the ground, and handlers are typically not in the field during
chemigation applications.
Dermal Requirements
The Agency is requiring the mitigation measures specified below to reduce dermal
exposures for handlers. Where indicated, "baseline work clothes" refers to long-sleeved shirt,
long pants, and socks and shoes.
• Transferring Liquids
o To reduce risk to handlers who transfer liquids from any container into
application equipment or delivery equipment, the following is required:
• Double-layer clothing (i.e., baseline work clothes and coveralls),
chemical-resistant gloves, chemical-resistant apron, chemical-resistant
footwear plus socks, and protective eyewear.
o To reduce risk to handlers who transfer liquids from any container into
application equipment or delivery equipment using a closed-connect system that
reduces leakage to less than 2 ml of liquid per disconnect, the following is
required:
• Baseline work clothes, chemical resistant gloves, chemical resistant apron,
protective eyewear, and a closed-connect system.
• Driving Ground Rigs:
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o To reduce risk to handlers driving ground rig with a closed cab that provides
dermal protection, the following is required:
• Baseline work clothes.
o To reduce risk to handlers driving a ground rig that does not provide dermal
protection, the following is required:
• Double-layer clothing (i.e., baseline work clothes and coveralls) and
chemical-resistant footwear plus socks.
• Set-up, Calibration, and Start Up of Chemigation Equipment:
o To reduce risk to handlers who set-up and calibrate chemigation and irrigation
equipment and either start the application from inside the buffer zone or remotely
start the application from outside the buffer zone, the following is required:
• Baseline work clothes.
• Row'/Strip Treatment Application of Me tarn Sodium via Weed Sprayer while Irrigation
Sprinklers are Running:
o To reduce risk to handlers who apply metam-sodium and metam-potassium via
weed sprayer while irrigation sprinklers are running for row/strip treatment for
orchard replant, the following is required:
• Long-sleeved shirt and long pants; chemical-resistant gloves; a full
waterproof, chemical-resistant suit and chemical-resistant footwear plus
socks; and protective eyewear.
• Early Entry or Monitoring PPE:
o To reduce risk to handlers (1) entering a treated area during the application or (2)
entering the treated field up to 120 hours after the application has ended for any
reason (including, but not limited to, equipment repair, cleaning up spills,
equipment monitoring, scouting), or (3) entering the buffer zone for up to 48
hours after the application, the following is required:
• Baseline work clothes. If the handler will to be exposed to liquid or liquid
spray from the application equipment, they must wear chemical-resistant
coveralls, chemical-resistant gloves, chemical- resistant apron, chemical
resistant footwear plus socks, and protective eyewear.
4. Respiratory Protection for Handlers
The Agency's human health risk assessment for metam indicates that inhalation risks for
many handler tasks exceed the Agency's LOG for the acute exposure to the parent (metam) and
MITC. In the 2008 Metam-Sodium and Metam-Potassium RED, the Agency required handlers
potentially exposed to MITC vapors from metam-sodium and metam-potassium applications to
either wear at least a half-face respirator during the handling activity, or follow the monitoring
program detailed below. In addition, the Agency required that for some handling tasks,
respirators were required to be worn at all times due to the short duration of the task and the
potentially high concentration of MITC exposure. The certified applicator supervising the
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fumigant application must ensure that any handler who enters the buffer zone (including tractor
drivers, loaders, irrigators, tarp cutters, removers, etc.) is either wearing respiratory protection or
is following the handler monitoring requirements, with respirators immediately available to each
handler.
During the post-RED comment period, the Agency received several comments on the
Respiratory Protection for Handlers section. For MITC, comments focused on the feasibility of
using colormetric tubes, due to the current sensitivity and accuracy of the tubes; the cost of the
tubes; and the Agency's trigger level of 100 ppb, which some commenters questioned, given that
the Agency's level of concern for acute MITC exposures is 22 ppb. Some comments also
suggested that rather than wear respirators, fumigators should have the option of ceasing the
application until air concentrations of MITC are less than the action level.
After reviewing the comments, the Agency has determined that respiratory protection is
still needed to mitigate risks to metam-sodium and metam-potassium handlers if concentrations
of MITC reach a certain level; however, EPA is revising the required procedures for determining
when respirators must be used due to technological limitations of currently available monitoring
devices that are appropriate for field use. EPA believes that while colorimetric tubes are likely
to be reliable at higher concentrations and when used in more static conditions (e.g., a warehouse
or laboratory), under the dynamic conditions characteristic of outdoor field fumigation, currently
available devices provide somewhat less reliable information about concentrations relative to
EPA's action level, which is below the levels for which the devices are rated.
The Agency is aware of several commercial systems for monitoring MITC, including
colormetric tubes from the following manufacturers: Sensidyne and Dragaer. While these tubes
have detection limits of at least 100 ppb, based on commenters' experience and the accuracy of
the tubes (e.g., some tubes have a standard deviation plus or minus 20-30%), the Agency
believes it is possible that handlers will experience sensory irritation before the monitoring
device shows a level of concern. As such, the Agency does not believe that initial monitoring to
trigger the use of respirators significantly reduces handler risks. EPA is also concerned that
monitoring with devices that are not reliable could cause handlers to believe that concentrations
are below the action level despite other indications (eye irritation). As a result, the Agency is
removing the initial monitoring requirement. In addition, EPA is aware that monitoring with
these devices adds significant costs to fumigations. For additional details please see the
following document: Analysis of Soil Fumigant Risk Management Requirements using
Geographic Information Systems: Case Studies based on a Forest Seedling Nursery, dated May
13, 2009, located in the metam docket.
EPA does believe, however, that monitoring devices that are currently available will
generally be reliable at higher concentrations of MITC and that there is high value in air
monitoring using currently available devices in certain situations. As a result, EPA is
maintaining the requirement for colorimetric tube monitoring once use of respirators has been
triggered and respirators are being worn. This will enable handlers to detect concentrations that
would exceed the upper working limit of the respirator. Additionally monitoring will still be
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required to help enable handlers to determine if concentrations have decreased and whether it is
safe to either remove respirators or to resume the application if the fumigator has opted to cease
the application rather than wear respirators.
The Agency is modifying the procedures for respiratory protection because of
technological limitations of currently available devices. However, the Agency does believe that
quantitative air monitoring would enhance worker safety if the appropriate technology were
available. Some equipment manufacturers have indicated interest in developing devices that
would be more functional and reliable for field fumigation applications (e.g., badge-type
monitors). EPA encourages such efforts and plans to stay abreast of developments and
improvements in monitoring devices and will consider this issue again in registration review or
sooner should such monitors become available in the short term.
Since the Agency has removed the initial monitoring requirement, regulating at an action
level of 100 ppb is no longer appropriate since that level was based on the lowest detection limit
of the currently available MITC monitoring tubes. Due to the reliability issue discussed above,
instead, the Agency is using an action level of 600 ppb which corresponds to early signs of
exposure and effects are non-severe and reversible at this level. The Agency believes that this
level is effective as a warning for handlers of when concentrations are reaching the point where
steps are needed to protect fumigant handlers from inhalation exposures.
Respiratory Requirements
The following procedures must be followed for all agricultural pre-plant soil applications
of metam-sodium and metam-potassium. In addition to the respiratory protection requirements,
the Agency believes that GAPs, FMPs, and other mitigation measures will reduce inhalation
risks from MITC to levels below the EPA's level of concern.
• If at any time any handler experiences sensory irritation (tearing, burning of the eyes or
nose) then either:
o An air-purifying respirator (APR) must be worn by all handlers who remain in the
application block and surrounding buffer zone, or
o Operations must cease and handlers not wearing respiratory protection must leave
the application block and surrounding buffer zone.
• Handlers can remove respirators or resume operations if two consecutive breathing-zone
samples taken at the handling site at least 15 minutes apart show that levels of MITC
have decreased to less than 600 ppb, provided that handlers do not experience sensory
irritation. Samples must be taken where the irritation is first experienced.
• When respirators are worn, then air monitoring samples must be collected at least every 2
hours in the breathing zone of a handler performing a representative handling task.
• If at any time: (1) a handler experiences any sensory irritation when wearing a respirator,
or (2) an air sample is greater than or equal to 6000 ppb, then all handler activities must
cease and handlers must be removed from the application block and surrounding buffer
zone. If operations cease the emergency plan detailed in the FMP must be implemented.
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Handlers can resume work activities without respiratory protection if two consecutive
breathing-zone samples taken at the handling site at least 15 minutes apart show levels of
MITC have decreased to less than 600 ppb, provided that handlers do not experience
sensory irritation.
During the collection of air samples an air-purifying respirator must be worn by the
handler taking the air samples. Samples must be taken where the irritation is first
experienced.
Work activities may resume if the following conditions exist provided that the
appropriate respiratory protection is worn:
o Two consecutive breathing zone samples for MITC taken at the handling site at
least 15 minutes apart must be less than 600 ppb,
o Handlers do not experience sensory irritation while wearing the APR, and
o Cartridges have been changed.
o During the collection of air samples an air-purifying respirator must be worn by
the handler taking the air samples. Samples must be taken where the irritation is
first experienced.
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Figure 3. Provides an illustration of the requirements when handlers cease operations.
Handler activity begins. Handlers
are NOT wearing APRs.
i
r
Sensory Irritation
i
r
Certified applicator in charge
decides to cease operations rather
than continue with respirators.
i
r
Handlers must stop work and
leave application block and buffer
zone.
i
r
If 2 samples taken at least 15
minutes apart (by a handler
wearing an APR) show
concentrations are less than 600
ppb and NO sensory irritation,
then
i
r
Resume operations.
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Figure 4. Provides an illustration of the requirements when handlers put on a respirator.
Handler activity begins. Handlers
are NOT wearing APRs.
Sensory Irritation
Certified applicator in charge
decides to continue operations.
All handlers in the application
block and buffer zone put on an
APR. Air monitoring program
begins.
Feel irritation through APR, OR
monitoring indicates
concentrations above 6000 ppb.
Handlers must stop work and
leave application block and buffer
zone.
If, 2 consecutive samples taken at
least 15 minutes apart, by a
handler wearing an APR are
above 600 ppb BUT below 6000
ppb, no sensory irritation is felt,
and the cartridge is changed, then
Resume operations wearing an
APR. Air monitoring continues.
If 2 consecutive samples taken at
least 15 minutes apart, by a
handler wearing an APR, are less
than 600 ppb and NO sensory
irritation, then
Resume operations without an
APR or remove respirator.
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Respiratory Protection Equipment
In the July 2008 RED, the Agency required handlers to wear an air purifying respirator
approved for MITC with a protection factor (PF) of 10. For additional clarity, even though
currently there are no air-purifying respirator cartridges certified by the Mine Safety and Health
Administration-National Institute for Occupational Safety and Health (MSHA-NIOSH) for
protection against MITC, NIOSH/OSHA does recommend respirators with organic vapor
cartridges for MITC use, and the Agency is requiring half-face respirators with organic-
cartridges be used when a respirator is necessary; the Agency will consider other APR-cartridges
combinations provided written certification of their efficacy against MITC is provided to the
Agency. The EPA assumes that half-face respirators have a protection factor of 10, therefore, the
respiratory protection will only be protective up to MITC concentrations of 6000 ppb, and if
concentrations exceed 6000 ppb (or if eye irritation occurs), operations must cease. At air
concentrations greater than 6000 ppb, the respirator is not designed to protect handlers from
inhaling more than 600 ppb of MITC. Therefore, the handler must continue to monitor once
respirators are donned. If concentrations of MITC exceed 6000 ppb or if eye irritation occurs,
then the operations must cease until levels of MITC are measured to be below 600 ppb from
consecutive air samples.
The Agency did receive comments regarding the cartridge recommendations, the
recommended equipment, and the assumed respirator protection factor. All of these comments
are addressed in detail in the following document located in the metam-sodium and metam-
potassium docket. Methyl Bromide, 1,3-Dichloropropene, Chloropicrin, Dazomet, Metam
Sodium/Potassium, MITC: Health Effects Division (HED) Component of Agency Response To
Comments On 2008 Reregistration Eligibility Documents (Dated May 14, 2009). The Agency
would like to clarify issues regarding the respiratory protection cartridges and respirators.
Comments suggested that the Agency require organic-vapor cartridges. This was the Agency's
intention in the July 2008 RED. Others commented on the use of full-face respirators and
goggles. The Agency is still recommending the use of organic-vapor cartridges when protection
is required.
Respirator fit testing, training, and medical qualification
As detailed in the July 2008 RED, the respirator protection factor described above in the
Respiratory Protection Equipment section is based on the following assumptions: 1) the
respirator is fit-tested, 2) proper respirator training occurs, and 3) an annual medical evaluation
and clearance is completed. Without these requirements, it is unclear whether the reduction in
inhalation exposure that is assumed by the protection factor will be achieved. In order to ensure
that the respiratory protection EPA is assuming is being achieved in the field, respiratory
requirements will include fit testing, respirator training, and annual medical evaluation.
During the post-RED comment period, the Agency received a variety of comments
ranging from full support of the requirement, to comments about the cost and time burden
associated with the requirement. The Agency also received several comments regarding the
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details of this requirement, for example who conducts the fit-testing and medical exam and what
the medical exam entails.
While EPA recognizes that there is a cost associated with the fit-testing, training, and
medical exam requirement the Agency still believes that respirator fit-testing, training, and
medical exams are a necessary part of the mitigation package. Since the Agency is now offering
a cease operations option where handlers can leave the application block and surrounding buffer
zone in lieu of putting on an air-purifying respirator, the Agency is only requiring that handlers
who wear a respirator are fit-tested, trained, and medically examined. The Agency believes that
this revision will reduce the cost associated with this requirement while still keeping the same
level of protection for the handlers that wear respirators. The following language must be added
to product labels:
"Employers must also ensure that any handler that uses a respirator is:
• Fit-tested and fit-checked using a program that conforms to OSHA's requirements (see 29
CFR Part 1910.134)
• Trained using a program that confirms to OSHA's requirements (see 29 CFR Part 1910.134)
• Examined by a qualified medical practitioner to ensure physical ability to safely wear the
style of respirator to be worn. A qualified medical practitioner is a physician or other
licensed health care professional (PLHCP) who will evaluate the ability of a worker to wear a
respirator. The initial evaluation consists of a questionnaire that asks about medical
conditions (such as a heart condition) that would be problematic for respirator use. If
concerns are identified, then additional evaluations, such as a physical exam, might be
necessary. The initial evaluation must be done before respirator use begins. It does not need
to be repeated unless the health status or respirator use conditions change."
Respirator availability
The handler employer must confirm and document in the FMP that enough air-purifying
respirators and cartridges are available for each handler that wears an air-purifying respirator.
The Agency is requiring that at minimum two handlers have the appropriate respirator and
cartridges available and that these handlers are fit-tested, trained, and medically examined.
Tarp Repair
The July 2008 RED required handlers to wear APRs if they perform tarp repair
operations before the entry-restricted period has ended. The requirements were different from
other handling activities because the duration of tarp repair activities was believed to be shorter
than other handling tasks and therefore tarp repair activities would not trigger the initial
monitoring requirement. Upon consideration of comments the Agency received on this
requirement, EPA has determined that respiratory protection for tarp repair activities should be
handled consistently with other handler activities, i.e., handlers repairing tarps are not required to
wear respirators unless sensory irritation is experienced. Additionally, the Agency believes that
tarp repair like other handling activities described above would benefit from the development of
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sensitive monitoring devices to reliably inform handlers if and when concentrations are above
the action level for respiratory protection. EPA will reevaluate this measure during Registration
Review or sooner if such devices are available in the short term.
5. Tarp perforation and removal
The Agency's risk assessment indicates that there is a risk concern for handlers during the
perforation (cutting, poking, punching, or slicing) and removal of tarps, and notes potential for
increased risk when high barrier tarps are used. To address these risks EPA required the
following mitigation in the July 2008 RED:
• Tarps cannot be perforated until a minimum of 5 days (120 hours) after fumigation was
complete.
• Tarps cannot be removed until 24 hours after tarp perforation is complete.
• If tarps are not removed after perforation, planting cannot start until 48 hours after
perforation is complete.
• If tarps are left intact for at least 14 days after the fumigation is complete then planting
can take place as tarps are being perforated.
• Broadcast tarps could be removed before 5 days if adverse weather compromised the
integrity of the tarp provided that at least 48 hours had passed since fumigation
completion, the buffer zone was extended until 24 hours after the tarp removal was
complete, and untreated areas in the application block are not treated for at least 24 hours
after tarp removal is complete.
• Tarp perforation must be done using mechanical methods.
• Each broadcast tarp panel must be perforated using a lengthwise cut.
During the post-RED comment period the Agency received comments on the tarp
perforation and removal requirements. In particular the Agency received comments on the
adequacy of the 5 day requirement for high barrier tarps to protect workers; the difficulty
implementing the 24 hour wait period between tarp perforation and removal; and concerns
regarding the weather condition exceptions, mechanical perforation, and broadcast panel
perforation.
There is some uncertainty regarding potential risks if high barrier tarps are perforated
after 5 days. This is because worker exposure data used in the risk assessments are generally
based on what has been the industry standard tarping technology, i.e., low or high density
polyethylene tarps, typically with higher application rates and no significant emphasis on using
the GAPs as defined in the RED. Data indicate that high barrier tarps are effective measures to
reduce fumigant emissions (see Methyl Bromide (PC Code 053201), Chloropicrin (PC Code
081501), Dazomet (PC Code 035602), Metam Sodium and Potassium (PC Codes 039003 &
039002), MITC (PC Code 068103), Updated Health Effects Division Recommendations for
Good Agricultural Practices and Associated Buffer Credits). While this reduction decreases the
risk to bystanders, it could increase the risk to handlers perforating or removing tarps because
more fumigant could be trapped between the soil surface and the tarp—currently California
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Department of Pesticide Regulation (CDPR) prohibits the use of methyl bromide with certain
high barrier tarps due to worker concerns.
Based on CDPR's prohibition and stakeholder's comments, EPA considered requiring a
longer interval such as 10 days before allowing high barrier tarps to be perforated. However,
EPA was concerned that adding such a requirement could discourage fumigators from using high
barrier tarps which potentially allow for lower application rates and reduce bystander risk
associated with offgassing. New studies currently underway which involve use of high barrier
tarps may enable EPA to refine estimates of handler risk in the future. EPA will consider these
data during Registration Review, or sooner as the information becomes available.
Since the Agency has designed the mitigation measures to work together and believes
that measures to address handler risks are likely to protect these handlers when the reduced rates
are considered in conjunction with other measures such as respiratory protection, GAPs, FMPs,
and training, EPA is not increasing the amount of days before high barrier tarps can be
perforated.
During earlier comment periods EPA heard from various stakeholders that windy
conditions sometimes caused tarps to blow off fields and create other hazards, e.g., to motorists
on nearby roadways. As a result, in the July 2008 RED the Agency provided an exception to
allow tarps to be removed after 48 hours under adverse weather conditions. During the post-
RED comment period EPA received comments that this exception did not fully address the issue
since the mitigation required waiting a minimum of 48 hours after fumigation but tarps could
blow of fields sooner than that. Commenters also said waiting 24 hours between tarp perforation
and removal and the requirement to cut every broadcast tarp panel added to the potential for tarps
to blow off fields and create other hazards: once tarps are cut they are prone to blowing off
when windy conditions occur. To decrease the potential of broadcast tarps blowing off
commenters also suggested that the Agency add flexibility to the 24 hour requirement by giving
tarp removers the option to remove tarps 2 hours after tarp perforation if monitoring indicated
levels below the Agency's LOG. Commenters also suggested that every 1-3 tarp panels should
be cut based on the professional judgment of the handler.
Upon review of the comments the Agency agrees that the mitigation should be revised
somewhat to allow for tarp removal at any time if the tarp is no longer performing its intended
function and it is creating other types of risk. Therefore, EPA is revising the exception outlined
in the RED to address these comments. EPA notes that handlers undertaking these tasks must
follow the respiratory protection procedures detailed in Section 4 (Respiratory Protection for
Handlers); this change still provides handler protection while reducing the unintended
consequences of tarps creating other hazards.
The Agency believes cutting every panel allows the fumigant trapped beneath each panel
to offgas before the tarp is removed. If each panel is not cut, it is not likely that necessary off-
gassing can take place to reduce risks to handlers removing tarps. The Agency understands that
the main concern for not cutting every panel is due to the potential for tarps to blow off and has
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determined that this concern is best addressed by modifying the 24-hour wait period. Tarps may
be removed 2 hours after tarp perforation is complete provided that tarp removers follow the
procedures set forth in the respiratory section of this document; therefore the risk to handlers will
not increase as a result of this modification. EPA considered the suggestion to monitor before
tarp removal begins; however, because of technical limitations with current technology the
Agency did not include monitoring as part of the mitigation. As with the respiratory protection
section, the Agency sees the value in a monitoring program if reliable and accurate devices are
available and will consider monitoring during Registration Review or sooner if information
becomes available.
The Agency received comments supporting the requirement for mechanical tarp
perforation, though other commenters stated that for some situations mechanical cutting is not
feasible. Examples cited included at the start of a row when a mechanical device such as an
ATV will be used to cut the tarps on the field, during flood prevention activities, and for small
fields. Based on comments, EPA believes these are necessary short-duration activities. Provided
the respiratory protection procedures for handlers are followed, these activities would not
increase the risk to handlers. With regard to small fields where mechanical cutting is not
feasible, the Agency considered the duration of the activity and the respiratory protection
considerations and will permit manual perforation only for application blocks that are 1 acre or
less in size.
As a result of the Agency's review and consideration of comments, the following
summarizes the revised mitigation measures to address inhalation risks from tarp perforation and
removal activities:
• As described in the Handler Definition section of this document tarp perforators and
removers are considered handlers for a specified duration and every handler must adhere
to the respiratory protection procedures outlined in the Respiratory Protection section of
this document.
• Tarps must not be perforated until a minimum of 5 days (120 hours) have elapsed after
the fumigant injection into the soil is complete (e.g., after injection of the fumigant
product and tarps have been laid or after drip lines have been purged and tarps have been
laid), unless a weather condition exists which necessitates the need for early perforation
or removal See Early Tarp Removal for Broadcast Applications Only and Early Tarp
Perforation with Seepage Irrigation sections below.
• If tarps will be removed after planting, tarp removal must not begin until at least 2 hours
after tarp perforation is complete.
• If tarps will not be removed before planting, planting or transplanting must not begin
until at least 48 hours after the tarp perforation is complete.
• If tarps are left intact for a minimum of 14 days after fumigant injection into the soil is
complete, planting or transplanting may take place while the tarps are being perforated.
• Each tarp panel used for broadcast fumigation must be perforated.
• Tarps used for fumigations may be perforated manually ONLY for the following
situations:
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o At the beginning of each row when a coulter blade (or other device which
performs similarly) is used on a motorized vehicle such as an ATV.
o In fields that are 1 acre or less.
o During early tarp removal in fields with seepage irrigation if rainfall necessitates
draining fields
• In all other instances tarps must be perforated (cut, punched, poked, or sliced) only by
mechanical methods.
• Tarp perforation for broadcast fumigations must be completed before noon, (seepage
irrigation exception)
• For broadcast fumigations tarps must not be perforated if rainfall is expected within 12
hours.
• Early Tarp Removal for Broadcast Applications Only:
o Tarps may be removed before the required 5 days (120 hours) if adverse weather
conditions have compromised the integrity of the tarp, provided that the
compromised tarp poses a safety hazard. Adverse weather includes high wind,
hail, or storms that blow tarps off the field and create a hazard, e.g., tarps blowing
into power lines and onto roads. A compromised tarp is a tarp that due to an
adverse weather condition is no longer performing its intended function and is
creating a hazard.
o If tarps are removed before the required 5 days have elapsed due to adverse
weather, the events must be documented in the post fumigation summary section
oftheFMP.
• Early Tarp Perforation with Seepage Irrigation
o Tarp perforation is allowed before the 5 days (120 hours) have elapsed if rain
necessitates field drainage.
o Tarps must be immediately retucked and packed after soil removal.
o Subsequent tarp perforations must not occur until the original 5 days have
elapsed.
o The events must be documented in the post fumigation summary section of the
FMP."
o
6. Entry Prohibitions
Most of the current metam-sodium and metam-potassium labels allow reentry to the
treated field by workers 48 hours after application. The risk assessment indicates that risks
exceed EPA's level of concern for workers entering fields after 48 hours. However, the risk
assessment indicates that extending this period decreases this risk. In addition, stakeholder
comments prior to the July 2008 RED indicated that non-handler entry to perform post-
application (i.e., non-handler) tasks is generally not needed for at least 7 to 14 days following the
completion of the application and could reduce the effectiveness of the fumigation by disturbing
the soil thus allowing the fumigate to escape the soil before it effectively controls pests.
Due to the volatile nature of metam-sodium and metam-potassium and the potential for
worker exposure, in the July 2008 RED the Agency restricted entry into the treated area by
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anyone other than a protected handler. This restriction differs from a restricted entry interval
(REI), that is currently required for most conventional pesticides, which contains exceptions for
workers doing certain tasks before the REI has expired (e.g., scouting). Workers permitted entry
under the REI are prohibited for soil fumigants. Under the Worker Protection Standard (WPS),
exceptions allow certain tasks to take place before the REI has expired as long as dermal contact
with treated surfaces will be limited; however for fumigants where inhalation exposure is the
primary risk concern, entry to a treated area is further restricted.
During the post-RED comment period, the Agency received comments that indicated the
opposite of the comments received in phase 5. The post-RED comments stressed that the
restriction would prohibit certain activities from taking place and that the restrictions were not
warranted. Based on discussions with stakeholders and the risks identified, EPA does not
believe that the entry restricted period will have a substantial impact on agricultural operations,
and the Agency is not making any changes to the July 2008 RED mitigation listed below.
EPA believes that risks will not exceed the Agency's level of concern, provided entry
(including early entry that would otherwise be permitted under the WPS) by any person—other
than a correctly trained and PPE-equipped handler who is performing a handling task—is
prohibited from the start of the application until:
• 5 days (120 hours) after application has ended for untarped applications, or
• After tarps are perforated and removed if tarp removal is completed less than 14 days
after application, or
• 48 hours after tarps are perforated if they will not be removed prior to planting, or
• 5 days (120 hours) after application is complete if tarps are not perforated and removed
14 days after the application is complete.
Figures 5, 6, 7, and 8 provide illustrations of tarp perforation/removal and entry
prohibition mitigation required for various metam-sodium and metam-potassium applications.
The intervals depicted are the minimum that must be followed.
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FigureS. Untarped Applications
48 hours
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Figure 6. Tarp Broadcast Applications (tarps removed before planting)
5 days (120 hours)
2 hours
Tarp
Removal
Begins
Tarp
Removal
Ends
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Figure 7. Tarp Bed Applications (Tarps not removed before planting)
5 days (120 hours)
48 hours
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Figure 8. Tarp Bed/Broadcast Applications (Tarps are not perforated until 14 days after
application)
5 days (120 hours)
14 days
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cc. Other Risk Mitigation
1. Restricted Use Pesticide (RUP) Classification
All soil fumigant products containing methyl bromide, 1,3-dichloropropene (Telone®),
iodomethane, and chloropicrin are currently classified as RUPs. Soil fumigant products
containing metam-sodium and metam-potassium are currently unclassified as such. However,
MITC, the byproduct of metam-sodium and metam-potassium, has characteristics that meet the
criteria for restricted use for both human hazard criteria (as specified in 40 CFR 152.170(b)) and
from other evidence (as specified in 40 CFR 152.170(d)) including use history and incident data
from exposure to MITC.
Human Hazard Criteria
The acute toxicity profile of MITC shows it is more acutely toxic (toxicity categories are
all I or II) than metam-sodium and metam-potassium (mostly toxicity categories III and IV).
While the product toxicity of metam-sodium and metam-potassium do not meet the hazard
criteria for classification as restricted use, the degradate product of MITC, which both handlers
and bystanders can be exposed to, does meet the criteria.
Other Evidence
If any soil fumigant is not applied correctly, bystanders may be exposed to concentrations
that exceed levels of concern and that could cause significant adverse effects. There is a history
of incidents involving metam-sodium in which multiple bystanders experienced illness/injury
despite being several hundred to several thousand feet from the treated area. The application of
soil fumigants can pose hazards for several hours from the time of application to several days
after application. Depending on the situation, worker and/or area air monitoring may be required
to ensure that exposure limits are not exceeded. Special equipment is often needed to apply soil
fumigant safely and accurately (e.g., compaction rig, tarp equipment, self-contained breathing
apparatus). To apply soil fumigants safely and ensure bystanders and applicators are not
adversely affected, handlers also need specialized skills and training.
In sum, metam-sodium and metam-potassium meet the standard for restricted use because:
• The application of these fumigants involves complex operations requiring specialized
training and/or experience.
• Fumigant label directions call for specialized apparatus and protective equipment that is
not available to the general public.
• A minor failure to follow label directions may result in severe adverse effects.
• Even if directions for use are followed, use may result in discernible adverse effects, of
both direct and indirect nature, on non-target organisms.
Therefore, the Agency has determined that all metam-sodium and metam-potassium soil
fumigant products must be classified as restricted use. Label requirements will include the
following details, which are also contained in the attached label table.
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Requirement on Labels
"Restricted Use Pesticide due to acute inhalation toxicity to humans."
"For retail sale to and use by Certified Applicators or persons under their direct supervision and
only for those uses covered by the Certified Applicator's certification."
In order to ensure that a certified applicator is at the application site, the label will also state,
"the certified applicator supervising the application must be at the fumigant application site and
able to maintain visual contact with every handler participating in the application starting when
the fumigant is first introduced into the soil and ending after the fumigant has stopped being
delivered/dispensed to the soil and the soil is sealed."
2. Good Agricultural Practices (GAPs)
Since the application methods and work practices of fumigators have direct impacts on
the amount of fumigant applied and emitted, the Agency determined that labeling should require
proven practices that will reduce risks to handlers, bystanders, and the environment. Registrants,
applicators, growers, and other stakeholders have consistently reported to the Agency that GAPs
are a key mitigation measure to reduce the amount of fumigants applied and fumigant emissions.
The purpose of this section in the July 2008 RED was to specify good agricultural
practices (GAPs) that were required for soil applications of metam-sodium and metam-
potassium. The practices specified contribute to reducing emissions and thereby are expected to
reduce potential for worker and bystander exposures.
The Agency received comments regarding the GAPs outlined in the July 2008 RED.
These comments addressed a range of topics:
• making the GAPs voluntary rather than mandatory label requirements,
• buffer zone credits associated with GAP implementation,
• wind speed requirements and the description of inversion conditions,
• crop residue requirements,
• application equipment requirements,
• soil moisture and temperature requirements,
• flexibility in the event that new GAPs are developed,
• enforceability of GAPs,
• university research exemptions, and
These comments are addressed in detail in the Special Review and Reregi strati on
Division's response to comments document. Based on the comments, the Agency has revised
some of the GAPs, and will continue to review GAPs as the Agency finalizes the soil fumigant
labels.
The GAPs outlined in the RED and this RED amendment has been shown to reduce
emissions and bystander exposures and will continue to be mandatory label requirements. Buffer
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zone credits have been reanalyzed and additional credits have been calculated for various GAPs
depending on the soil fumigant used (see buffer zone credit section).
The Agency has clarified the language regarding inversions and wind speed
requirements. The Agency agrees that erosion control is an important consideration. However,
removing the crop residue prior to fumigation is important to limit the natural "chimneys" that
will occur in the soil when crop residue is present. These "chimneys" allow the soil fumigants to
move through the soil quickly and escape into the atmosphere. This may create potentially
harmful conditions for workers and bystanders and will limit the efficacy of the fumigant. To
accommodate both of these important considerations (erosion control and human health
protection), the Agency encourages that the field be cleared of crop residue as close to the timing
of the fumigation as possible to limit the length of time that the soil would be exposed to
potentially erosive weather conditions.
Note: The Agency plans to work with the registrants and other stakeholders to refine the GAPa
for metam-sodium and metam-potassium prior to the 2010 and 2011 growing season.
Weather Conditions
The Agency received many comments related to the inversion label language including:
concern that some of the characteristics of inversion conditions (like misty conditions or clear
skies at night) do not always indicate the presence of an inversion: relying on a weather forecast
to predict inversions is unreliable and not enforceable: and that prohibiting application during
inversions does not address concerns of inversions during the off-gassing period.
Based on these comments the Agency has revised the "weather conditions" section of the
GAPs that relates to temperature inversions to clarify that parts of the weather conditions that are
requirements and those that are included to help guide the applicator to identify temperature
inversions. The measures have also been updated to prohibit application only if temperature
inversion conditions are forecasted to persist for more than 18 of the 48 hours after the start of
the application since this will filter out conditions when diurnal temperature inversions may
occur, though even diurnal temperature inversions could contribute to exposures to fumigant
concentrations outside buffers. As such, EPA believes that the measures described below in the
emergency preparedness and response section of this document are important to address potential
risks associated with shorter-term diurnal inversions. The Agency is also changing the wind
speed requirement so winds may either be 2 mph at the start of application or be forecasted to
reach 5 mph during the application. These changes are designed to prevent applications when
inversion conditions are predicted to occur after the application has begun, since this is the time
when the peak off-gassing is expected to occur.
Stakeholders also questioned where the inversion conditions must exist and to what
extent the temperature inversion must exist that would prevent an application. The Agency has
provided additional temperature inversion details and has added a prohibition for application
during an air-stagnation advisory. Air-stagnation advisories are issued through the National
Weather Service and usually capture long periods of air stillness that may remain in an area from
one to several days. EPA has determined that these modifications achieve the same goals as the
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2008 RED since they provide additional clarity that will enhance users' ability to practically
comply with the requirements. The revised statements are stated below.
The following are mandatory GAPs that must be followed during all applications, as
specified below. All measurements and other documentation planned to ensure that the
mandatory GAPs are achieved must be recorded in the FMP and/or the post application summary
report.
Registrants may also include optional GAPs that reduce emission on product labels.
Some of the optional GAPs may qualify for buffer zone credits (e.g., reduced soil temperature,
use of high barrier tarps, increased soil organic matter, and soils with increased clay content).
All measurements and other documentation planned to ensure that the optional GAPs are
achieved must be recorded in the FMP and/or the post application summary report.
GAPS for Ground-rig Applications (Shank, Spray Blade, Rotary Tiller, etc.)
Wind Speed
• Wind speed at the application site must be a minimum of 2 mph at the start of the application
or forecasted to reach at least 5 mph during the application.
Weather conditions
• Prior to fumigation the weather forecast for the day of the application and the 48-hour period
following the fumigation must be checked to determine if unfavorable weather conditions
exist or are predicted and whether fumigation should proceed.
• Do not apply if a shallow, compressed (low-level) temperature inversion is forecast to persist
for more than 18 consecutive hours for the 48-hour period after the start of application, or if
there is an air-stagnation advisory in effect for the area in which the fumigation is planned.
• Detailed local forecasts for weather conditions, wind speed, and air stagnation advisories
may be obtained on-line at: http://www.nws.noaa.gov. For further guidance, contact your
local National Weather Service Forecasting Office.
Identifying Unfavorable Weather Conditions
• Unfavorable weather conditions block upward movement of air, which results in trapping
fumigant vapors near the ground. The resulting air mass can move off-site in unpredictable
directions and cause injury to humans, animals or property. These conditions typically exist
prior to sunset and continue past sunrise and persist as late as noontime. Unfavorable
conditions are common on nights with limited cloud cover and light to no wind and their
presence can be indicated by ground fog or smog and can also be identified by smoke from a
ground source that flattens out below a ceiling layer and moves laterally in a concentrated
cloud.
Soil Conditions, Injection Depth and Soil Sealing
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• Soil must be in good tilth and free of large clods at the surface. If subsurface soil
compaction layers (hardpans) are present within the intended fumigation treatment zone,
a deep tillage to fracture these layers must occur prior to the soil fumigant application.
• Field residue and stubble must be worked into the soil with little or no crop residue
present on the soil surface. Crop residue that is present must not interfere with the soil
seal. Removing the crop residue prior to fumigation is important to limit the natural
"chimneys" that will occur in the soil when crop residue is present. These "chimneys"
allow the soil fumigants to move through the soil quickly and escape into the atmosphere.
This may create potentially harmful conditions for workers and bystanders and will limit
the efficacy of the fumigant. However, crop residue on the field serves to prevent soil
erosion from both wind and water and is an important consideration. To accommodate
erosion control, fumigant efficacy, and human health protection, clear fields of crop
residue as close to the timing of the fumigation as possible to limit the length of time that
the soil would be exposed to potentially erosive weather conditions.
• For shank injection applications: The injection point for bedded and broadcast shank
injection applications shall be a minimum of 3 inches from the post-application soil
surface. Chisel traces must be eliminated following an application and the soil surface
must be compacted immediately with a culti-packer, ring roller, coil packer, soil-
crumbier basket, bed-shaper, or other similar equipment.
• For spray blade and rotary tiller applications: Spray or drip the product mixture on the
soil immediately ahead of the bed-shaping equipment or tiller. The soil surface must be
compacted immediately after application using a culti-packer, ring roller, soil-crumbier
basket, bed-shaper, or other similar equipment.
Soil temperature
• For all ground-rig applications, the maximum soil temperature measured throughout the
treatment area at a three-inch soil depth must be between 90-40 degrees F.
Soil Moisture
• Soil moisture, at the start of an application, must be at 60-80% field capacity two to six
inches below the soil surface.
• To achieve soil moisture at 60-80% field capacity, water treatments before or during the
application, or tillage before or during the application may be necessary.
• To conserve soil moisture, pretreatment water or tillage should be done as close to the
time of application as possible.
• The soil shall contain at the time of application enough moisture two to six inches below
the surface to meet the Fee I Method test as appropriate for the soil texture. .
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coarse textured soils (fine sand and loamy fine sand) there must be enough moisture (50
to 75 percent available soil water moisture) so the soil is moist, forms a weak ball with
loose and clustered sand grains on fingers, darkened color, moderate water staining on
fingers, will not ribbon.
moderately coarse textured soils (sandy loam and fine sandy loam) there must be
enough moisture (50 to 75 percent available soil water moisture) so the soil is moist,
forms a ball with defined finger marks, very light soil/water staining on fingers, darkened
color will not stick.
medium textured soils (sandy clay loam, loam, and silt loam) there must be enough
moisture (50 to 75 percent available soil water moisture) so the soil is moist, forms a ball,
very light staining on fingers, darkened color, pliable, and forms a weak ribbon between
the thumb and forefinger.
fine textured soils (clay, clay loam, and silty clay loam) there must be enough moisture
(50 to 75 percent available soil water moisture) so the soil is moist, forms a smooth ball
with defined finger marks, light soil/water staining on fingers, ribbons between thumb
and forefinger.
For fields with more than one soil texture, soil moisture content in the lightest textured
(most sandy) areas must comply with this soil moisture requirement. Whenever possible, the
field should be divided into areas of similar soil texture and the soil moisture of each area should
be adjusted as needed. Coarser textured soils can be fumigated under conditions of higher soil
moisture than finer textured soils; however, if the soil moisture is too high, fumigant movement
will be retarded and effectiveness of the treatment will be reduced. Previous and/or local
experience with the soil to be treated or the crop to be planted can often serve as a guide to
conditions that will be acceptable. If there is uncertainty in determining the soil moisture content
of the area to be treated, a local extension service or soil conservation service specialist or pest
control advisor (agriculture consultant) should be consulted for assistance.
Prevention of Spillage
• Do not apply or allow fumigant to drain onto the soil surface.
Application and Equipment Considerations
• Injectors must be placed below the soil surface before product flow begins.
• Clear lines before lifting injectors from the soil.
• Each injection line must have a check valve located as close as possible to the final
injection point.
• Use only tanks, hoses and fittings approved for metam.
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• Dry connect fittings (closed transfer system) must be installed on all tanks and transfer
hoses.
• All systems must be equipped with an individual tank monitoring system to detect flow
problems in each individual tank.
• Each nozzle must be equipped with a flow monitor, e.g. mechanical, electronic, or Red-
ball type monitor.
• Prior to applications, the applicator must ensure that:
• Application equipment is in good working order,
• All tanks, hoses, fittings, valves and connections are tightened, sealed and not
leaking,
• Tank monitoring equipment, flow monitoring equipment and check valves are
functioning properly,
• There is no damage to hoses or piping,
• Sight gauges and pressure gauges are working,
• Nozzles and metering devices are of correct size and are sealed and unobstructed,
• All shields are in place.
Tarps
• When tarps are used in tractor applications, the tarps must be installed immediately after
application.
• Only approved tarps identified in this document, in the section titled "Buffer Zone
Reduction Credits", may be used for credits towards reducing the buffer.
• A written tarp plan must be developed and included in the FMP that includes:
o Schedule and procedures for checking tarpaulins for damage, tears, and other
problems,
o Plans for determining when and how repairs to tarp will be made, and by whom,
o Minimum time following injection that tarp will be repaired,
o Minimum size of damage that will be repaired,
o Other factors used to determine when tarp repair will be conducted,
o Schedule, equipment and methods used to cut tarp,
o Aeration plans and procedures following cutting and /or slitting prior to tarp removal
or planting, and
o Schedule, equipment, and procedures for tarp removal.
GAPS for Sprinkler and Chemigation Applications
Wind Speed
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• For mid-release, high-release and end-gun sprinkler or chemigation applications as
defined by U.S. EPA, wind speed at the application site must be a minimum of 2 mph at
the start of the application or forecasted to reach 5 mph during the application and the
maximum wind speed is 8 mph.
• For low-release sprinkler or chemigation applications as defined by U.S. EPA, wind
speed at the application site must be a minimum of 2 mph at the start of the application or
forecasted to reach 5 mph during the application and the maximum wind speed is 25 mph.
Wind Speed
Wind speed at the application site must be a minimum of 2 mph at the start of the application
or forecasted to reach at least 5 mph during the application.
Weather conditions
Prior to fumigation the weather forecast for the day of the application and the 48-hour period
following the fumigation must be checked to determine if unfavorable weather conditions
exist or are predicted and whether fumigation should proceed.
Do not apply if a shallow, compressed (low-level) temperature inversion is forecast to persist
for more than 18 consecutive hours for the 48-hour period after the start of application, or if
there is an air-stagnation advisory in effect for the area in which the fumigation is planned.
Detailed local forecasts for weather conditions, wind speed, and air stagnation advisories
may be obtained on-line at: http://www.nws.noaa.gov. For further guidance, contact your
local National Weather Service Forecasting Office.
Identifying Unfavorable Weather Conditions
Unfavorable weather conditions block upward movement of air, which results in trapping
fumigant vapors near the ground. The resulting air mass can move off-site in unpredictable
directions and cause injury to humans, animals or property. These conditions typically exist
prior to sunset and continue past sunrise and persist as late as noontime. Unfavorable
conditions are common on nights with limited cloud cover and light to no wind and their
presence can be indicated by ground fog or smog and can also be identified by smoke from a
ground source that flattens out below a ceiling layer and moves laterally in a concentrated
cloud.
Soil Conditions
• Soil must be in good tilth and free of large clods at the surface. If subsurface soil
compaction layers (hardpans) are present within the intended fumigation treatment zone,
a deep tillage to fracture these layers must occur prior to the soil fumigant application.
• Field residue and stubble must be worked into the soil with little or no crop residue
present on the soil surface. Crop residue that is present must not interfere with the soil
seal. Removing the crop residue prior to fumigation is important to limit the natural
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"chimneys" that will occur in the soil when crop residue is present. These "chimneys"
allow the soil fumigants to move through the soil quickly and escape into the atmosphere.
This may create potentially harmful conditions for workers and bystanders and will limit
the efficacy of the fumigant. However, crop residue on the field serves to prevent soil
erosion from both wind and water and is an important consideration. To accommodate
erosion control, fumigant efficacy, and human health protection, clear fields of crop
residue as close to the timing of the fumigation as possible to limit the length of time that
the soil would be exposed to potentially erosive weather conditions.
Air Temperature
• The maximum air temperature is 90 degrees F.
Soil temperature
• The maximum soil temperature, measured at a three-inch soil depth, is 90 degrees F.
Soil Moisture
• Apply sufficient water before or during the application to ensure soil moisture at 60-80%
field capacity at a minimum of two to six inches below the soil surface at the start of the
application.
Flushing Irrigation Lines
• Do not allow fumigant to remain in the irrigation system after the application is
complete. After application of the fumigant, flush the injection and irrigation system
with untreated water. The flush time must be adequate to purge the fumigant from the
injection and irrigation system, but should be less than the amount that could over-
saturate the beds. If common lines are used for both the fumigant application and a water
treatment/seal (if applied), these lines must be adequately flushed before starting the
water treatment/seal.
Set-up, Repair and Maintenance of Equipment
• Anti-siphon and back-flow prevention devices must be installed and in working order.
• Storage tanks must be inspected, in good condition, and not past their life expectancy to
ensure product does not spill or leak.
• Storage tanks must have proper pesticide labels on them.
• Install a shut-off valve on the tank outlet to secure the bulk storage tank when not in use.
Use only tanks constructed with materials approved for handling metam-
sodium/metam-potassium.
Inter-connect the pump power supply and injection pump so that, if the center pivot
or linear move stops, the injection pump shuts off.
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GAPs for Drip Application
Wind Speed
• Wind speed at the application site must be a minimum of 2 mph at the start of the application
or forecasted to reach at least 5 mph during the application.
Weather conditions
• Prior to fumigation the weather forecast for the day of the application and the 48-hour period
following the fumigation must be checked to determine if unfavorable weather conditions
exist or are predicted and whether fumigation should proceed.
• Do not apply if a shallow, compressed (low-level) temperature inversion is forecast to persist
for more than 18 consecutive hours for the 48-hour period after the start of application, or if
there is an air-stagnation advisory in effect for the area in which the fumigation is planned.
• Detailed local forecasts for weather conditions, wind speed, and air stagnation advisories
may be obtained on-line at: http://www.nws.noaa.gov. For further guidance, contact your
local National Weather Service Forecasting Office.
Identifying Unfavorable Weather Conditions
• Unfavorable weather conditions block upward movement of air, which results in trapping
fumigant vapors near the ground. The resulting air mass can move off-site in unpredictable
directions and cause injury to humans, animals or property. These conditions typically exist
prior to sunset and continue past sunrise and persist as late as noontime. Unfavorable
conditions are common on nights with limited cloud cover and light to no wind and their
presence can be indicated by ground fog or smog and can also be identified by smoke from a
ground source that flattens out below a ceiling layer and moves laterally in a concentrated
cloud.
Soil Conditions
• Soil must be in good tilth and free of large clods at the surface. If subsurface soil
compaction layers (hardpans) are present within the intended fumigation treatment zone,
a deep tillage to fracture these layers must occur prior to the soil fumigant application.
• Field residue and stubble must be worked into the soil with little or no crop residue
present on the soil surface. Crop residue that is present must not interfere with the soil
seal. Removing the crop residue prior to fumigation is important to limit the natural
"chimneys" that will occur in the soil when crop residue is present. These "chimneys"
allow the soil fumigants to move through the soil quickly and escape into the atmosphere.
This may create potentially harmful conditions for workers and bystanders and will limit
the efficacy of the fumigant. However, crop residue on the field serves to prevent soil
erosion from both wind and water and is an important consideration. To accommodate
erosion control, fumigant efficacy, and human health protection, clear fields of crop
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residue as close to the timing of the fumigation as possible to limit the length of time that
the soil would be exposed to potentially erosive weather conditions.
Soil Temperature
• The maximum soil temperature is 90 degrees F, measured at three inches in depth.
Set-up, Repair and Maintenance of Equipment
• Properly label metam-sodium storage tanks.
• Install a shut-off valve to secure the bulk storage tank when not in use.
• Use only tanks constructed with materials approved for handling metam products.
• The drip irrigation system (main lines, headers, drip tape) must be thoroughly checked for
leaks before the start of the application. An adequate run-time and pressure are needed to
detect leaks. Look for puddling along major pipes (holes on pipes or leaky joints), at the
top and ends of rows (leaky connections, open drip tape), in the furrows and on the bed
surface (damaged drip tape, malfunctioning emitters).
• To inject fumigant, use a metering system, effectively designed and constructed of
materials that are compatible with the fumigant and capable of being fitted with system
interlocking controls.
• The system must contain a functional back-flow/check valve and low-pressure drain
appropriately located on the irrigation pipeline to prevent water source contamination and
backflow.
• The fumigant injection system must contain a functional, automatic, quick-closing check
valve to prevent the flow of fumigant back toward the fumigant container.
• The fumigant injection system must contain a functional, normally closed valve located
on the intake side of the injection point and connected to the system interlock to prevent
fumigant from being withdrawn from the supply tank when the irrigation system is either
automatically or manually shut down.
• The system must contain functional interlocking controls to automatically shut off the
fumigant injection when the irrigation water flow stops or decreases to the point where
fumigant distribution is adversely affected.
Tarps
• When tarps are used in drip irrigation the tarps must be installed immediately after
application.
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• Only tarps mentioned previously in this document (in the subsection titled "Buffer Zone
Reduction Credits", may be used for credits towards reducing the buffer.
• A written tarp plan must be developed and included in the FMP that that includes:
o Schedule and procedures for checking tarpaulins for damage, tears, and other
problems,
o Plans for determining when and how repairs to tarp will be made, and by whom,
o Minimum time following injection that tarp will be repaired,
o Minimum size of damage that will be repaired,
o Other factors used to determine when tarp repair will be conducted,
o Schedule, equipment and methods used to cut tarp,
o Aeration plans and procedures following cutting and /or slitting prior to tarp removal
or planting, and
o Schedule, equipment, and procedures for tarp removal.
Flushing Drip Irrigation Lines
• After application of the fumigant, flush the injection and irrigation system with untreated
water. Do not allow fumigant to remain in the irrigation system after the application is
complete. The total volume of water must be adequate to completely remove the
fumigant from the irrigation system. If common lines are used for both the fumigant
application and a water treatment/seal (if applied), these lines must be adequately flushed
before starting the water treatment/seal.
3. Fumigant Management Plans (FMPs)
As noted elsewhere in this document, soil fumigation is a complex site-specific activity.
Failure to adhere to label requirements and procedures for safe use has led to accidents affecting
workers involved in fumigations as well as bystanders. Information from various sources shows
that health and safety plans, FMPs in this context, typically reduce workplace injuries and
accidents by prescribing a series of operational requirements and criteria. In fact plans like these
are widely implemented in a variety of industries and are recommended as standard approaches
for occupational health and safety management by groups such as American Industrial Hygiene
Association9 (i.e., through "Administrative" and "Workplace" controls). The Centers for Disease
Control provides guidance for developing health and safety plans in agricultural settings.10 The
effectiveness of similar plans has also been evaluated in the literature. Examples include
"lookback" reviews conducted by the Occupational Safety and Health Administration (OSHA)
which essentially implemented standards in various industries then reviewed their effectiveness
in this process as they are required to determine whether the standards should be maintained
without change, rescinded or modified. OSHA is required by Section 610 of the Regulatory
9 Ignacio and Bullock (2006) A Strategy For Assessing and Managing Occupational Exposures (Third Edition),
American Industrial Hygiene Association, AIHA Press 2700 Prosperity Avenue, Suite 250 Fairfax VA 22031 (ISBN
1-931504-69-5)
10 Karsky (2002) Developing a Safety and Health Program to Reduce Injuries and Accident Losses, Centers For
Disease Control National Ag Safety Database, available at http://www.cdc.gov/nasd/docs/d001501-
dOO 1600/dOO 1571/dOO 1571 .html
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Flexibility Act (5 U.S.C. 610) and Executive Order 12866 to conduct the "lookback" reviews.
These reviews are conducted to make the subject final standards more effective or less
burdensome in achieving their objectives, to bring them into better alignment with the objectives
of Executive Order 12866, and to make them consistent with the objectives of the Regulatory
Flexibility Act. Two examples of "lookback" reviews that support the use of FMPs for soil
fumigant health and safety management include: ethylene oxide use as a fumigant/sterilant, and
grain handling facilities requirements.11
In the July 2008 RED, EPA required FMPs to be completed before a fumigant
application occurs. EPA concluded that FMPs will reduce potential risks to bystanders as well as
handlers by requiring that applicators have carefully planned, in writing, each major element of
the fumigation. In this context, an FMP is a set of performance criteria for each application,
including how the fumigator intends to comply with label requirements. As added benefits, the
Agency determined that FMPs would ensure directions on the product labels were followed and
that the conditions under which fumigation occurred were documented. EPA also concluded that
FMPs would help ensure an appropriate response by the applicator or others involved in the
application should an incident occur since a proper and prompt response would reduce the
potential risk to bystanders from potential high exposure situations (e.g., readily available first
responder contact information could reduce response times to impacted bystanders and carefully
thought out emergency response plans can help ensure appropriate actions are taken in case of
unforeseen events).
The July 2008 RED provided a list of each major element FMPs would need to address.
These included general site and applicator information, application procedures, and a description
of how the fumigator planned to comply with label requirements for GAPs, buffer zones,
monitoring, worker protection, posting, and providing notification to the state or tribal lead
agency. FMPs also were required to include plans for communication between the applicator
and others involved in the fumigation, documentation, and handling emergency situation.
Additionally, EPA required that applicators complete a post fumigation summary that described
any deviations from the FMP, measurements taken to comply with GAPs, and information about
any problems such as complaints or incidents that occurred as a result of the fumigation. The
RED also specified requirements for record keeping and that FMPs must be provided, upon
request, to enforcement officials and handlers involved in the fumigation.
According to stakeholder comments in earlier comment periods, much of the information
required for the site-specific FMP was already being documented by users, and most industry
stakeholders supported mandatory FMPs provided they are not too restrictive or complex and do
not result in an excessive administrative burden.
During the post RED comment period, EPA received several comments regarding FMPs.
Stakeholders noted that much of the information required for the site-specific FMP is already
being documented by users and most industry stakeholders supported mandatory FMPs provided
they are not too restrictive or complex. Several comments from industry and user stakeholders
expressed concern that FMP requirements would increase paperwork burden without providing
11 United States Department of Labor, Occupational Safety and Health Administration (2008) Lookback Reviews
available at http://www.osha.gov/dea/lookback.html
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significant risk reduction, though others supported FMPs provided they did not result in an
excessive administrative burden. A number of comments suggested that the level of detail EPA
had required was too great and could result in voluminous, resource-intensive plans. Some of
these comments suggested that a checklist format would be more efficient and far less
burdensome. Some comments expressed reservations about the ability of FMPs to enhance
compliance with label requirements. Some commenters were concerned about the feasibility of
providing a copy of the FMP to on-site handlers or enforcement personnel, though others said
that copies of the FMP should be provided to workers in areas adjacent to the application block.
Following EPA's review of the post-RED comments, the Agency still believes that
FMPs will reduce potential risks to bystanders as well as handlers and are a key component of
the package of measures to reduce risks. EPA believes that FMPs will also enhance
compliance by requiring that applicators verify and document compliance with the label
requirements during and after application events are completed. In cases where errors may
have occurred, a post-application summary may also prevent similar problems from occurring
during future applications. However, in response to comments, the Agency has somewhat
modified the list of elements that must be addressed in the FMP (as described below) to make
it more streamlined and thus less burdensome to applicators and growers. In addition, the
Agency has developed a sample template in which many of the elements are covered in
checklist format, which fumigators have the option of downloading and modifying to meet the
needs of their specific fumigation situations. See:
http://www.epa.gov/pesticides/reregistration/soil_fumigants/. EPA will also continue to work
with stakeholders to refine the FMP template and potentially develop others so it is a more
useful tool for ensuring the safe application of metam-sodium and metam-potassium.
The Agency estimates that, if a certified applicator decides not to use the FMP template
and decides to prepare a narrative FMP, a carefully designed FMP could take several hours to
develop the first time. Subsequent FMPs should require substantially less time to develop
because much of the information can be reused from the initial plan. In addition, an enterprise
fumigating multiple application blocks as part of a larger fumigation may format their FMP in a
manner whereby all of the information that is common to all the application blocks is captured
once, and any information unique to a particular application block or blocks is captured in
subsequent, separate sections.
Amended FMP Requirements
Consistent with the July 2008 RED, the Agency is not requiring FMPs to be submitted to
state or local agencies. They must, however be maintained by the applicator and grower, (if the
grower is not the applicator), for a period of 2 years.
The Agency agrees with comments that having both the applicator and the
owner/operator provide copies of the FMP to handlers is unnecessarily duplicative and that
providing each worker with a hardcopy of the FMP wastes paper. The Agency also agrees that it
is not necessary for the FMP to be provided to the workers in areas adjacent to the application
block. Workers in adjacent areas will be notified of the fumigation by buffer posting
requirements and, in the case of neighbors whose land is part of a buffer zone, the adjoining
neighbor has responsibility for workers in areas adjacent to the application for which permission
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was granted to use as part of a fumigation buffer. The Agency has revised the following
requirement that was included in the 2008 RED, "Once the application begins, the certified
applicator and owner/operator of the application block must provide a copy of the FMP to
handlers involved in the fumigation, workers in adjacent areas to the application block, and
federal/state/local enforcement personnel, upon request." The RED Amendment requires the
certified applicator to make a copy of the FMP available for viewing by handlers involved in the
fumigation. The certified applicator or the owner/operator of the application block must provide
a copy of the FMP to any federal, state, tribal, or local enforcement personnel who request the
FMP. In the case of an emergency, the FMP must be made available when requested by
federal/state/local emergency response and enforcement personnel.
The Agency agrees with comments that the term "etc." complicates enforcement
activities and has removed that term from the labels.
Each site-specific FMP must contain the following elements:
»»» Applicator information (name, phone number, license number, employer name, employer
address, date of completing registrant methyl bromide training program)
*»* General site information
> Application block location, address, or global positioning system (GPS) coordinates
> Name, address, and, phone number of owner/operator of the application block
> Map, aerial photo, or detailed sketch showing field location, dimensions, buffer zones,
property lines, roads, rights-of-ways, sidewalks, permanent walking paths, bus stops,
water bodies, wells, nearby application blocks, surrounding structures (occupied and non-
occupied), locations of posted signs for buffers, and sites requiring 1A or Vs mile buffer
zones (e.g., schools (preschool to grade 12), state licensed day care centers, nursing
homes, assisted living facilities, hospitals, in-patient clinics and prisons) with distances
from the application site labeled
»»» General application information (target application date/window, brand name of fumigant,
EPA registration number
*»* Tarp Information and procedures for repair, perforation and removal (if tarp is used)
> Brand name, lot number, thickness
> Name and phone number of person responsible for repairing tarps
> Schedule for checking tarps for damage, tears, and other problems
> Maximum time following notification of damage that the person(s) responsible for tarp
repair will respond
> Minimum time following application that tarp will be repaired
> Minimum size of damage that will be repaired
> Other factors used to determine when tarp repair will be conducted
> Name and phone number of person responsible for cutting and/or removing tarps (if other
than certified applicator)
> Equipment/methods used to cut tarps
> Schedule and target dates for cutting tarps
> Schedule and target dates for removing tarps
»»» Soil conditions (description of soil texture in application block, method used to determine
soil moisture
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Weather conditions (summary of forecasted conditions for the day of the application and the
48-hour period following the fumigant application)
> Wind speed
> Inversion conditions (e.g., shallow, compressed (low-level) temperature inversion)
> Air stagnation advisory
Buffer zones
> Application method
> Application rate from lookup table on label (Ib ai/A)
> Application block size from lookup table on label (acres)
> Credits applied
> Buffer zone distance
> Description of areas in the buffer zone that are not under the control of the
owner/operator of the application block
Respirators and other personal protective equipment (PPE) for handlers (handler task,
protective clothing, respirator type, respirator cartridge type, respirator cartridge replacement
schedule, eye protection, gloves, other PPE)
Emergency procedures (evacuation routes, locations of telephones, contact information for
first responders, local/state/federal contacts, key personnel and emergency
procedures/responsibilities in case of an incident, equipment/tarp/seal failure, odor
complaints or elevated air concentration levels outside buffer zone suggesting potential
problems, or other emergencies).
Posting procedures (name, address, and phone number of person(s) who will post signs,
location of posting signs, procedures for posting and sign removal)
Site-specific response and management (if applicable)
> Fumigant site monitoring
• Description of who, when, where, and procedures for monitoring buffer zone
perimeter
> Response information for neighbors
• List of residences, businesses, and neighboring property owners informed
• Name, address, and phone number of person doing notification
• Method of sharing information
State and tribal lead agency notification (If state and/or tribal lead agency requires notice,
provide a list of contacts that were notified and date notified.)
Plan describing how communication will take place between applicator, land owner/operator,
and other on-site handlers (e.g., tarp cutters/removers, irrigators) for complying with label
requirements (e.g., buffer zone location, buffer zone start/stop times, timing of tarp cutting
and removal, PPE).
> Name and phone number of persons contacted
> Date contacted
Authorized on-site personnel
> Names, addresses and phone numbers of all handlers
> Employer name, addresses, and phone numbers for all handlers
> Tasks that each handler is authorized and trained to perform
> Date of PPE training for each handler
> For handlers designated to wear respirators when respiratory protection is required
(minimum of one handler), date of medical qualification to wear a respirator and date of
fit testing for respirator.
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»«» Air monitoring
> For handlers without respiratory protection:
• If sensory irritation is experienced, indicate whether operations will be ceased or
operations will continue with respiratory protection
• If intend to cease operations when sensory irritation is experienced, provide the name,
address, and phone number of the handler that will perform monitoring activities
prior to operations resuming
> For handlers with respiratory protection:
• Representative handler tasks to be monitored
• Monitoring equipment to be used and timing of monitoring
*»* Good Agricultural Practices (GAPs)
> Description of applicable mandatory GAPs (registrants may also include optional GAPs)
> Measurements and other documentation planned to ensure GAPs are achieved (e.g.,
measurement of soil and other site conditions, tarp repair/perforating/removal plans)
*»* Description of hazard communication. (The buffer zone around the application block has
been posted in accordance with the label. Pesticide product labels and material safety data
sheets are on-site and readily available for employees to review.)
*»* Record keeping procedures (the owner/operator of the application block that he/she (as well
as the certified applicator) must keep a signed copy of the site-specific FMP and the post
application summary for 2 years from the date of application).
For situations where an initial FMP is developed and certain elements do not change for
multiple fumigation sites (e.g., applicator information, authorized on-site personnel, record
keeping procedures, emergency procedures) only elements that have changed need to be updated
in the site-specific FMP provided the following:
• The certified applicator supervising the application has verified that those elements are
current and applicable to the application block before it is fumigated and has documented
the verification in the site-specific FMP.
• Recordkeeping requirements are followed for the entire FMP (including elements that do
not change)
Once the application begins, the certified applicator must make a copy of the FMP
available for viewing by handlers involved in the fumigation. The certified applicator or the
owner/operator of the application block must provide a copy of the FMP to any federal, state,
tribal, or local enforcement personnel who request the FMP. In the case of an emergency, the
FMP must be made available when requested by federal/state/local emergency response and
enforcement personnel.
Within 30 days of completing the application portion of the fumigation process, the
certified applicator supervising the application must complete a post fumigation application
summary that describes any deviations from the FMP that have occurred, measurements taken to
comply with GAPs as well as any complaints and/or incidents that have been reported to
him/her. The summary must include the actual date of the application, application rate, and size
of application block fumigated.
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Specifically, the Post-Application Summary must contain the following elements:
»»» Actual date of the application, application rate, and size of application block fumigated
*»* Summary of weather conditions on the day of the application and during the 48-hour period
following the fumigant application
»»» Tarp damage and repair information (if applicable)
> Location and size of tarp damage
> Description of tarp/tarp seal/tarp equipment failure
> Date and time of tarp repair
»»» Tarp removal details (if applicable)
> Description of tarp removal (if different than in the FMP)
> Date tarps were cut
> Date tarps were removed
»»» Complaint details (if applicable)
> Person filing complaint (e.g., on-site handler, person off-site)
> If off-site person, name, address, and phone number of person filing complaint
> Description of control measures or emergency procedures followed after complaint
»»» Description of incidents, equipment failure, or other emergency and emergency procedures
followed (if applicable)
*»* Details of elevated air concentrations monitored on-site (if applicable)
> Location of elevated air concentration levels
> Description of control measures or emergency procedures followed
> Air monitoring results
• When sensory irritation experienced:
• Date and time of sensory irritation
• Handler task/activity
• Handler location where irritation was observed
• Resulting action (e.g., cease operations, continue operations with respiratory
protection)
• When using a direct read instrument:
• Sample date and time
• Handler task/activity
• Handler location
• Air concentration
• Sampling method
»»» Date of sign removal
»»» Any deviations from the FMP
In addition to recordkeeping requirements from 7 CFR part 110 "Recordkeeping
Requirements for Certified Applicators of Federally Restricted Use Pesticides", this decision
requires that both the applicator and owner/operator of the application block keep a signed copy
of the site-specific FMPs and the post-application summary record for 2 years from the date of
application.
• Applicators and other stakeholders have the flexibility to use EPA's templates, prepare
their own FMPs templates, or use other commercially available software with certain
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elements listed above in check-list and/or fill in the blank format. Below are examples of
other FMP templates available on the internet for structural fumigations that may be
useful to users when developing FMPs for metam-sodium and metam-potassium soil
applications:
• http ://www. cardinalproproducts. com/Mi sc/FMP%20 Version%203. pdf
• http://www.pestcon.com/techlibrary/fum mgmt_plan.doc
• http://www.agr.state.ne.us/division/bpi/pes/fumigation_plan.pdf
• http://www.agr.state.ne.us/division/bpi/pes/fumigation_plan2.pdf
• http://nmdaweb.nmsu.edu/pesticides/Management%20Plans%20Required%20for%20Fu
migations.html
The Agency has provided a template located in the appendix of this document.
4. Site Specific Response and Management
EPA believes measures for ensuring preparedness for situations when accidents or
emergencies occur are an important part of the suite of measures necessary to address risks posed
by fumigants. Therefore, EPA is requiring such measures at the community level in the form of
educational materials for first responders, and measures for specific sites to ensure early
detection and quick and appropriate response to situations as they arise.
Although EPA believes buffers and other mitigation will prevent many future incidents, it
is likely that some incidents will still occur due to accidents, errors, and/or unforeseen weather
conditions such as diurnal inversions. Early detection and appropriate response to accidental
chemical releases is an effective means of reducing risk, as well as addressing the source of the
release. Reducing risks associated with incidents that may occur in the future is a key part of
EPA's soil fumigant decisions. By combining buffers with GAPs, FMPs, and effective
emergency response, EPA is able to reach a "no unreasonable adverse effects" finding under
FIFRA.
To ensure that appropriate response mechanisms are in place in the event of a fumigant
exposure incident, EPA is requiring that registrants provide training information, in the context
of their community outreach and education programs to first responders in high-fumigant use
areas and areas with significant interface between communities and fumigated fields. In
addition, for situations in which people, homes, or other structures are in close proximity to
buffer zones, applicators must either monitor buffer zone perimeters or, alternatively, provide
emergency response information directly to neighbors. Each element is discussed in more detail
below.
First Responder Education
EPA is requiring registrants through their community outreach and education programs
(see the Community Outreach and Education Section), to ensure that emergency responders have
the training and information that they need to effectively identify and respond to fumigant
exposure incidents. EPA believes this will help ensure, in the case of a fumigant accident or
incident that first responders recognize the exposure as fumigant related and respond
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appropriately. Additional details are included in the Community Outreach and Education
Section of this document.
Emergency Preparedness and Response Considerations for the 2008 RED
Prior to the 2008 RED the EPA received comments from many stakeholders about the
Agency's emergency preparedness and response option. Users have commented that notification
is burdensome and that it is unnecessary if buffer zones are also required. However, community
groups have commented on the importance of bystanders being informed when fumigations are
occurring, since this group of pesticides, compared to other pesticides, has a greater potential to
move off site and affect people not involved in the application. State regulators have different
views on this requirement. Some support the sharing of information with neighbors, and some
states have notification requirements for fumigations with certain products or for certain
application methods. In addition, some states require notification to chemically sensitive
individuals in proximity to pesticide applications. Others also had concerns about the
enforceability of this type of measure and the possible burden on the states to enforce a
notification requirement.
California currently requires notification of persons within 300 feet of a methyl bromide
buffer zone. California strawberry growers consider the 300 foot notification area for methyl
bromide applications to be an extension of the buffer zone. In areas where a large number of
people would need to be notified about a planned methyl bromide application, strawberry
growers indicated that they would rather not use methyl bromide because some communities
could mobilize to prevent the fumigation from taking place. Some stakeholders also commented
that it would be protective and less burdensome if EPA required the user to monitor fumigant air
concentrations at the edge of the buffer for 24 hours after the application to ensure the fumigant
does not move beyond the buffer at concentrations that exceed EPA's level of concern. If
concentrations of concern were detected, the user would be required to implement the emergency
response measures specified in the fumigant management plan.
EPA has concluded that bystanders could take steps to protect themselves if they had
basic information about fumigations and the appropriate steps to take if they experienced
symptoms of exposure. In a number of fumigant incidents that have occurred, the magnitude and
severity of the incident could have been significantly reduced if people had such information.
Similarly, having on-site monitoring will enable site managers to take remedial action (i.e.,
activate the control plan in the FMP) to lower emissions sooner, also resulting in fewer and less
severe exposures. And, if necessary, site managers would activate the emergency response
elements of the FMP.
Providing communities with information about local chemical releases is an important
part of emergency preparedness programs and is recognized as an effective means of addressing
risk at the local level. Some states, like Florida and Wisconsin, have requirements for providing
information to chemically-sensitive individuals about chemicals used nearby so they can take
steps to protect themselves from potentially harmful exposures (see http://edis.ifas.ufl.edu/pi004
and http://www.legis.state.wi.us/rsb/code/atcp/atcp029.pdf). The requirements in Florida do not
apply to agricultural chemical applications. Wisconsin also requires fumigators applying metam-
sodium and metam-potassium products through chemigation to provide written notice to the
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county public health agency and to every individual or household within l/4 miles of the
chemigation application site (see http://www.legis.state.wi.us/rsb/code/atcp/atcp030.pdf). EPA
agrees that information about how to recognize and address exposures can help citizens reduce
potential risk.
EPA understands that difficult challenges exist when agricultural land borders urban or
suburban communities. While EPA's decisions for the fumigants will not alleviate challenges
that already exist, EPA is allowing options for ensuring emergency preparedness in an effort to
lessen potential impact on growers, while maintaining the Agency's protection goals.
EPA is not requiring a specific method of providing the information to neighbors, but
rather that it be done in a way that effectively communicates, in a manner the recipients will
understand. Some methods may not result in documentation that would be retained. To address
concerns about enforcement, EPA is requiring that information on how and when the emergency
response information was delivered, and to whom, be included in the FMP.
Emergency Preparedness and Response Revisions
To reduce risks to people who may be near a buffer zone (e.g., at their home or working
in a nearby field) in the July 2008 RED EPA required applicators to either monitor buffer zone
perimeters or, alternatively, provide emergency response information directly to neighbors. This
requirement is not dependent on people actually being present in the nearby buildings and
homes. In this respect it differs from the quarter/eighth mile buffer zone restriction on certain
types of occupied structures. Rather, this measure is intended to ensure protection in places
people may be found present. Whether measures are required depends on the size of the buffer
zone and how close land (e.g., residential properties and businesses) may be to the buffer zone.
The Agency received many comments about the Emergency Preparedness and Response
requirements that suggested the requirements were too complex and confusing. To address these
concerns, EPA has revised the structure and content of the requirements in the RED Amendment
to improve clarity. As was outlined in the 2008 RED., It is important to note that site-specific
Emergency Preparedness and Response measures are only required if there are people, homes or
businesses within a certain specified distance from the edge of the buffer zone.
Some comments were received that questioned the rationale behind scaling the
Emergency Preparedness and Response measures. EPA believes that scaling the size of the
Emergency Preparedness and Response area will be protective. Generally the larger the buffer
distance the higher the application rate or the size of the treated area may be, which translates to
a greater total amount of fumigant being applied and potentially higher exposure in the area
surrounding the application block. The buffer distances for triggering the Emergency
Preparedness and Response requirements are scaled to allow the amount of fumigant used (a
surrogate for potential exposure) determine the applicable distance for implementing this
requirement. When the area is scaled to the size of the buffer, small buffers which generally
result from applications to small areas, at low application rates, and/or using low-emission
application techniques, will have small or no areas to monitor or inform, while larger
applications will have larger areas to monitor or inform. In addition, to create additional
incentive to achieve the smallest buffer possible the EPA has included an exception for
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application blocks so fields with the smallest required buffers (25 feet) would not be subject to
this requirement, since they are most likely using lower application rates, applying to smaller
areas, and/or using better application methods. Based on changes to the buffer zone section
regarding overlapping buffer zones, any buffer zone that overlaps with another buffer zone must
use the maximum distance in the Emergency Preparedness and Response measures to determine
if monitoring or providing information to neighbors is needed. None of the other distances have
changed.
Many stakeholders also expressed concern over the potential burden the 2008 RED
requirements may have on applicators and growers. Specifically, the frequency and cost of
monitoring using sampling devices such as colorimetric tubes were of concern. Stakeholders felt
the inherent warning properties of chloropicrin and MITC (i.e., eye irritation) were better
indicators of exposure than available devices. Several of these comments noted concerns with the
reliability of such devices at low concentrations. Additionally, several stakeholders indicated
that monitoring is most appropriate and effective at dawn and dusk, the times of day when off-
site movement of concentrations is most likely. Based on these comments, the Agency has
revised the requirement so monitoring is required during those periods when risk of high
concentrations of fumigant moving beyond buffers is greatest (i.e., at dawn and dusk). As a
precaution, monitoring is also required once during the night and during the day.
Additionally, as noted above in the respiratory protection section of this document, due to
limitations on currently available technology for monitoring, use of sampling devices such as
colorimetric tubes will not be required at this time. EPA believes that currently available devices
are likely to be more reliable at fumigant concentrations which exceed EPA's action level
concentrations. In fact, some of these action levels are at or near the detection limits for the
devices available for some fumigants. Additionally, colorimetric devices provide snapshot
measurements. In conditions that are likely to be more static (e.g., monitoring an indoor
fumigation such as a grain mill or warehouse) it is likely that minute to minute changes in
conditions would not be as great as those anticipated for the more dynamic conditions
characteristic of outdoor field fumigation where exposure concentrations could shift because of
weather changes or stratification in soil conditions across a single field.
The Agency is modifying the procedures for monitoring buffer zones because of
technological limitations of currently available devices for MITC and chloropicrin that are not
practical or reliable for field use. However, the Agency does believe that quantitative air
monitoring would enhance safety if the appropriate technology were available as it is for methyl
bromide. Some equipment manufacturers have indicated interest in developing devices that
would be more functional and reliable for field fumigation applications (e.g., badge-type
monitors). EPA encourages such efforts and plans to stay abreast of developments and
improvements in monitoring devices and will consider this issue again in Registration Review or
sooner should such monitors become available in the short term. In the interim, buffer
monitoring for chloropicrin and the MITC generating chemicals will rely on sensory indicators
(e.g., eye and/or nose irritation) to trigger a response instead of using tubes. Monitoring tubes
are still required for measuring products that contain more than 80 % methyl bromide.
Finally some comments provided suggestions on how to increase flexibility in how a
grower may comply with these measures as well as the effectiveness of the option to provide
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information to neighbors. EPA agrees with the importance of users being able to comply with
these measures and has modified some aspects of the requirements for this option to reduce the
number of notices an applicator may need to provide to a given neighbor. Also, to enhance the
effectiveness of the information neighbors would receive, EPA is requiring that the information
is provided close to when the application is planned to take place and early enough for neighbors
to make use of the information. EPA believes these modifications will enhance compliance and
effectiveness of the information if the emergency response criteria are met and applicators
exercise this option.
Emergency Preparedness and Response Requirements
When are Emergency Preparedness and Response Measures Needed?
If the buffer zone is:
25 feet < Buffer < 100 feet
100 feet < Buffer < 200 feet
200 feet < Buffer < 300 feet
Buffer > 300 feet or buffer zones
overlap
AND There is land (e.g. residential properties
and businesses) NOT in the control of
the property operator within this
distance
from the edge of the buffer zone:
50 feet
100 feet
200 feet
300 feet
Then either monitoring of the buffer zone perimeter or providing emergency response
information to neighbors is required.
If the buffer zone is 25 feet, the minimal buffer zone size, then the Emergency
Preparedness and Response requirements are not applicable. Also, if all of the land within 300
feet of the edge of the buffer zone is under the control of the property operator, then no site
monitoring or informing neighbors would be required regardless of the size of the buffer zone.
Fumigation Site Monitoring
EPA has determined that monitoring of the buffer zone perimeter for fumigants moving
beyond buffers is an effective approach to protecting bystanders. Under this approach, if the
person monitoring the buffer perimeter experiences eye or nasal irritation, an early sign of
exposure to concentrations that exceed the Agency's action level, then the emergency response
plan specified in the FMP must be implemented. If other problems occur, such as a tarp coming
loose, then the appropriate control plan must be activated. Because data indicate that peak
concentrations sometimes occur on the second day following applications, and the greatest
potential for concentrations outside buffers may be observed at dawn and dusk, EPA has decided
that this monitoring must be done at least three times per day during the full buffer zone period at
dawn, dusk, and once once during the night and during the day, to ensure concentrations do not
exceed the action level which will be specified on product labels.
Specific requirements include:
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• Monitoring must take place beginning on the day the application begins until the buffer zone
period expires.
• Monitoring must be conducted by a certified applicator or someone under his/her supervision.
• Monitoring for air concentrations above the action level for the fumigant, as determined by
sensory irritation, must take place in areas between the buffer zone perimeter and residences
or other occupied areas that trigger this requirement.
• The person monitoring for perceptible levels must start monitoring approximately 1 hour
before sunset of the day the application begins and continue once during the night, once at 1
hour after sunrise, and once during the day until the end of the buffer zone period.
• If at any time the person monitoring the air concentrations experiences sensory irritation,
then the emergency response plan stated in the FMP must be immediately implemented.
• If other problems occur, such as a tarp coming loose, then the appropriate control plan must
be activated.
• The location and any results of the air monitoring must be recorded in the FMP.
While protective, this site monitoring might be burdensome for users fumigating in areas
with few people. Therefore, EPA is allowing users the alternative option of providing
emergency response information directly to neighbors.
Response Information for Neighbors
As an alternative to on-site monitoring, the certified applicator supervising the fumigation
(or someone under his/her direct supervision) would need to ensure that residences, businesses,
or other sites that meet the criteria outlined below have been provided the required information
below at least 1 week prior to the fumigant application in a specified field. If after 4 weeks, the
fumigation has not yet taken place, the information must be delivered again.
• Information that must be provided includes:
o The general location of the application block,
o Fumigant(s) applied including the active ingredient, name of the fumigant
products(s), and the EPA Registration number,
o Contact information for the applicator and property owner/operator,
o Time period in which the fumigation is planned to take place (must not range
more than 4 weeks),
o Early signs and symptoms of exposure to the fumigant(s) applied, what to do, and
what emergency responder phone number to call who to call if you believe you
are being exposed (911 in most cases), and.
o How to find additional information about fumigants.
The method for distributing information to neighbors must be described in the FMP and
may be accomplished through mail, telephone, door hangers, or through other methods that can
be reasonably expected to effectively inform people at residences and businesses within the
required distance from the edge of the buffer zone.
To clarify this measure, the following example is provided:
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• IF the buffer zone is 125 feet, then these requirements apply to residences within 100 feet of the
buffer zone. Either the applicator must monitor the area between the dotted house (they must monitor
where the black dot is) and the buffer zone or residents of the dotted house(?) [people within 100 feet
of the buffer zone] must be provided emergency response information.
• So the dotted houses would need to be informed, but the location of the cross-hatched house would
not prompt any action.
Figure 9. Example Site Map for Informing Neighbors.
100 ft
I
\
Buffer
zone T 125ft
Treated field
288ft
If there are no residences or other occupied structures within 300 feet of the edge of the
buffer zone, or if the buffer distance is the minimum of 25 feet, neither site monitoring nor
providing information to neighbors is required.
5. Notice to State Lead Agencies
Ensuring fumigant users understand and comply with the new label requirements is an
important component of the fumigant risk mitigation package since these requirements are
designed to mitigate risks of concern for bystanders, handlers, and workers. Knowledge of the
location and timing of fumigant applications allows enforcement officials to focus their
compliance assistance and inspection efforts around periods when, and places where,
fumigations are expected to occur. Therefore, in the July 2008 RED, the Agency required written
notification of the appropriate state or tribal lead agency prior to fumigant applications.
Following publication of the July 2008 REDs, the Agency received feedback from some
states that were interested in receiving the notice because it would enhance their ability to
provide technical assistance and assure compliance. However, the Agency also received
comments from states that were concerned about the notification requirement largely due to
resource constraints. Some states also indicated that they are already well-informed about when
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and where fumigations take place, and receiving specific notice of applications would create a
paperwork burden rather than aid their compliance assistance and assurance programs. Some
states recommended that, in lieu of receiving notice of fumigations, states could modify their
cooperative agreements with EPA to incorporate specific strategies for assuring compliance with
the new fumigant labels. States also suggested that rather than providing notice directly to states,
fumigators could enter application information into a registrant-developed and maintained
database. They suggested this would be an appropriate mechanism because it would standardize
and streamline the process for applicators to provide the required information, and states could
access and utilize information more quickly, with greater ease, and using fewer state resources.
Based on consideration of public comments, the Agency still believes that compliance
assistance and assurance is a critical component of the soil fumigant mitigation. EPA agrees that
some states already have mechanisms in place to provide them with information needed to assist
and assure compliance with new fumigant requirements, but other states are in need of additional
information to accomplish this objective. The Agency also believes that all states in which
fumigants are used will need to modify their cooperative agreements, to some extent, to
incorporate strategies for compliance assistance and assurance to aid the transition from current
labels to labels that reflect the new mitigation.
While the Agency will continue to work with all state and tribal lead agencies on efficient
ways to obtain the information needed to plan and implement compliance assistance and
assurance activities, the Agency is currently retaining the notification requirement only for state
and tribal lead agencies that choose to be notified of fumigant applications. The Agency plans
to provide a website listing these state and tribal lead agencies and how and when these agencies
want applicators to provide to them the following information:
o Applicator and property owner/operator contact information (name, telephone
number, and applicator license number)
o Location of the application block(s)
o Name of fumigant(s) products(s) applied including EPA Registration number
o Time period in which fumigation may occur
For states already requiring such information through an existing state process,
applicators will not be required to comply with this requirement. For example, the California
Department of Pesticide Regulation already obtains this information as part of their permitting
process for fumigant applications.
The Agency will work with all states to amend their cooperative agreements to include
strategies for compliance assistance and assurance, which will be particularly important over the
next several years as the new mitigation measures are implemented. For states that do not
choose to be notified of fumigant applications, modification of their cooperative agreements
must include the methods these agencies will use to survey fumigation application periods and
locations.
6. Training for Applicators and Training Information for Other Handlers
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Soil fumigation is an inherently complex activity involving specialized equipment and
application techniques. Additionally, the mitigation measures required as part of these decisions
will introduce new requirements in the form of more detailed instructions and restrictions on soil
fumigations. Failure to adequately manage fumigant applications increases risks to handlers
involved in the fumigation, nearby workers, and other bystanders. Incident data show that a
number of fumigant incidents are the result of misapplications, failure to follow label
requirements and other safety precautions, and other errors on the part of fumigant applicators.
Although states have certification programs, some of which include a specific category or
subcategory for soil fumigation, there currently is not a consistent standard across states and
regions where soil fumigation is done. Additionally, the federal certification program currently
has no category for soil fumigation, and while EPA is considering the development of a category
for soil fumigation, the potential changes to the federal certification program and worker safety
regulations to include a soil fumigation category are not anticipated in the near future.
EPA believes that training is an effective way to increase applicators' skill and
knowledge so they are better prepared to effectively manage the complexities and risks
associated with soil fumigation. Further, training is a means of ensuring fumigators are able to
understand and comply with revised fumigant labeling. Therefore, EPA determined that training
to establish a national baseline for safe fumigant use, developed and implemented by registrants,
will help enhance fumigators' ability to adequately manage the complexities of soil fumigation
and failure to comply with fumigant product labeling. EPA also determined that providing
additional safety information to other fumigant handlers will help them understand and adhere to
practices that will help handlers protect themselves from risks of exposure.
Soil Fumigation Training Considerations
In comments on fumigant risk management options, stakeholders were broadly
supportive of additional training for applicators and handlers. During the Phase 5 and post-RED
comment periods, the majority of stakeholders, including growers, community groups, farm
workers, states, and registrants expressed strong support for increased training for applicators
and other handlers. Several comments noted that fumigant incidents affecting both fumigant
workers and bystanders could have been prevented or mitigated if applicators had better training
about correct practices and procedures.
The Agency agrees that additional training for fumigant applicators and handlers will
help educate and inform these workers, thus decreasing the likelihood of both incidents and
noncompliance. EPA believes fumigant-specific training for applicators and additional training
information for handlers also will help reduce the magnitude and frequency of exposure
incidents and, coupled with the other mitigation measures described in this decision, will address
risks of unreasonable adverse effects from the use of soil fumigants.
It is important to note that training developed and provided by registrants as required by
this RED is separate and distinct from state certification programs. EPA encourages registrants,
in developing their training proposals, to work with states where their products are used to
identify opportunities to build on and complement state programs. However, the training
programs required as part of this decision are intended to be separate from the state certification
process and will be developed and administered by registrants. Individual state regulatory
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agencies have the option of working with registrants on these activities, but are not required to
do so. It is important to note that some fumigant registrants have already developed soil
fumigant training programs that will serve as a good basis for this expanded effort.
As noted above, several states have high-quality certification programs for fumigators
that include exams to test the competency of fumigators. EPA recognized that for applicators to
become certified in those states, they must acquire the knowledge and skill necessary to pass the
exam. But several stakeholders commented that training opportunities are varied across the
country, and the scope and detail of information provided in available training is not consistent.
EPA is also concerned that information in existing programs will need to be substantially
updated as a result of new requirements associated with this decision and the label changes
which will implement it. Although EPA is considering revisions to the federal certification and
training program in the future to include a soil fumigation category/subcategory, EPA believes
that registrants have access to resources and materials to best develop and deliver training in the
interim.
EPA stresses that registrant training programs will be separate from the state certification
process and will be developed and administered by registrants in coordination with EPA. EPA
will, however, work with state organizations and training experts to explore opportunities for the
registrant programs to supplement any existing state programs to provide additional training
resources for fumigators working in those states. EPA will also work with state lead agencies
and extension programs to review training program proposals, the content for the programs and
materials, and proposed vehicles for delivery.
During the post-RED comment period, the Agency received comments from several
states asking that the applicator training requirements be coordinated with existing state
certification and training programs. The Agency agrees that for states that have existing soil
fumigation certification programs that address the same training elements required of the
registrant soil fumigant training programs, as outlined in this section of the RED addendum,
applicators should be able to complete the state certification program in lieu of completing the
registrant soil fumigation training. For the state soil fumigation certification program to qualify,
both EPA and the state must agree that the program satisfies the applicator training elements
required in the RED.
Pesticide labels will state that the certified applicator supervising that application must
have successfully completed, within the last 36 months, a metam training program made
available by the registrant. The Fumigant Management Plan must document when and where the
training program was completed. This requirement for registrant-provided applicator training
does not supersede or fulfill state requirements, unless the state has expressly acknowledged that
the registrant training may substitute for state requirements
Training for Applicators Supervising Fumigations
The July 2008 RED required registrants to develop and implement training programs for
applicators in charge of soil fumigations on the proper use of and best management practices for
soil fumigants. This training would be required as a condition of use by product labeling.
During the public comment period on the proposed mitigation measures and the post-RED
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comment period, stakeholders were broadly supportive of additional training for fumigators, but
concerns were raised with regard to implementation of the training. The Agency also received
comments from state representatives and pesticide applicator training organizations, such as the
Association of American Pesticide Control Operators, Association of American Pesticide Safety
Educators, and Certification & Training Assessment Group, expressing concern over EPA's
decision to implement the training via labeling and raising questions over compliance and state
enforcement of such a requirement and the potential for conflict or redundancy with state
certification and training programs. Various stakeholders recommended that, rather than a label-
mandated training requirement, the Agency, instead, should require registrants to develop and
implement training for soil fumigant applicators as a condition of registration.
The Agency's goal in requiring soil fumigation training for applicators is to ensure that
all applicators in charge of soil fumigations understand the safe use of soil fumigants and in how
to apply products in compliance with new product labeling, including provision required by the
RED. Given the unique properties of soil fumigants and their application and safety procedures
compared with other agricultural and non-agricultural pest control practices, the inherent
complexities involved in soil fumigant applications, and the additional complexities that will
arise with the implementation of the REDs, the Agency feels that additional training, above and
beyond that available currently, will be needed. The states that currently have certification
programs that include soil fumigation categories will not have requirements pertaining to the
new mitigation and their programs will need to be modified. EPA agrees that making the
required training programs a condition of registration is an important means of ensuring that such
training is ultimately developed and implemented. However, it would not ensure that all
individuals in charge of soil fumigant applications avail themselves of the training. The Agency
believes that making successful completion of the training a condition of use is also important to
achieve this goal. Therefore, EPA has decided that development and delivery of training will be
a required in the DCI that accompanies this amended RED and successful completion of the
training will remain a condition of use.
Each registrant must develop and implement training programs for applicators in charge
of soil fumigations on the proper use of and best practices for soil fumigants. Registrants will be
required to submit proposals for these programs as data requirements that will accompany this
RED. EPA will review each program and determine whether it adequately addresses the
requirements specified in the DCI. The proposal must address, among other elements, both the
content and the format for delivering training. The Agency acknowledges the value of hands-on
training in the field, but recognizes that may not be feasible in all instances. The Agency
welcomes and is actively seeking participation from state lead agencies and extension programs
in the evaluation of the registrant training proposals and materials that are submitted.
The training programs must address, at a minimum, the following elements: (1) how to
correctly apply the fumigant, including how to comply with new label requirements; (2) how to
protect handlers and bystanders; (3) how to determine buffer zone distances; (4) how to develop
a FMP and complete the post-fumigation application summary; (5) how to determine when
weather and other site-specific factors are not favorable for fumigant application; and (6) how to
comply with required GAPs and how to document compliance with GAPs in the FMP. In
addition, based on comments received during the post-RED comment period, the Agency is
adding a seventh training element—training programs must also include information on how to
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develop and implement emergency response plans—to ensure that applicators are prepared in the
event that a problem develops during or shortly after the fumigant application. EPA is also
requiring registrants to incorporate a mechanism for evaluating the effectiveness of their training
programs at conveying the required information to participants and for determining whether
participants have successfully completed the training program.
To assist states in enforcing these training requirements, the registrants will be required to
(1) develop a database to track which certified applicators have successfully completed the
training, (2) make this database available to state and/or federal enforcement entities upon
request, and (3) provide documentation (e.g., a card) to each training participant who
successfully completes the training. This documentation shall include the applicator's name,
address, license number, and the date of completion. Applicators must provide to federal, state,
or local enforcement personnel, upon request, this documentation that verifies successful
completion of the appropriate training program(s).
In the July 2008 RED, the Agency required applicators supervising fumigations to
complete the training annually. During the post-RED public comment period, the Agency
received comments from various stakeholders indicating that the substance and content of
training would not change significantly from year to year, and that an annual training
requirement for applicators would be excessive and burdensome to both applicators and
registrants and was unnecessary. As a result of these comments, the Agency has decided to
require applicators supervising fumigations to have successfully completed the program within
the preceding 36 months and to document when and where the training program was completed
in their FMPs. This may be accomplished, for example, by simply attaching a copy of the
training documentation provided by the registrant to the FMP. The registrant also must be able
to provide to federal, state, or local enforcement personnel, upon request, the names, addresses,
and certified applicator license numbers of persons who successfully completed the training
program, as well as the date of completion.
Based on questions received during the post-RED comment period, the Agency is
clarifying that applicator training requirements are active ingredient-specific rather than product-
specific. That is, applicators who apply more than one of the soil fumigant active ingredients
(i.e., methyl bromide, chloropicrin, metam-sodium, metam-potassium, or dazomet) will be
required to complete training for each soil fumigant active ingredient they apply, but not for each
different product containing the same active ingredient(s). Further, EPA encourages the soil
fumigant registrants to jointly develop programs to reduce the redundancy of this training
requirement. For example, a substantial portion of the required training is universal to all soil
fumigants. Therefore modules addressing the information common to all could be generic and
each fumigator would participate in those modules, while separate modules addressing active
ingredient-specific content could be provided to those fumigators supervising applications with
those active ingredients only. Documentation provided to trainees could indicate the active
ingredient modules completed. While EPA sees efficiencies in such an approach, it will be the
registrants' choice as to how they will comply with the requirement to develop and implement
training programs.
Training Materials for Handlers
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EPA is requiring registrants to prepare and disseminate training information and
materials for other fumigant handlers, i.e., those working under the supervision of the certified
applicator in charge of fumigations. The Agency is requiring registrants to submit proposals for
these materials through the data call-ins that will accompany this RED. EPA will review these
materials to determine whether they adequately address the requirements specified in the DCI.
The Agency welcomes and is actively seeking participation from state lead agencies and
extension programs in the evaluation of these handler training materials.
The training materials must address, at minimum, the following elements: (1) what
fumigants are and how they work, (2) safe application and handling of soil fumigants, (3) air
monitoring and respiratory protection requirements for handlers, (4) early signs and symptoms of
exposure, (5) appropriate steps to take to mitigate exposures, (6) what to do in case of an
emergency, and (7) how to report incidents. Registrants must provide this training information
through channels open to the public (e.g., via a website). Pesticide labels will require that
applicators supervising fumigations provide this training information to handlers under their
supervision before they perform any fumigant handling task, or they must ensure that handlers
have been provided the required information within the preceding 12 months. The label will also
require that the training information be provided in a manner that the handler can understand.
Applicators supervising fumigations must ensure the FMP includes how and when the required
training information was provided to the handlers under their supervision.
"The certified applicator must provide fumigant safe handling information to each handler
involved in the application in a manner that they can understand prior to performing any
fumigant handling task or confirm that each handler participating in the application has received
fumigant safe handling information in the past 12 months."
During the post-RED comment period, no substantive comments were received that
resulted in changes to the RED requirements for training materials for handlers, as a result, these
requirements are identical to those published in the July 2008 RED. However, during the
comment period, the Agency received comments indicating that there was some confusion about
whether fumigant handlers working under the supervision of the certified applicator would be
required to be trained, i.e., participate in a training program developed by the soil fumigant
registrant(s), or whether handlers would need only to be provided with training information and
materials. The Agency wishes to clarify that handler participation in a registrant training
program, per se, is not required. As noted above, applicators supervising a soil fumigation will
be required to provide the registrant-developed, EPA-approved training information to handlers
in a manner that they can understand prior to performing any fumigant handling task, or
applicators must ensure that the handler has been provided the required information within the
proceeding 12 months.
7. Community Outreach and Education Program
EPA understands from public comments, site visits, and stakeholder meetings, conducted
as part of the soil fumigant review, that there is often a fundamental lack of information and
communication about soil fumigants within communities where soil fumigation occurs, which
has raised health and safety concerns among community members. This lack of information and
communication has led to inappropriate responses in cases where fumigants have moved off site
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and into communities. This also has led, in some cases, to unwarranted concern and anxiety
among communities about the risks associated with the use of fumigants. The Agency believes
that outreach and education to communities where soil fumigation occurs is an important
component of the overall package of measures to address bystander risk. Community outreach
will address the risk of acute bystander exposure by informing community members in high-use
areas about buffer zones and their characteristics and purpose, the meaning of posted warning
signs, the importance of not entering buffer zones, how to recognize early signs of fumigant
exposure, and how to respond appropriately in case of an incident.
In the July 2008 RED, the Agency required registrants to develop and implement
community outreach and education programs to address these needs. At a minimum, these
programs were to include the following elements: (1) what soil fumigants are and how they
work, (2) what buffer zones are, (3) early signs and symptoms of exposure, (4) appropriate steps
to take to mitigate exposures, (5) what to do in case of an emergency, and (6) how to report an
incident as well as a plan for evaluating the effectiveness of these programs. Few details on how
the programs would be implemented were provided in the RED. Rather, during the post-RED
comment period, the Agency sought feedback from the registrants and other stakeholders on how
best to design and target programs to community members in high-use areas. The Agency
encouraged the registrants to work with existing community resources, such as community
health networks, for disseminating information and implementing community outreach
programs.
During the post-RED comment period, the Agency received some comments from
stakeholders that suggested that having registrants develop and implement a community outreach
and education program is unnecessary and likely to needlessly raise heath and safety concerns
among community members, and such a requirement could draw scarce resources from other
registrant stewardship efforts. As noted previously, the Agency believes that providing basic
information about soil fumigants and buffer zones as well as information on what to do in the
event that an incident occurs to communities in high fumigant use areas is an important
component of the overall package of risk mitigation measures to address bystander risk. EPA's
community outreach requirements do not preclude other voluntary stewardship programs or
activities targeted to community members or the applicator/grower community, but rather are
meant to help ensure that community members in high fumigant usage areas are informed about
soil fumigant safety and better able to respond appropriately if an incident were to occur.
Few recommendations and no specific proposals for these programs were received during
the post-RED comment period. Therefore, the Agency is identifying minimum requirements that
each registrant must fulfill when developing its community outreach programs in response to a
DCI that will be issued. The Agency remains open to considering additional registrant outreach
program elements that address the same needs and goals as the program requirements described
below in their response to the DCI. EPA notes that registrants have suggested that programs
focusing on specific target audiences, such as staff and managers of migrant health care and day
care facilities, prison officials, and school nurses and principals, may be more effective in
providing useful information in a meaningful way than broadcast messages to entire
communities. Registrants have indicated that they will provide proposals for such programs in
late May 2009. EPA looks forward to these proposals and will consider the extent to which they
contribute to meeting the goals of the community outreach programs required by the RED.
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In the absence of acceptable alternative proposals, registrants, will be required to provide
information to the communities in the form of monthly public service announcements (PSAs)
distributed via local radio stations or newspapers in high-use fumigant areas during the
fumigation season(s) in those areas. As per the requirements included in the July 2008 RED, at a
minimum, registrants must include the following information in their community outreach
messages: (1) what soil fumigants are and how they work, (2) what buffer zones are, (3) early
signs and symptoms of exposure to MITC, (4) appropriate steps to take to mitigate exposures to
MITC, (5) what to do in case of an emergency, and (6) how to report an incident as well as a
plan for evaluating the effectiveness of these programs. Based on comments, EPA has decided
that information on the meaning of posted warning signs is also important to help ensure the
signs convey the needed information about the importance of staying out of buffer zones and
treated areas.
The Agency is requiring registrants to implement their outreach programs in communities
located in areas where there is high soil fumigant use. For the purposes of the RED addendum,
high-use areas are considered at the county level. To identify these areas, the Agency is
proposing the process for identifying high-use areas in the subsection following the section on
information for first responders. However, the Agency is willing to consider alternative
proposals for identifying high soil fumigant-use areas, based on additional data sources and
alternate approaches identified by the registrant(s) and other stakeholders.
Information for First Responders
In the July 2008 RED, the Agency required registrants to ensure that first responders in
areas with high fumigant usage have the training and information that they need to effectively
identify and respond to fumigant exposure incidents. Specifically, the registrants were required
to provide information and/or training to first responders, which at a minimum, included the
following elements: (1) how to recognize the early signs and symptoms of fumigant exposure,
(2) how to treat fumigant exposures, and (3) how fumigant exposure differs from other pesticide
exposure. In addition, the registrants were required to provide material safety data sheets to first
responders for both the fumigant applied (e.g., metam-sodium and metam-potassium) as well as
the active compound generated (e.g., MITC). Few details on how the education programs would
be implemented were provided in the RED. Rather, during the post-RED comment period, the
Agency sought feedback from the registrants and other stakeholders on how best to design and
target programs to first responders in high-use areas. The Agency encouraged the registrants to
work with state and local emergency response coordinators to identify needs and opportunities to
supplement any information already included in state and local training for first responders about
soil fumigants specifically.
During the post-RED comment period, the Agency received comments from several
registrants indicating that rather than requiring registrants to implement face-to-face training
programs, the Agency should consider allowing the required first responder training information
to be conveyed via written materials to state and local emergency response agencies, which
would provide these agencies the ability to incorporate this information into their existing
training programs. Other comments indicated that even if training programs were developed, it
would be difficult to ensure participation of first responders. The Agency's goal for the first
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responder training program is to ensure that first responders in high use fumigant areas have
access to the information that they need to be able to quickly and effectively identify an exposure
that is fumigant related and respond appropriately. The Agency agrees that this goal can be met
by requiring the soil fumigant registrants to develop informational materials on the soil
fumigants and distribute this information to first responders (i.e., police, fire, rescue, emergency
medical services, and others who respond to "911" calls) in high soil fumigant-use areas. This
would then provide the first responder entities the ability to incorporate this information into
their existing first responder training programs as they best see fit. This recommendation has
been incorporated into the RED amendments for the soil fumigants.
The Agency is willing to consider additional registrant proposals so long as they address
the same needs and achieve the same goals as the program requirements described below. At a
minimum, registrants will be required to develop and disseminate chemical-specific soil
fumigant training materials to first responders i.e., police, fire, rescue, emergency medical
services, and others who respond to "911" calls) operating in high fumigant-use areas. As a data
requirement in the DCIs that will accompany the REDs, registrants must submit proposals
detailing how they will (1) identify the first responder entities in high soil fumigant-use areas to
which they will disseminate the training materials, and (2) provide materials to the first
responders in these areas. Additionally registrants must provide draft copies of the training
materials for EPA review and approval. As per the requirements included in the July 2008 RED,
at a minimum, the materials must convey the following information to first responders: (1) how
to recognize the early signs and symptoms of metam-sodium or metam-potassium fumigant
exposure, (2) how to treat metam-sodium or metam-potassium fumigant exposures, and (3) how
("x" chemical) fumigant exposures differ from other pesticide exposures as well as (4) copies of
material safety data sheet(s) for the fumigant applied as well as for the active compound
generated, if applicable. Training materials can take a number of forms, including: brochures,
fact sheets, CDs, videos, web-based training materials, etc., as long as these materials
incorporate, at a minimum, the information requirements identified above.
The Agency is requiring registrants to target their first responder training information to
those communities located in high soil fumigant-use areas. For the purposes of the RED, high-
use areas are considered at the county level. To identify these areas, the Agency is proposing the
following process. However, the Agency is willing to consider alternative proposals in the
registrants' response to the DCIs for identifying and targeting high-use soil fumigant areas, based
on additional data sources and alternate approaches identified by the registrant(s).
Process for Identifying High-Use Fumigant Areas:
Identifying high-use areas for metam-sodium and metam-potassium is a two-step process
because reliable fumigant use data is not available at the county level from either publicly
available data sources or EPA proprietary data sources. First, the states with high use of metam-
sodium and metam-potassium have been identified by the Agency using EPA proprietary data.
[Although state-level data are available from USDA's National Agricultural Statistics Service
(NASS), EPA proprietary data are more robust.] Second, the high-use counties for metam-
sodium and metam-potassium within those states must be identified. The second step, identifying
high-use counties, will be the registrant's responsibility, using the process defined below.
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• Step 1: Identifying States with High Use of Metam-Soidum and Metam-Potassium: The
Agency is defining states with high usage of metam-sodium and metam-potassium as
those states where, on average, more than 100,000 Ibs of metam-sodium and metam-
potassium are applied annually. To determine those states where, on average, more than
100,000 Ibs of metam-sodium and metam-potassium has been applied annually, the
Agency obtained data on the average number of pounds of metam-sodium and metam-
potassium applied in all states across a ten-year period (1999-2008) using EPA
proprietary data. To view the Agency's analysis of this data, please see the Biological and
Economic Analysis Division's memo, "Process for Defining High-Use Fumigant Areas at
State and County Levels" dated May 14, 2009 and supporting documentation located in
the metam-sodium and metam-potassium docket at EPA-HQ-OPP-2005-0128.
• Step 2: Identifying Counties with High Use of Metam-Sodium and Metam-Potassium:
For each of the high-use states that the Agency identified in Step 1, the registrants will be
required to identify the counties where use of metam-sodium and metam-potassium may
be high. Because county-level fumigant usage data is not publicly available and EPA
proprietary data are not reliable, crop acreage should be used as a surrogate indicator for
fumigant usage. Crop acreage can be obtained for major use sites of metam-sodium and
metam-potassium from the publicly available 2007 USDA Census of Agriculture. Crop
acreages for each of the major use sites for metam-sodium and metam-potassium should
be obtained for each the major use sites for metam-sodium and metam-potassium and
then summed by county. All counties making up at least the top 90% of acreage in a state
are considered high-use areas. Registrants will be required to target each of these high-
use counties for community outreach programs.
For the purposes of this analysis, the Agency defines a "major use site" as any crop that
has more than 5% crop treated annually or more than 1,000,000 Ib of metam-sodium and
metam-potassium applied annually.
Example Identifying High-Use Fumigant Areas for Metam Sodium andMetam-Potassium in
California:
To help explain the process for identifying high-use fumigant areas for metam-sodium
and metam-potassium the Agency is providing the following example, which identifies the high-
use counties for the soil fumigant, metam-sodium and metam-potassium, usage in California.
• Step 1: Identify States with High Use of Metam-Sodium and Metam-Potassiunr
o Based on its analysis of proprietary data, the Agency has identified the following
high-use states for metam: California, Washington, Idaho, Oregon, Wisconsin,
Michigan, Florida, Minnesota, North Carolina, Virginia, Arizona, Nevada,
Georgia, Colorado, and North Dakota. This example will focus only on
identifying the counties in California with high use of metam. The same process
would be applied to other high-use states.
• Step 2: Identify the Counties in California with High Use of Metam-Sodium and Metam-
Potassium:
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o EPA has identified the following as the major use sites of metam-soidum and
metam-potassium: artichokes, cabbage, cantaloupes, carrots, onions, peanuts,
peppers, potatoes, spinach, squash, tomatoes, and watermelons.
o Using the 2007 USDA Census of Agriculture, registrants will need to obtain
harvested crop acreage data for each of the 12 major use sites for metam
identified above for each county in California. (An example of this analysis is
provided as a supporting document to the Biological and Economic Analysis
Division's memo "Process for Defining High-Use Fumigant Areas at State and
County Levels" dated May 14, 2009 which is located in the metam-sodium and
metam-potassium docket atEPA-HQ-OPP-2005-0125.
o Registrants will then need to sum the total number of combined crop acres for
these major use sites for each county in California and then select all the counties
that make up at least the top 90% of acreage in the county. [An example of this
analysis is also provided as a supporting document to the Biological and
Economic Analysis Division's memo "Process for Defining High-Use Fumigant
Areas at State and County Levels" dated May 14, 2009 which is located in the
metam-sodium and metam-potassium docket atEPA-HQ-OPP-2005-0125.]
As with the training for fumigant applicators and handlers and the community outreach
program that the Agency is requiring, the first responder training requirements are intended to be
part of the registrants' long-term product stewardship. The Agency encourages registrants to
work with appropriate state emergency response entities in these areas to ensure that the
appropriate first responder entities are being targeted and that the information being provided to
first responders is both useful and presented appropriately.
8. Ambient Air Monitoring Program
In the July 2008 Metam-Sodium and Metam-Potassium RED, the Agency required the
registrants to develop an air monitoring program in high-use areas to evaluate whether ambient
air concentrations exceed EPA's level of concern and help the Agency to determine whether the
RED mitigation measures are adequately protective of bystanders and decide whether additional
risk management measures are warranted.
During the post-RED comment period, the Agency received 2008 ambient air monitoring
data for MITC in Southern Franklin County, Washington, from the Washington State University
(WSU) Food and Environmental Quality Lab (FEQL) ["2008 MITC Residential Community Air
Assessment: Franklin County, Washington" (LePage and Goss 2008); MRID 47732802].
Agency analysis of ambient air data collected by WSU-FEQL in Southern Franklin County,
Washington in 2005, 2007, and 2008 show exceedances of the Agency's level of concern for
MITC (MOE < 10) at two monitoring stations in the fall of 2008. Agency analysis of ambient air
data for MITC in California from 1997-2001 developed by the California Air Resources Board
(CARB) identified exceedances of the Agency's short- and intermediate-term levels of concern
(MOE < 30) at three sample locations (indoor and outdoor) in Bakersfield, California, in the
summer of 1997. In addition, the Agency is aware of a number of on-going ambient monitoring
efforts going on in certain parts of the country including California and the Pacific Northwest.
(For additional information on the Agency's analysis of both the WSU-FEQL and CARB
ambient air monitoring data, please see "Metam Sodium: Third Revision of the HED Human
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Health Risk Assessment, DP# 293354 located in the metam-sodium and metam-potassium
docket at: EPA-HQ-OPP-2005-0125.) The Agency is also concerned about chronic exposures
and is seeking additional toxicity data on the long-term effects from inhalation exposure to
MITC. However, none of the available ambient air studies conducted so far adequately reflects
potential long-term concentrations of MITC.
As part of the RED, the Agency is implementing a number of mitigation measures
designed to reduce air concentrations of MITC. To help the Agency to determine if these
mitigation measures are adequately protective of bystanders and to decide whether additional
risk management measures are warranted, the Agency is requiring registrants to conduct ambient
air monitoring programs in six counties in the United States with the highest usage of metam-
sodium and metam-potassium, as identified in EPA's analysis to identify high-use areas for
implementing their community outreach and first responder training programs (see the
Community Outreach Program and First Responder Education sections for details). Registrants
are required to develop air monitoring programs that will enable the Agency to evaluate both: (1)
potential maximum peak air concentrations in areas of high seasonal use and (2) potential
community-level chronic air concentrations in areas of high metam-sodium and metam-
potassium use. The air monitoring should begin in 2010 and continue thru the 2011 and 2012
application seasons. This data will allow the Agency to evaluate whether the package of
mitigation measures, including buffer zones, have effectively reduced ambient air concentrations
and will be included in the reevaluation for metam-sodium and metam-potassium in registration
review. EPA encourages the registrants to work with existing air monitoring programs such as in
CA and WA or the registrants may develop their own program. The registrant's proposal for
developing and implementing an air monitoring program will be required as a data requirement
in the data call-in. Proposals should identify the six high use counties where ambient air
monitoring will take place. EPA will review these proposals to determine whether they
adequately address the requirements specified in the DCI.
Environmental Risk Management
In the July 2008 RED, EPA addressed the concerns about both aquatic and terrestrial
risks which are discussed in Section III.C. The July 2008 RED also stated that EPA believed
that mitigation measures detailed in the Human Health Risk Mitigation Section would also
reduce ecological risks. The Agency stated that although buffer zones and GAPs do not directly
reduce the potential risk to ecological organisms, these mitigation measures do provide an
incentive to reduce fumigant application rates and individual treatment areas which in turn will
contribute to lower exposure and risks for non-target organisms.
The July 2008 RED discussed exposure to terrestrial organisms, such as birds and
mammals, which could occur via inhalation of MITC. Potential exposure to aquatic
invertebrates and fish may occur from surface runoff/leaching and drift (wind) of MITC.
A species-specific analysis for the California Red-Legged Frog case has been conducted
for metam-sodium and metam-potassium and it major degradate, MITC. The Agency
determined that MITC "May-Affect" this species. The Agency's assessment is currently with
the Services (i.e., the U.S. Fish and Wildlife Service and the National Marine Fisheries Service).
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After the final determination has been made, the Agency may require other mitigation.
The July 2008 RED also discussed uncertainty associated with potential risk to non-target
plants, given that there are no data available. Additional plant toxicity data for MITC is being
required.
The July 2008 RED noted that based on the fate parameters of MITC, it should not
persist in terrestrial environments because of volatilization and degradation and the available
non-targeted monitoring data does not detect MITC in the ground-water samples within the U.S.
However, MITC is highly soluble in water and has a low adsorption to soil which suggests that
there is a potential of leaching to shallow groundwater under flooded and saturated conditions.
Also, if intense rainfall or continuous irrigation occurs there is potential for MITC to move to
surface water. Due to the importance of adequate soil moisture as described in the GAP section
and the knowledge that volatilization is metam-sodium and metam-potassium's most important
route of dissipation, EPA required the following language in the July 2008 RED taking these
factors into consideration: "While metam-sodium, metam-postassium, and their major degradate
MITC have certain properties and characteristics in common with chemicals that have been
detected in groundwater (MITC is highly soluble in water and has low adsorption to soil),
volatilization is this chemical's most important route of dissipation."
While the Agency believes that volatilization is this chemical's most important route of
dissipation, it is being removed from the groundwater statement because volatilization is
addressed in other areas of the mitigation package. The new language will state, "Metam-
sodium, metam-potassium and their major degradate MITC have certain properties and
characteristics in common with chemicals that have been detected in groundwater (MITC is
highly soluble in water and has low adsorption to soil)."
The July 2008 RED also included language required for both tarped and non-tarped
metam-sodium and metam-potassium applications to minimize potential for leaching. During
the post-RED comment period commenters stated that the following language was not clear or
enforceable: "For untarped applications of metam-sodium and metam-potassium, potential
leaching into groundwater and runoff into surface water can be reduced by avoiding applications
when heavy rainfall is forecasted to occur within 24 hours."
EPA would like to clarify that the statement was meant to be advisory and not
mandatory. However in an effort to clarify the requirement the Agency has revised the July
2008 RED language as follows, "For untarped applications, leaching and runoff may occur if
there is heavy rainfall after soil fumigation." The revised statement is based on information
presented in a 2007 article by Zhang and Wang12.
Please see section V of this document for the revised ground water label statements.
b. Sewer Root Control Use
12 Zhang, Y. and Wang, D .2007. Emission, distribution, and leaching of methyl
isothiocyanate and chloropicrin under different surface containments.
Chemosphere, 2007 Jun; 68(3): 445-454.
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During the post-RED comment period, the Agency received additional usage and
occupational exposure information from the two metam-sodium sewer use registrants, Sewer
Sciences, Inc. and Douglas Products and Packaging Company, which allowed the Agency to
refine the metam-sodium non-cancer (i.e., short-term and intermediate-term) and cancer sewer
use risk estimates. (To view the revised metam-sodium human health risk assessment, which
incorporates the revised sewer use risk estimates, please see: Metam Sodium: Third Revision of
the HED Human Health Risk Assessment, 04/30/09, D357118 in the metam-sodium docket at
EPA-HQ-OPP-2005-0125.) The comments specifically focused on the inputs of application rate,
the amount of product handled per day, the amount of time applicators may be exposed during a
work day, and the typical number of days per year that metam-sodium is used. A short summary
of the information provided and an explanation of how it was used by the Agency in revising it
risk assessment is summarized below.
• Application Rate: The Agency revised the application rate used in the 2008 RED
calculations (0.212 Ib ai/A) based on typical application rate data submitted by Douglas
Products and Packaging (0.111 Ib ai/A) for Sanafoam Vaporooter II (EPA Registration
No. 1015-70) and the application rate information listed on Sewer Science Inc.'s product,
Rout, label (EPA Registration No. 64898-4) (0.127 Ib ai/A). Both application rates were
considered in the revised human health risk assessment.
• Amount of Metam-Sodium Handled Daily: Sewer Sciences Inc. reported that their
applicators treat between 4,500 and a maximum of 10,000 feet of sewer pipe (8"
diameter) in a day, which corresponds to between 600 and 1,333 gallons of metam-
sodium handled per day. Douglas Products and Packaging reported that their applicators
treat between 2000 and 4000 linear feet of sewer pipe (8" diameter) daily, which
corresponds to between 250 and 500 gallons of metam-sodium handled per day. The
Agency utilized both exposure estimates in its revised human health risk assessment.
• Exposure - Number of Days Workers Treat Sewers Each Year: Based on an analysis of
its sales data, Douglas Products reported that workers apply metam-sodium to sewers a
maximum of 160 days per year. Sewer Sciences reports that applicators apply their
products approximately 220 days per year. Both exposure scenarios were considered in
the revised human health risk assessment.
• Exposure - Number of Hours Exposed to Metam-Sodium Each Day: Sewer Sciences Inc.
has reported that commercial applicators work with metam-sodium 8 hours each day and,
therefore, metam-sodium worker exposures should be estimated at 8 hours daily. The
comments submitted by Douglas Products and Packaging reported that the time per day
that metam-sodium exposure can occur is limited to the amount of time actually spent
loading the chemical and the time when the applicator hose is removed from the sewer
manhole. Most of the application time consists of the hose being unrolled into the
manhole cover and then rolled out of the manhole cover. Therefore, there is no potential
for exposure to metam-sodium during most of the application time. Based on the usage
and exposure information submitted by Douglas Products and Packaging, the Agency
believes that it is appropriate to assume two hours of exposure to metam-sodium in its
cancer assessments, since the duration of exposure to metam-sodium is limited.
During the public comment period, the Agency also received information from Douglas
Products indicating that closed engineering systems are employed for all mixing and loading
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activities. As a result, EPA is requiring closed mixing loading systems for all metam-sodium
sewer use applications to limit exposures to handlers.
In a February 2009 letter received from a representative on behalf of the registrant, Sewer
Sciences Inc., the company provided data identifying the sewer use of metam-sodium as a source
of N-nitrosodiumethylamine (NDMA) in wastewater and asked the Agency to consider this
information in its assessment of the use of metam-sodium in sewers. In the Agency's "Revised
Environmental Fate and Ecological Effects Risk Assessment for Metam-sodium and Metam-
potassium" (PC Codes 039003 and 039002; DP Barcode D293339) (see the metam-sodium
docket at: EPA-HQ-OPP-2004-0159-0118), the Agency acknowledged NDMA, for which there
is a National Recommended Water Quality Criteria of 0.00069 ug/L (current/potential drinking
water) and 3.0 ug/L (no potential for drinking water), as a reported contaminant in metam-
sodium sewer use products. To further evaluate metam-sodium sewer use as a potential source
for NDMA in wastewater, the Agency will require the registrants, in response to the product-
specific data call-in (pDCI) that will accompany this RED addendum, to report to the Agency
any concentration of NDMA in their product(s), pursuant to FIFRA Section 158.350(a)(4).
Based on comments received during the post-RED comment period the Agency is
providing additional characterization or the dermal risks from metam-sodium and the inhalation
risks from both metam-sodium and MITC. Additionally, comments received from Sewer
Sciences, Inc. identified errors that had been made in July 2008 RED which included
noncommercial handler cancer risks, representing five days of exposure, rather than the
commercial handler cancer risks, which were represented by 220 days of exposure and
presenting cancer risk from dermal exposures to metam-sodium when an OV respirator is worn.
In their comments, Sewer Sciences Inc. correctly noted that if the cancer risks are derived from
dermal exposure, a respirator would not be an effective means of mitigating these risks.
Rationale
Metam Sodium Non-Cancer Occupational Risk Concerns - Acute & Short-term Inhalation
Risks from MITC Exposure
Because metam-sodium degrades rather quickly to MITC, short-term, intermediate-term,
and chronic inhalation exposures to metam-sodium by workers are expected to be negligible
when compared with MITC exposures. To assess acute and short-term inhalation risks to
applicators, EPA utilized two studies, conducted in Australia, which measured MITC air
concentration levels during application of a metam-sodium product to sewers. These studies
represent the best available acute- and short-term MITC inhalation exposure data. Table 12
below summarizes the acute and short-term MOE estimates for MITC inhalation exposure to
handlers based on exposure levels from these studies. Estimates represent baseline conditions as
well as the use of dermal or respiratory protection, as indicated.
Table 12. Handler MOEs for MITC Inhalation Exposure from
Sewer Use Application of Metam-Sodium
Study
Sample
MITC
Cone.
(ppm)
Baseline MOEs
Acute
ST
PF 10 Respirator
MOEs
Acute
ST
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Sheers R (1994)
Melbourne Water -
Sanafoam
Vaporooter Trial, 7
November 1994
Sheers R (1995)
Melbourne Water -
Sanafoam
Vaporooter Trial,
13-14 February
1995, ICI Australia
Operations Pty
Ltd.
Operator breathing zone exposure
At point of application
Two manholes downstream (approx. 300 m)
At point of application - 24 hours post-application
Operator breathing zone exposure
Operator breathing zone exposure
Operator breathing zone exposure
At point of application - 30 mins post application
At point of application - 90 mins post application
At point of application - 180 mins post application
At point of application - 270 mins post application
At point of application - 360 mins post application
At point of application - 24 hours post-application
0.27
22
0.017
0.023
< 0.017
< 0.027
0.057
2.6
1.3
6.8
4.4
0.87
< 0.010
MOE1
1
<1
36
26
13
8
4
<1
<1
<1
<1
1
60
MOE2
1
na
na
na
10
7
3
na3
na3
na3
na3
na3
na3
MOE1
10
9-10
360
260
130
80
40
9-10
9-10
9-10
9-10
10
600
MOE2
10
na
na
na
100
70
30
na3
na3
na3
na3
na3
na3
1 Acute MOEs for breathing zones samples based on NOAEL of 0.22 ppm. For other samples (less than 15 minutes)
acute MOEs based on 0.60 ppm. Acute target MOE = 10.
2 MOEs were not estimated for static measure measurements. Short-term target MOE = 30.
3 na = not available
These estimates indicate that for samples taken in the breathing zone of the applicator,
the target MITC concentrations ranged from 0.27 ppm to < 0.017 ppm, with acute MOEs ranging
from 1 to 13 and short-term MOEs ranging from 1 to 10. While these MOEs are below both the
target MOE of 10 for acute inhalation exposures to MITC and the target MOE of 30 for short-
term exposures to MITC, as noted previously, these estimates do not take into account the use of
respiratory protection. Samples taken at the point of application (i.e., directly over a manhole
where a metam-sodium application had taken place, both immediately after an application and at
regular intervals in time after an application had taken place), were largely below an MOE of 1.
To address the short- and intermediate-term MITC inhalation risks from MITC, in the July 2008
metam-sodium metam-potassium RED, the Agency required that any person(s) engaged in any
activities that are likely to involve direct contact with metam-sodium (including, but not limited
to, mixing, loading, and/or applying metam-sodium; equipment calibration; cleaning and repair
of application equipment; entering into treated areas; sampling cleanup spills; and rinsate
disposal) wear a half-face respirator with organic vapor cartridge approved for MITC.
While there is insufficient toxicological data to characterize the inhalation cancer risk of
MITC, due to limitations in the rat and mouse MITC oral carcinogenicity studies, the Agency
anticipates that these new respiratory requirements will adequately address this risk. However,
the Agency is requiring additional study data (see Section V), including: (1) an inhalation
development toxicity rat study (GLN 870.3550), (2) a two-generation inhalation reproduction
study in rat (GLN 870.3800), and (3) carcinogenicity studies (i.e., rat and mouse) for MITC
(GLN 870.4200). In addition, to understand the ratio of the conversion of metam-sodium to
MITC, the Agency is adding a requirement for monitoring data in the breathing zone of the
mixer/loader/applicator for sewer use metam-sodium applicators (GLN 875.1300) This study
should measure dermal exposure to metam-sodium and inhalation exposure to MITC to
determine what handlers are being exposed to and in what quantities. This MITC monitoring
data, in addition to the data being requested to characterize the inhalation cancer risk of MITC,
will enable the Agency to further characterize the toxicity profile of this chemical and to confirm
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whether the mitigation measures being required are adequate or if additional measures are
warranted. These data will be required as a part of the data call-in that will accompany this RED.
Metam-Sodium Non-Cancer Occupational Risk Concerns - Short- and Intermediate-Term
Dermal Risks from Metam-Sodium Exposure
The Agency revised the non-cancer, short- and intermediate-term occupational handler
dermal exposure assessments based on the additional usage and occupational exposure
information provided by the metam-sodium sewer use registrants. The results of the revised non-
cancer, short-term occupational handler dermal exposure assessments for the sewer use of
metam-sodium indicate that the MOEs for the dermal risk to handlers with engineering controls
(e.g., closed mixing and loading systems) were above or just below the target MOE of 100, and
the MOEs for the dermal risk to handlers with full dermal PPE (i.e., chemical resistant gloves
and double layer clothing) were above 49, even at the highest daily rates of amount of product
handled. In the case of the intermediate-term exposures with full dermal PPE, MOEs were below
the target MOE of 100, even with engineering controls. Revised risk estimates are given in Table
13 below.
Table 13: Metam-Sodium Non-cancer Dermal Sewer Handler Risk Estimates
Application Rate
(Ibs ai/gal)
Amount Handled
Daily (gals)
Baseline
MOE
PPE-G1
MOE
PPE-
G\DL2
MOE
Eng Cont
MOE6
Short-term Margins of Exposure 3
0.111
0.127
500 5
11255
500 5
11255
0.73
0.33
0.64
0.29
93
41
81
36
130
56
110
49
250
110
220
96
Intermediate-term Margins of Exposure 4
0.111
0.127
500 5
11255
500 5
11255
0.017
0.0077
0.015
0.0068
2.2
0.97
1.9
0.85
3
1.3
2.6
1.2
5.9
2.6
5.1
2.3
1 G = gloves.
2 DL = double layer of clothing.
3 Short-term margins of exposure are calculated using a NOAEL of 4.22 mg/kg/day from a developmental rat
toxicity study. Short-term target MOE = 100.
4 Intermediate-term margins of exposure are calculated using a NOAEL of 0.1 mg/kg/day from a chronic dog
toxicity study. Intermediate-term target MOE = 100.
5 500 and 1125 gallons handled per day equals treating 4,000 and 9,000 linear sewer feet per day.
6 Engineering controls = mixing and loading activities, but not applications.
Although not all short- and intermediate-term dermal exposure MOEs reached the target
MOE of 100 with the required dermal protection and engineering controls, the occupational
handler dermal exposure assessments are considered to be very conservative. Coupled with the
Agency's dermal PPE requirements (i.e., chemical resistant gloves and double layer clothing)
and engineering control requirements (i.e., closed mixing and loading systems), the Agency
believes that it is being protective of possible metam-sodium short-term and intermediate-term
dermal risks. The occupational dermal risk assessments are based on data from the Pesticide
Handler Exposure Database (PHED). PHED was designed to be used only to assess nonvolatile
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pesticides. In the case of metam-sodium sewer use, PHED was used because there is no data
available to the Agency to assess exposure to metam-sodium itself. Since metam-sodium
degrades rather quickly to MITC, the dermal short- and intermediate-term sewer risk assessment
for metam generated by the Agency using data from PHED can be considered very conservative.
In addition, the mixer-loader open-pour exposure information from PHED used to estimate risk
for sewer use handlers of metam-sodium mixing, loading, and applying is not necessarily a good
representation of the actual sewer application activities. The PHED scenario assumes that the
handler is directly mixing and pouring the chemical into the application tank, while application
information provided by the registrants describes a lower-exposure practice in which the
applicator unrolls a hose into the manhole cover and then rolls the hose out of the manhole cover
as the chemical is being applied.
Another source of conservatism comes from the fact that both the short- and
intermediate-term dermal exposure assessments assume that workers are exposed throughout an
8-hour workday. However, the Agency believes that the amount of time workers are exposed to
metam-sodium each day is limited to the amount of time spent loading and applying metam-
sodium, which the Agency has estimated at 2 hours per day, based upon information submitted
by the registrant, Douglas Products and Packaging Company.
To address the short- and intermediate-term dermal risks from metam-sodium, consistent
with the mitigation required in the July 2008 metam-sodium/potassium RED, the Agency is
requiring that any person(s) engaged in any activities that are likely to involve direct contact with
metam-sodium (including, but not limited to, mixing, loading, and/or applying metam-sodium;
equipment calibration; cleaning and repair of application equipment; entering into treated areas;
sampling cleanup spills; and rinsate disposal) be required to wear double-layer clothing and
chemical-resistant gloves.
In addition to the worker PPE requirements, the Agency will also require closed
engineering systems for all mixing and loading of metam-sodium for sewer use. In addition, all
systems must be capable of removing the pesticide from the shipping container and transferring
it into mixing tanks and/or application equipment. At any disconnect point, the system must be
equipped with a dry disconnect or dry couple shut-off device that is warranted by the
manufacturer to minimize drippage. Finally, handlers will also be required to position a clean
water rinse hose to continually rinse off the application hose as it is extracted from the sewer
pipe. All of these mitigation measures are designed to further protect handlers from exposures.
These additional requirements are a result of information that the Agency received from Douglas
Products and Packaging Company during the post-RED comment period regarding typical usage
scenarios, which included such practices.
To better evaluate the dermal exposure to mixer/loader/applicators of metam sewer use
applications and to confirm whether the mitigation measures included in this RED are adequate
and/or determine whether additional mitigation measures are warranted, the Agency also will be
requiring the registrants to submit outdoor dermal exposure data (GLN 875.1100) and product
use information (875.1700) as a part of the data call-in that will accompany this RED.
Metam-Sodium Cancer Occupational Risk Concerns
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EPA revised its occupational handler dermal cancer assessment for handlers engaged in
sewer applications of metam-sodium to control roots in sewer systems based on the additional
usage and occupational exposure information provided by the metam-sodium sewer use
registrants during the post-RED comment period. The results of the revised cancer occupational
handler dermal exposure assessment for the sewer use of metam-sodium indicate that cancer
risks for workers in full dermal PPE requirements (i.e., chemical resistant gloves and double
layer clothing) and/or those using engineering control technologies (i.e., closed mixing and
loading systems) are below the target cancer risk level of between IxlO"4 to IxlO"6 for exposed
handlers. Revised risk estimates are given in Table 14 below.
Table 14: Metam-Sodium Cancer Sewer Risk Estimates
Application
Rate
(Ibs ai/gal)
0111
.111
Handled
Daily
(gals)
DUU
Hours
per Day
Exposed
z
Number
of Days
Treating
per
Year
160
220
160
220
Baseline
Cancer Risk
2.5E-04
1.8E-04
2.8E-04
2.1E-04
PPE-G1
Cancer Risk
2.0E-06
1.4E-06
2.3E-06
1.6E-06
PPE-G1 ,DL2
Cancer Risk
1.4E-06
1.1E-06
1.7E-06
1.2E-06
Eng Cont
Cancer Risk
7.3E-07
5.3E-07
8.4E-07
6.1E-07
1 G = gloves.
2 DL = double layer of clothing.
3 500 gallons handled per day equals treating 4,000 linear sewer feet per day.
Potential Impacts of Metam-Sodium on Nitrifying Bacteria at Downstream Water Treatment
Facilities
During the Phase 5 and post-RED comment periods, the Agency received comments
from various stakeholders, including Sewer Sciences Inc. and wastewater treatment plant
personnel, indicating that metam-sodium impacted downstream wastewater treatment plant
operations as a result of bacterial upset. Some wastewater treatment plant personnel provided
anecdotal information that the use of metam-sodium led to upsets in the microorganisms at their
facilities, but specific details regarding the circumstances that led to these upsets were not
provided. During this period, the Agency also received comments from Douglas Products and
Packaging and other wastewater treatment plant personnel, indicating that they have observed no
evidence that metam-sodium has led to impacts on downstream wastewater treatment plant
operations as a result of bacterial upset.
The Agency evaluated the available literature to determine whether there is the potential
concern for impacts to wastewater treatment plant microorganisms following application of
pesticide products containing metam-sodium. Based on this analysis, the Agency has determined
that "it appears as though there is a reasonable body of evidence to indicate that there may be
circumstances in which application of pesticide products containing metam-sodium to control
intrusion of roots into sewage collection pipes and storm drains could adversely affect activated
sludge microorganisms in wastewater treatment plants downstream of sites where such products
have been applied." For full details on the Agency's analysis, please see the 4-16-09
Antimicrobial Division memo, "Evaluation of Potential Impacts to Wastewater Treatment Plan
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Microorganisms Following Application of Pesticide Products Containing Metam Sodium
(sodium methyldithiocarbamate) as an Active Ingredient to Control Intrusions of Roots into
Sewage Collection Pipes and Storm Drains, located in the metam-sodium and metam-potassium
docket at EPA-HQ-OPP-2005-0125].
To mitigate the Agency's concern over potentially harmful effects of metam-sodium on
denitrifying bacteria and the associated disruption to downstream sewage treatment facilities, the
Agency is requiring applicators to notify downstream wastewater facilities prior to the start of
metam-sodium applications so that they may monitor the operations of the wastewater treatment
plant. The applicators are required to report how much product they are applying to the sewer
system to operators of downstream water treatment plants and to inform these operators that high
concentrations of these chemicals in wastewater may adversely affect the biological sewage
breakdown process in wastewater treatment plants.
Conclusion for Sewer Root Control Use
EPA has evaluated the need for control of invasive roots in sewer systems and the
available chemical, mechanical, and non-chemical alternatives to metam-sodium, concluding that
each type of control has a place in effective sewer maintenance (see Revised Alternatives
Assessment on Root Control Use ofMetam-Sodium in Sewer Lines (DP # 358321) and Response
to Public Comments Received dated May 8, 2009 which is available in the metam-sodium and
metam-potassium docket at EPA-HQ-OPP-2005-0125.
Based on the short- and intermediate-term dermal exposure risks to workers, coupled
with the worker risks associated with MITC inhalation exposures, the Agency is requiring that
any person(s) engaged in any activities that are likely to involve direct contact with metam-
sodium, including but not limited to mixing, loading, and/or applying metam-sodium; equipment
calibration; cleaning and repair of application equipment; entering into treated areas; sampling
cleanup of spills; and rinsate disposal, to wear double-layer clothing, chemical resistant gloves,
and a 90% protection factor respirator approved for MITC. To help mitigate these risks, the
Agency is also adding a requirement that closed engineering systems for all mixing and loading
activities be used.
To mitigate potentially harmful effects of metam-sodium on denitrifying bacteria and the
associated disruption to downstream sewage treatment facilities, the Agency is requiring
applicators to notify downstream waste water facilities prior to the start of metam-sodium
applications so that they may monitor the operations of the wastewater treatment plant.
Based on the revised occupational risk assessments, coupled with the conservative nature
of the short- and intermediate-term non-cancer data, the Agency finds that these measures will be
adequate to address the risks associated with the sewer use of metam-sodium.
c. Antimicrobial Uses
For details on the metam-sodium, metam-potassium, and MITC human health risk
assessments, please refer to the Human Health Risk Assessments and addenda for these
chemicals. The following documents are recent additions:
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• EPA-HQ-OPP-2005-0125-0267, Updated Label Language for the Antimicrobial Uses of
Methyl Isothiocyanate (MITC) (PC Code 068103) for the Reregi strati on Eligibility
Decision Document. May 13, 2008.
• EPA-HQ-OPP-2005-0125-0266, Risk Mitigation Measures, Voluntary Cancellations and
Updated Label Language for the Antimicrobial Uses of Metam Potassium (PC Code
039002) for the Reregi strati on Eligibility Decision Document. May 15, 2008.
• EPA-HQ-OPP-2005-0125-0265, Risk Mitigation Measures, Voluntary Cancellations and
Updated Label Language for the Antimicrobial Uses of Metam Sodium (PC Code
039003) for the Reregi strati on Eligibility Decision Document. May 15, 2008.
These documents are also available in the public docket EPA-HQ-OPP-2005-00125,
located on-line in the Federal Docket Management System (FDMS) at www.regulations.gov.
During the post-RED comment period, the Agency received a comment from Sewer
Sciences, Inc., which identified errors on pages 86 and 88 of the RED, wherein the Agency
inadvertently included a combined cancer risk value of metam sodium and metam potassium.
The risk information presented in the risk assessments for the antimicrobial uses of metam
sodium and metam potassium correctly state the cancer risk for antimicrobial uses of both metam
sodium and metam potassium. This error has been corrected below.
MITC
The results from the occupational and potential bystander assessment indicated that the
occupational and potential bystander risks to the remedial wood treatment uses of MITC (i.e.,
treatment of utility poles, pilings, bridge timbers, and laminated wood products located outdoors)
are expected to be negligible, based on the product formulation, product packaging, method of
application, and required use of PPE during the application activity.
Mitigation for Wood Pole/Piling Use:
The Agency is requiring the following label requirements, which are also contained in the
label table, in Section V.
1. "Plug the pre-drilled holes immediately after applications,"
2. "Do not treat structures/beams indoors," and
3. "Do not drill an application hole through seasoning checks to apply product. If the hole
intersects a check, plug the hole and drill another. If more than two treatment holes
intersect an internal void or rot pocket, redrill the holes farther up the pole into relatively
solid wood."
Metam-sodium
The results of the occupational assessment for most antimicrobial uses of metam-sodium
(i.e., treatment of poles and pilings, leather processing, and treatment of sewage sludge)
indicated that the non-cancer dermal and inhalation risks to handlers were not of concern (i.e., all
MOEs are greater than the target of 100). The cancer risks for the rest of the metam-sodium uses
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were in the range of 1. le-4 to 6.8e-6, where the target cancer risk level is between le-4 to le-6
for occupationally exposed workers.
Because of the short loading and/or application durations (i.e., minutes), handlers (i.e.,
mixers/loaders) are not expected to be exposed to the metam-sodium degradate, MITC.
Occupational post-application and potential bystander (i.e., residents) exposure to MITC after the
pole treatment is considered negligible. Any migration of MITC through the wooden cap into
the ambient air conditions is considered negligible. However, the Agency has concerns for
potential post-application inhalation exposures to MITC after metam-sodium applications in the
leather and/or sugar processing industries and also for workers in the vicinity of sewage sludge
treatments. However, no data are available to estimate the air concentrations at these types of
processing facilities.
The following uses have been voluntarily cancelled for metam-sodium: (1) the sugar
beet/sugar cane use and (2) all leather and hide processing uses. One registrant has voluntarily
cancelled the organic sludge fumigation use; however, this use is still being maintained by
another registrant. Therefore, the antimicrobial uses of metam-sodium that remain include: (1)
the remedial treatment of wooden poles and timbers and (2) treatment of sewage sludge and
animal waste.
Mitigation for Wood Pole/Piling Use:
The Agency is requiring the following label requirements, which are included in the label
table, in Section V.
1. "Plug the pre-drilled holes immediately after applications,"
2. "Do not treat structures/beams indoors," and
3. "Do not drill an application hole through seasoning checks to apply product. If the hole
intersects a check, plug the hole and drill another. If more than two treatment holes
intersect an internal void or rot pocket, re-drill the holes farther up the pole into relatively
solid wood."
Mitigation for Use to Treat Sewage Sludge and Animal Waste:
The Agency is requiring the new label language be developed, which states that the
treated material is placed in a protected storage area for 21 days. The current label language
reads that the treated material needs to be paced in a protected storage area for 14-21 days or
until a phytotoxicity test is completed. This new label language is contained in the Label Table,
in Section V.
Metam-potassium
The results of the occupational assessment for most antimicrobial uses of metam-
potassium (i.e., pulp and paper, leather, sugars, and emulsions and cutting fluids) indicated that
the non-cancer dermal and inhalation risks to handlers were not of concern (i.e., all MOEs are
greater than the target of 100). However, the occupational assessment results of metam-
potassium used in water cooling systems exceeded the Agency's level of concern (i.e., MOEs
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were less than the target of 100) for dermal and inhalation exposures of handlers during open-
pouring activities. Similarly, the cancer risk for the handlers of liquid open-pour products in
water cooling facilities was also of concern, and is 2.9e-3. The cancer risks for the rest of the
metam-sodium and metam-potassium handlers were in the range of 1.1 e-4 to 1.6e-8, where the
target cancer risk level is between le-4 to le-6 for occupationally exposed workers.
Because of the short loading and/or application durations (i.e., minutes), handlers (i.e.,
mixers/loaders) are not expected to be exposed to the metam-potassium degradate, MITC.
However, the Agency has concerns for potential post-application inhalation exposures to MITC
for workers in the vicinity of metam-potassium applications in the leather, pulp/paper, and sugar
processing industries, as well as in coatings and metal working fluid manufacturing, oil-field
operations, cooling water towers, and industrial water purification facilities because MITC is a
highly volatile organic chemical (vapor pressure =150 mm Hg). Furthermore, since metam-
sodium and metam-potassium convert to MITC in aqueous media, the Agency also has concerns
for the potential MITC inhalation exposures for the machinist who works with metal-working
fluids that were preserved with metam-potassium.
While industrial workers are not expected to be exposed to MITC while mixing or
loading paint products containing metam-potassium, bystanders in the vicinity of freshly painted
areas and occupational/professional workers and residential (do-it-yourself) applicators could
have potential inhalation exposure to MITC. (It is assumed that all metam-potassium used in
paint products converts to MITC.) All of the professional painter MOEs for all time durations
exceeded the Agency's level of concern (target MOE of 10). At the maximum application rate,
the residential painter MOEs for the 8-hour and 28-day durations also exceed the Agency's level
of concern. Furthermore, at the maximum application rate, the post-application bystander MOE
for all durations also exceeds the Agency's level of concern.
The technical registrants have chosen to voluntarily cancel the following uses of metam-
potassium: (1) the sugar beet/sugar cane use; (2) all leather uses, with the exception of the
tanning drum leather applications; (3) all paint uses (inclusive of the preservation of protective
colloids and emulsion resins); (4) all water-based drilling, completion, and packer fluid uses; (5)
all petroleum secondary recovery operations uses; (6) all once-through cooling water
applications; and (7) all cutting fluids (metalworking fluids) uses. Those antimicrobial uses of
metam-potassium that remain include: (1) the tanning drum leather use, (2) pulp and paper, (3)
recirculating cooling water systems, and (4) industrial water purification systems.
Mitigation for Cooling Water Tower Use:
Both the dermal and inhalation risk and the cancer risk to occupational workers during
open-pour activities for the recirculating cooling water tower use are mitigated by requiring the
use of a metering pump system for the recirculating cooling tower use. Label requirements will
include the following, which is also contained in the label table, in Section V.
• "This antimicrobial product may only be used in recirculating cooling water facilities."
• "This antimicrobial product can only be applied to recirculating cooling water systems
via a metering pump system."
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• Update PPE to be inclusive of long sleeves, long pants, chemical resistant gloves, and
goggles or face shield.
2. Endocrine Disrupter Effects
EPA is required under the FFDCA, as amended by FQPA, to develop a screening
program to determine whether certain substances (including all pesticide active and other
ingredients) "may have an effect in humans that is similar to an effect produced by a naturally
occurring estrogen, or other such endocrine effects as the Administrator may designate. "
Following the recommendations of its Endocrine Disrupter Screening and Testing Advisory
Committee (EDSTAC), EPA determined that there were scientific bases for including, as part of
the program, androgen and thyroid hormone systems, in addition to the estrogen hormone
system. EPA also adopted EDSTAC's recommendation that the Program include evaluations of
potential effects in wildlife. When the appropriate screening and/or testing protocols being
considered under the Agency's Endocrine Disrupter Screening Program (EDSP) have been
developed and vetted, metam-sodium, metam-potassium, and MITC may be subjected to
additional screening and/or testing to better characterize effects related to endocrine disruption.
3. Endangered Species Considerations
The Agency has not conducted a risk assessment that supports a complete
endangered species determination. The ecological risk assessment planned during registration
review will allow the Agency to determine whether metam-sodium, metam-potassium and MITC
use has "no effect" or "may affect" federally listed threatened or endangered species (listed
species) or their designated critical habitats. When an assessment concludes that a pesticide's
use "may affect" a listed species or its designated critical habitat, the Agency will consult with
the U.S. Fish and Wildlife Service and/or National Marine Fisheries Services (the Services), as
appropriate.
D. Conclusion
The Agency has determined that products containing metam-sodium, metam-potassium
and MITC are eligible for reregi strati on provided the risk mitigation measures outlines above are
adopted and label amendments are made to reflect these measures. Where labeling revisions are
warranted, specific language is set forth in the label. Table in Section V of the document.
V. What Registrants Need to Do
EPA recognizes that the extent of the mitigation needed for metam-sodium and metam-
potassium and the other soil fumigants will require continued coordination among state
regulatory agencies, EPA, registrants, growers and other stakeholders to ensure that all
provisions of the RED are understood, that data are developed and evaluated expeditiously, and
that bystander and worker protection measures are implemented as soon as practicable.
When the soil fumigant REDs were issued in July, 2008, EPA specifically requested
comment on the mechanisms and timing of implementing the provisions of the REDs. After
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considering stakeholder comments largely focused on the challenges of implementing many new
measures simultaneously, EPA has developed the following schedule:
July 2008
October 2008
May 2009
Mid 2009
September 1, 2009
December, 2009
During 2009-10
September 1, 2010
2009-2012
2013-
and other fumigants
Labeling
Metam-sodium/potassium REDs issued.
Comment period closed.
EPA responds to comments, amends RED as appropriate.
EPA issues product and generic DCIs.
Registrants must submit revised labels to EPA, reflecting phase one of
the mitigation measures as outlined in Table 2: restricted use, GAPs, rate
reductions, limitations on use sites, new handler protection measures, tarp
cutting and removal restrictions, extended worker re-entry restrictions,
training information for workers, and relevant portions of the FMP
requirements.
EPA reviews/approves new labeling for 2010 use season.
EPA works with registrants, states and stakeholders to develop and begin
implementation of first responder and community outreach, applicator
training, and compliance assistance and assurance measures.
Registrants must submit revised labels to EPA reflecting all remaining
mitigation measures outlined in Table 2 including:
applicator training, restrictions on applications near sensitive sites, buffer
zones, buffer credits, buffer zone posting and buffer overlap prohibitions
and exceptions, and the full FMP requirements.
Registrants develop data per DCIs.
EPA begins Registration Review for metam-sodium and metam-potassium
Registrants must submit labeling reflecting phase one mitigation measures by September
1, 2009. All measures will need to be reflected on labels submitted to EPA by September 1,
2010. Because of the relatively large amounts of product shipped under a single label, e.g., 50
gallon drums and railroad tank cars, changes to fumigant labeling can be adopted relatively
quickly. Therefore, the Agency anticipates that labeling approved late in 2009 would begin to
appear on products used for the 2010 fumigation season.
The Agency has determined that, with the mitigation measures identified in this document,
some metam-sodium, metam-potassium, and MITC uses are eligible for reregistration; however,
additional data are required to confirm this decision. In the near future, the Agency intends to
issue data call-in (DCI) notices requiring product-specific data and generic (technical grade)
confirmatory data. Generally, registrants will have 90 days from receipt of a DCI to complete
and submit response forms or request time extension and/or waiver requests with a full written
justification.
A. Manufacturing Use Products
1. Additional Generic Data Requirements
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The generic data base supporting the reregi strati on of metam-sodium, metam-potassium,
and MITC has been reviewed, and data gaps exist. The data listed below are necessary to
confirm the reregi strati on eligibility decision documented in this RED and determine whether the
mitigation measures outlined in this RED are adequate or if additional measures are warranted.
The Agency is requiring the following toxicity studies.
OPPTS
Guideline
Number
870.6200
870.3550
870.3800
870.5550
870.4200
870.4200
Data Requirement
Neurotoxicity Screening Battery - Inhalation
Developmental Toxicity Screening Test -
Inhalation
Reproduction and Fertility Effects - Inhalation
Unscheduled DNA Synthesis in Mammalian
Cells in Culture
Chronic/Carcinogenicity Rats - Inhalation
Chronic/Carcinogenicity Mice - Inhalation
Study
type
TOX
TOX
TOX
TOX
TOX
TOX
870.6200 - Neurotoxicity Screening Battery
An acute neurotoxicity study in rat via the inhalation route with pathological evaluation
of the complete respiratory tract is being requested. The Agency is currently using single day,
acute exposures in its consideration of buffer zones following applications of metam-sodium and
metam-potassium. The toxicology data available to inform this decision are limited to an eye
irritation study in human subjects and an acute inhalation study. The purpose of the acute study
was to determine the LC50, not for use in hazard identification for human health risk assessment.
The Agency cannot evaluate the dose response relationship of irritation and systemic effects to
the nose and lungs using these studies. This information on the respiratory tract is critical for the
risk assessment as the relative sensitivity of eye irritation and more serious health outcomes is
unknown. The Agency is open to discussing MITC-specific changes to the standard
neurotoxicity screening battery to ensure that the appropriate target organs are evaluated and that
relevant dose-response data would be generated.
870.3550 - Developmental toxicity screening test - Inhalation
This inhalation developmental toxicity study in rat is being requested to further
characterize the toxicity profile of this compound via the inhalation route. MITC has been
shown to travel off fields to areas where the general public lives, works, and plays. As such, it is
appropriate to evaluate the effects of MITC on pregnant females and their fetuses.
870.3800 - Reproduction and Fertility Effects
Two generation reproduction study in rat via inhalation with pathological evaluation of
the complete respiratory tract in offspring is needed. This inhalation reproductive toxicity study
is being requested to further characterize the toxicity profile of this compound via the inhalation
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route. MITC has been shown to travel off fields to areas where the general public lives, works,
and plays. As such, it is appropriate to evaluate the effects of MITC on reproductive
performance and to pups directly exposed to MITC via the inhalation route. Note: the Agency
would be open to discussing with the registrant the potential for performing the new enhanced
one-generation reproductive study instead of the standard two-generation study.
870.5550 - Unscheduled DNA Synthesis in Mammalian Cells in Culture
This study is required to complete the genetic toxicity testing battery.
870.4200 - Chronic/Carcinogenicity Rats and Mice
Carcinogenicity studies for MYTCper se are insufficient to characterize cancer risk;
therefore, the carcinogenic potential of MITC cannot be determined at this time. Although there
are not expected to be exposures of six months or longer in duration in a given year, since the
same fields are often treated every year, there is potential for exposure to occur annually for
many years. Moreover, metaplasia of the respiratory epithelium, a lesion often associated
cancer, was observed after only 28 days of exposure in the subchronic inhalation study in rats
with MITC. As such EPA is requiring inhalation carcinogenicity studies with MITC in rats and
mice.
Additional data requirements for metam-sodium and metam-potassium soil uses
OPPTS
Guideline
Number
835.8100
875.1100
875.1300
Special
850.1075
850.1025
850.1035
850.4225
850.4250
850.4400
850.3020
Special
Special
Special
Special
Data Requirement
Field Volatility from soil
Dermal exposure - outdoor
Inhalation exposure - outdoor
Avian acute inhalation, MITC
Acute Marine/Estuarine Fish, MITC
Acute Marine/Estuarine Mollusk, MITC
Acute Marine/Estuarine Shrimp, MITC
Seedling Emergence - Tier II, MITC.
Vegetative Vigor - Tier II, MITC
Aquatic Plant Growth - Tier II, MITC (3
remaining species)
Honeybee Acute Contact
Community Outreach and Education Program
Training for Applicators Supervising
Fumigations
Training Materials for Handlers
Buffer Zone Posting Signs
Study
type
ORE
ORE
ORE
ECO
ECO
ECO
ECO
ECO
ECO
ECO
ECO
Special
Special
Special
Special
Data Requirements:
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The Agency is requiring the following volatility and human exposure studies which will
be used to confirm if bystander and worker risks are below the Agency's level of concern. They
will also be used to determine if additional mitigation measures are warranted:
• GLN 835.8100 - Field volatility from soil (center pivot, spray blade, and rotary tiller)
• GLN 875.1100 - Dermal exposure - outdoor
• GLN875.1300 - Inhalation exposure - outdoor
835.8100 - Field volatility from soil
Volatility studies are required for metam-sodium and metam-potassium soil uses to
determine flux for modeling purposes of the breakdown products of metam-sodium and metam-
potassium, including formaldehyde. Center pivot, spray blade, and rotary tiller application
methods should be included.
For center pivot applications the Agency is requiring field volatility studies for all
application methods including high release, medium release and low release application
methods. In addition, the field volatility study for low release applications should evaluate the
cumulative flux from 2 adjacent applications that are occurring at the same time.
875.1100 - Dermal exposure - outdoor and 875.1300 - Inhalation exposure - outdoor
These studies will be used to confirm if bystander and worker risks are below the
Agency's level of concern. They will also be used to determine if additional mitigation measures
are warranted.
Special - Avian acute inhalation, MITC
The current estimate of avian risk is based largely on the mammal assessment. This
study will enable an inhalation risk assessment specific to birds. This is critical, since avian
exposure to MITC is expected to be largely via inhalation.
850.1075 - Acute Marine/Estuarine Fish. MITC
The aquatic risk assessment of metam-sodium and metam-potassium use is based on
exposure to MITC. Given the use patterns evaluated, marine/estuarine species could also be
exposed. This study will enable a risk assessment for marine/estuarine species exposure.
850.1025 - Acute Marine/Estuarine Mollusk. MITC
The aquatic risk assessment of metam-sodium and metam-potassium use is based on
exposure to MITC. Given the use patterns evaluated, marine/estuarine species could also be
exposed. This study will enable a risk assessment for marine/estuarine species exposure. It will
also improve certainty with the endangered species risk assessment, as this test species may be
more representative of endangered freshwater mussels than the freshwater Daphnia.
850.1035 - Acute Marine/Estuarine Shrimp. MITC
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The aquatic risk assessment of metam-sodium and metam-potassium use is based on
exposure to MITC. Given the use patterns evaluated, marine/estuarine species could also be
exposed. This study will enable a risk assessment for marine/estuarine species exposure.
850.4225 - Seedling Emergence - Tier IL MITC
Metam-sodium and metam-potassium are used in part due to the phytotoxicity of MITC
at the application site. This study will enable the assessment of risk to non-target terrestrial
plants off site.
850.4250 - Vegetative Vigor - Tier IL MITC
Metam-sodium and metam-potassium are used in part due to the phytotoxicity of MITC
at the application site. This study will enable the assessment of risk to non-target terrestrial
plants off site.
850.4400 - Aquatic Plant Growth - Tier IL MITC
Only one of four tests currently available (on duckweed) is considered to be acceptable
(Core) (MRID #45919422). The submission of data for remaining test species under this
guideline will reduce uncertainty and improve the assessment of risk to aquatic plants. For
example, the blue-green alga and green alga studies are 72-hour OECD studies that are only
accepted as Tier I screening studies.
850.3020 - Honeybee acute contact MITC
Although there is honeybee data for metam-sodium and metam-potassium indicating that
it is relatively non-toxic to honey bees, there is a concern that MITC could be more toxic to bees.
Therefore, honeybee acute contact data is required for MITC.
Special Study - Community Outreach and Education Program
The Agency is requiring registrants to develop and implement community outreach and
education programs, including programs for first responders, to address these needs. Community
outreach and education programs must include the following elements, at minimum: (1) what
soil fumigants are and how they work, (2) what buffer zones are, (3) early signs and symptoms
of exposure, (4) appropriate steps to take to mitigate exposures, (5) what to do in case of an
emergency, and (6) how to report an incident. EPA expects registrants' proposals for the first
responder programs described in Section IV will also be designed to integrate with existing local
first-response and emergency preparedness networks.
Special Study - Training for Applicators Supervising Fumigations
EPA has determined that training, developed and implemented by registrants to foster
product stewardship, will help reduce potential risks associated with failure to adequately
manage the complexities of fumigation, and failure to comply with fumigant product labeling.
Additionally, EPA believes that providing safety information to other fumigant handlers will
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help them understand and adhere to practices that will help handlers protect themselves from
risks of exposure.
Registrants are required to develop and implement training programs for applicators in
charge of soil fumigations on the proper use of and GAPs for soil fumigants. EPA is requiring
registrants to submit proposals for these programs. The training programs must address, at
minimum, the following elements: how to correctly apply the fumigant; how to protect handlers
and bystanders; how to determine buffer zone distances; how to develop a FMP and complete the
post fumigation application summary; how to determine when weather and other site-specific
factors are not favorable for fumigant application; how to comply with required GAPs and
document compliance in the FMP. The training program must be made available to applicators
at least annually. The registrant shall provide documentation, such as a card or certificate, to
each applicator that successfully completes the training. This documentation shall include the
applicator's name, address, license number, and the date of completion.
The registrant must be able to provide to federal, state, or local enforcement personnel,
upon request, the names, addresses, and certified applicator license numbers of persons who
successfully completed the training program, as well as the date of completion. Applicators
supervising fumigations must have successfully completed the program within the preceding 12
months and must document when and where the training program was completed in the FMP.
The registrants will be required to (1) develop a database to track which certified applicators
have successfully completed the training and (2) make this database available to state and/or
federal enforcement entities upon request. In addition, the applicator must provide to federal,
state, or local enforcement personnel, upon request, documentation that verifies completion of
the appropriate training program(s).
Training programs must also include information on how to develop and implement
emergency response plans to ensure that applicators are prepared in the event that a problem
develops during or shortly after the fumigant application. EPA is also requiring registrants to
incorporate a mechanism for evaluating the effectiveness of their training programs at conveying
the required information to participants and for determining whether participants have
successfully completed the training program.
Special Study - Training Materials for Handlers
EPA has determined that registrants must prepare and disseminate training information
and materials for other fumigant handlers, i.e., those working under the supervision of the
certified applicator in charge of fumigations. The training materials must address, at minimum,
the following elements: (1) what fumigants are and how they work, (2) safe application and
handling of soil fumigants, (3) air monitoring and respiratory protection requirements for
handlers, (4) early signs and symptoms of exposure, (5) appropriate steps to take to mitigate
exposures, (6) what to do in case of an emergency, and (7) how to report incidents. Registrants
must provide this training information through channels open to the public (e.g., via a website).
Pesticide labels will require that applicators supervising fumigations provide this training
information to handlers under their supervision before they perform any fumigant handling task,
or they must ensure that handlers have been provided the required information within the
preceding 36 months. The label will also require that the training information be provided in a
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manner that the handler can understand. Applicators supervising fumigations must ensure the
FMP includes how and when the required training information was provided to the handlers
under their supervision.
Special Study - Buffer Zone Posting Signs
EPA has determined that registrants must prepare and disseminate generic buffer zone
posting signs which meet the following criteria: (1) signs must remain legible during the entire
posting period (2) signs must meet the general standards outlined in the WPS for text size and
legibility (see 40 CFR §170.120). The requirements for the contents of the sign are as follows
The treated area sign (currently required for
fumigants) must state the following:
~ Skull and crossbones symbol
- "DANGER/PELIGRO,"
~ "Area under fumigation, DO NOT
ENTER/NO ENTRE,"
~ "Dazomet fumigant in USE,"
~ the date and time of fumigation,
~ the date and time entry prohibition is
lifted
- Name of this product, and
~ name, address, and telephone number of the
certified applicator in charge of the fumigation.
The buffer zone sign must include the
following:
— Do not walk sign
-- "DO NOT ENTER/NO ENTRE,"
~ "Dazomet OR [Name of product] Fumigant
BUFFER ZONE,"
~ contact information for the certified
applicator in charge of the fumigation
Registrants must capture all of the information above, excluding the contact information
for the certified applicator in charge of fumigating. However, registrants must provide
appropriate space on the sign, and the sign must be made of material appropriate for applicators
to write in this information on the buffer zone posting signs. Registrants must provide buffer
zone posting signs at the point of sale for applicators to use. EPA is requiring registrants to
submit proposals that must address their strategy for development and dissemination of the
buffer zone posting signs.
Additional data requirements for metam-sodium sewer uses
Because chemical-specific exposure data were not available to assess the sewer use of
metam-sodium, surrogate data for mixers and loaders from the Pesticide Handlers Exposure
Database (PHED) were used in the risk assessment. To better evaluate exposure and characterize
risk and to confirm that the mitigation measures included in this RED are adequate and/or
determine whether additional measures are warranted, the following data will be required for
metam-sodium:
• GLN 875.1100- Dermal exposure - outdoor
• GLN 875.1700- Product use information
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Because metam-sodium degrades into MITC, the Agency also needs MITC monitoring
data in the breathing zone of the mixer/loader/applicator. The following data will be
required for MITC:
• GLN 875.1300 - Inhalation exposure - outdoor
Given the specialized nature of these sewer-use studies, the Agency would like to discuss
the study design with the registrants before the studies are begun.
Additional data requirements for metam-sodium and metam-potassium antimicrobial uses
Because chemical-specific exposure data were not available to assess the antimicrobial
uses of metam-potassium, surrogate data from both the Pesticide Handlers Exposure Database
and the Chemical Manufacturers Association (CMA) were used to generate screening-level risk
assessments. Therefore, the following data are needed to confirm the mitigation measures
included in this RED are adequate, or if additional measures are warranted.
• GLN 875.1200 - Dermal exposure - indoor
• GLN 875.1400 - Inhalation exposure - indoor
• GLN 875.1600 - Applicator exposure monitoring data reporting
• GLN 875.1700 - Product use information
Because metam-sodium degrades into MITC, the Agency needs MITC air concentration
monitoring data for all enclosed facilities that utilize metam-sodium. For metam-sodium this
only includes sewage sludge and animal waste treatment facilities as the leather use and sugar
cane and beet uses are being voluntarily cancelled. The guideline numbers are as follows:
• GLN 875.2500 - Inhalation exposure study
• GLN 875.2700 - Product use information
• GLN 875.2800 - Description of human activity
• GLN 875.2900 - Post-application data reporting and calculations
Residue data are needed to support the metam-potassium antimicrobial use in pulp and
paper manufacturing. The purpose of this confirmatory study is to demonstrate that the paper
manufacturing processes remove any residual metam-potassium and MITC.
• GLN 860.1520
Because metam-potassium degrades into MITC, the Agency needs MITC air
concentration monitoring data for all enclosed facilities that utilize metam-potassium. For
metam-potassium this includes pulp and paper facilities, recirculating cooling water facilities,
leather processing facilities, and industrial water purification facilities. The guideline numbers
are as follows:
• GLN 875.2500 - Inhalation exposure study
• GLN 875.2700 - Product use information
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• GLN 875.2800 - Description of human activity
• GLN 875.2900 - Post-application data reporting and calculations.
2. Labeling for Manufacturing-Use Products
In order to be eligible for reregi strati on, amend all product labels to incorporate the risk
mitigation measures outlined in Section IV.
B. End-Use Products
1. Additional Product-Specific Data Requirements
Section 4(g)(2)(B) of FIFRA calls for the Agency to obtain any needed product-specific
data regarding the pesticide after a determination of eligibility has been made. The registrant
must review previous data submissions to ensure that they meet current EPA acceptance criteria
and, if not, commit to conduct new studies. If a registrant believes that previously submitted
data meet current testing standards, then the study master record identification numbers (MRIDs)
must be cited according to the instructions in the Requirement Status and Registrants Response
Form provided for each product. The Agency intends to issue a separate product-specific data
call-in (PDCI), outlining specific data requirements. For questions regarding the PDCI, contact
Karen Jones from OPP/SRRD's Product Reregi strati on Branch at (703) 308-8047 or by e-mail at
Jones.Karen@epa.gov.
2. Labeling for End-Use Products
In order to be eligible for reregi strati on, amend all product labels to incorporate the risk
mitigation measures outlined in Section IV.
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Appendix A: Uses Eligible for Reregistration
Metam Sodium (PC Code 039003) and Metam Potassium (PC Code 039002) Soil Fumigant Uses Eligible For Reregistration
Annual Use
Use Site
Soil Pre-Plant
Alfalfa,
Asparagus (nursery production only),
Artichokes,
Barley,
Basil,
Beet,
Berries, [includes all EPA Crop Group 13, Berries Group, i.e., blackberry (Rubus
eubatus); bingleberry; black satin berry; boysenberry; Cherokee blackberry;
chesterberry; Cheyenne blackberry; coryberry; darrowberry; dewberry; Dirksen
thornless berry; Himalayaberry; hullberry; lavacaberry; lowberry; lucretiaberry;
mammoth blackberry; marionberry; nectarberry; olallieberry; Oregon evergreen
berry; phenomenalberry; rangeberry; ravenberry; rossberry; Shawnee blackberry;
youngberry, and varieties and/or hybrids of these; blueberry (Vaccinium spp.);
currant (Ribes spp.); elderberry (Sambucus spp.); gooseberry (Ribes spp.);
huckleberry (Gaylussacia spp.); loganberry (Rubus loganobaccus); raspberry-black
and red (Rubus occidentalis, Rubus strigosus, Rubus idaeus)],
Broccoli,
Brussels sprouts,
Cabbage,
Carrot,
Cauliflower,
Celeriac,
Chineese greens or bok choy,
Cilantro,
Citrus (orchard replant only), [includes all of EPA Crop Group 10, Citrus Fruits, i.e.,
Formulation
Liquid,
Soluble
Concentrate
Application
Rate
320 Ibs.
a.i./Acre
Limitations
See
The
Label
Table
For
Specific
Use
Limitations.
159
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Annual Use
Use Site Formulation Application Limitations
Rate
calamondin (Citrus mitis X Citrofortunella mitis); citrus citron (Citrus medica);
citrus hybrids (Citrus spp.) (includes: chironja, tangelo, tangor); grapefruit (Citrus
paradisi); kumquat (Fortunella spp.); lemon (Citrus jambhiri, Citrus limon); lime
(Citrus aurantiifolia); mandarin (tangerine) (Citrus reticulata); orange, sour (Citrus
aurantium); orange, sweet (Citrus sinensis); pummelo (Citrus grandis, Citrus
maxima); satsuma mandarin (Citrus unshiu)],
Collard,
Corn,
Cover crops (i.e., crops planted between periods of regular crop production to
prevent soil erosion, control weeds, and improve soil quality that are incorporated
into the soil before the next crop is planted and may not be harvested for food or
feed),
Crops grown solely for seed,
Cucurbits [includes all of EPA Crop Group 9, Cucurbit Vegetables Group, i.e.,
chayote (fruit) (Sechium edule); Chinese waxgourd (Chinese preserving melon)
(Benincasa hispida); citron melon (Citrullus lanatus var. citroides); cucumber
(Cucumis sativus); gherkin (Cucumis anguria); gourd, edible (Lagenaria spp.)
[includes: hyotan, cucuzza (Luffa acutangula, L. cylindrical; includes hechima,
Chinese okra)]; Momordica spp. (includes balsam apple, balsam pear, bitter melon,
Chinese cucumber); muskmelon [hybrids and/or cultivars of Cucumis melo
(includes true cantaloupe, cantaloupe, casaba, crenshaw melon, golden pershaw
melon, honeydew melon, honey balls, mango melon, Persian melon, pineapple
melon, Santa Claus melon, and snake melon)]; pumpkin (Cucurbita spp.); squash,
summer (Cucurbita pepo var. melopepo) (includes: crookneck squash, scallop
squash, straightneck squash, vegetable marrow, and zucchini);
squash, winter (Cucurbita maxima; C. moschata) (includes: butternut squash,
calabaza, hubbard squash) and (C. mixta; C. pepo) (includes acorn squash, spaghetti
squash); and watermelon (includes hybrids and/or varieties of Citrullus lanatus)],
Dill,
Eggplant,
Forest seedlings,
160
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Annual Use
Use Site Formulation Application Limitations
Rate
Ginger,
Grape (vineyard replant only),
Kale,
Kohlrabi,
Leafy greens [includes all of EPA Crop Group 4, Leafy Vegetables (Except Brassica
Vegetables), i.e., amaranth (leafy amaranth, Chinese spinach, tampala) (Amaranthus
spp.); arugula (roquette) (Eruca sativa); cardoon (Cynara cardunculus); celery
(Apium graveolens var. dulce); celery, Chinese (Apium graveolens var. secalinum);
celtuce (Lactuca sativa var. angustana); chervil (Anthriscus cerefolium);
chrysanthemum, edible-leaved (Chrysanthemum coronarium var. coronarium);
chrysanthemum; garland (Chrysanthemum coronarium var. spatiosum); corn salad
(Valerianella locusta); cress, garden (Lepidium sativum); cress, upland (yellow
rocket, winter cress) (Barbarea vulgaris); dandelion (Taraxacum officinale); dock
(sorrel) (Rumex spp.); endive (escarole) (Cichorium endivia); fennel, Florence
(fmochio) (Foeniculum vulgare Azoricum Group); lettuce, head and leaf (Lactuca
sativa); orach (Atriplex hortensis); parsley (Petroselinum crispum); purslane, garden
(Portulaca oleracea); purslane, winter (Montia perfoliata); radicchio (red chicory)
(Cichorium intybus); rhubarb (Rheum rhabarbarum); spinach (Spinacia oleracea);
spinach, New Zealand (Tetragonia tetragonioides, T. expansa); spinach, vine
(Malabar spinach, Indian spinach) (Basella alba); and swiss chard (Beta vulgaris var.
cicla)],
Leek,
Mint,
Mustard,
Nursery stock (fruit seedlings and rose bushes only),
Onion,
Ornamentals (floriculture only),
Pome fruit (orchard replant only), [includes all of EPA Crop Group 11, Pome Fruits
Group —Commodities, i.e., apple (Malus domestica); crabapple (Malus spp.);
loquat (Eriobotrya japonica); mayhaw (Crataegus aestivalis, C. opaca, and C.
rufula); pear (Pyrus communis); pear, oriental (Pyrus pyrifolia); and quince
161
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Annual Use
Use Site Formulation Application Limitations
Rate
(Cydonia oblonga)],
Peanut,
Pepper,
Potato,
Radish,
Rye,
Sugar beet,
Soybean,
Stone fruit (orchard replant only), [includes all of EPA Crop Group 12, Stone Fruits
Group—Commodities, i.e., apricot (Prunus armeniaca); cherry, sweet (Prunus
avium); cherry, tart (Prunus cerasus); nectarine (Prunus persica); peach (Prunus
persica); plum (Prunus domestica, Prunus spp.); plum, Chickasaw (Prunus
angustifolia); plum, Damson (Prunus domestica spp. insititia); plum, Japanese
(Prunus salicina); plumcot (Prunus. armeniaca X P. domestica); prune (fresh)
(Prunus domestica, Prunus spp.)],
Strawberries,
Sugar beet,
Sweet potato,
Swiss Chard,
Tobacco,
Tomatoes,
Tree nuts (orchard replant only), [includes all of EPA Crop Group 14, Tree Nuts
Group (i.e., almond (Prunus dulcis); beech nut (Fagus spp.); Brazil nut (Bertholletia
excelsa); butternut (Juglans cinerea); cashew (Anacardium occidentale); chestnut
(Castanea spp.); chinquapin (Castanea pumila); filbert (hazelnut) (Corylus spp.);
hickory nut (Carya spp.); macadamia nut (bush nut) (Macadamia spp.); pecan (Carya
illinoensis); and walnut, black and English (Persian) (Juglans spp.) as well as
pistachio],
Turnip,
Turf (including golf courses), and
Wheat
162
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Metam Sodium (PC Code 039003) Uses Eligible For Reregistration
Use Site
Formulatio
Sewer Use
Root Control in Sewer
Lines
liquid,
soluble
concentrate
(SC),
ready-to-use
(RTU)
Agricultural Premises & Equipment
Method of
Application
Foam
application
equipment
Application Rate/ No. of
applications
For sewers and drains, the
maximum application rate
is0.2121bsai/gallonof
solution.
Sewage Sludge & Animal
Waste Treatment
Wood Preservatives
Sewage
Sludge &
Animal
Waste
Treatment
Sewage Sludge
& Animal
Waste
Treatment
Sewage Sludge & Animal
Waste Treatment
Use Limitations
Do not discharge effluent containing this
product to sewer systems without previously
notifying the local sewage treatment plant
authority. For guidance, contact your State
Water Board or Regional Office of the EPA.
Sewage Sludge & Animal Waste Treatment
163
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Timbers and Wood
Poles/Pilings
Ready to
Use Liquid
Fumigant is
poured into
holes that have
been drilled into
section of poles
where decay is
detected
Wood Poles: Drill holes at
a 45 degree angle to a
length of approximately 2
!/2 times the radius of the
wood. The first hole
should be at the groundline
and succeeding holes
approximately 6-8 inches
higher and 90 degrees
rotated from the next lower
hole. The amount of
fumigant to be used per
pole is based on the pole
circumference at the
groundline.
Plug holes with treated
wood plugs.
None Listed
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Metam Potassium (PC Code 039002) Uses Eligible For Reregistration
Use Site
Formulation
Industrial Processes and Water Systems
Recirculating Cooling Ready to Use
Tower Water
Method of
Application
Chemical
metering
pumps
Application Rate/ No. of
applications
Initial Slug: 5.1 to 10.2
fluids ounces of product
per 1000 gallons of water.
Subsequent Dose: 1.7 to
10.2 fluid ounces per 1000
gallons of water every 1 to
5 days or as needed; or
Initial Dose: 6.9 to 13.9 fl.
Oz. of product per 1000
gallons of system water
(56-115 ppm).
Subsequent Dosage: 2.3 to
9.8 fl. Oz per 1000 gallons
of water (20-115 ppm); or
Initial Dose: 1.5 to 3.0 fl.
Oz. of product per 1000
gallons of system water
(15-30 ppm).
Subsequent Dosage: 0.5 to
3.0 fl. Oz per 1000 gallons
of water (5-30 ppm); or
Initial Dose: 3.3 to 6.6 fl.
Oz. of product per 1000
gallons of system water
Use Limitations
165
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Use Site Formulation Method of Application Rate/ No. of Use Limitations
Application applications
(30-60 ppm).
Subsequent Dosage: 1.1 to
6.6 fl. Oz per 1000 gallons
of water (10-60 ppm).
166
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Use Site
Industrial Water
Purification systems
(including reverse osmosis
systems, filters, clarifiers
and ion exchange
equipment)
Formulation
Ready to Use
Method of
Application
Chemical
metering
pumps
Application Rate/ No. of
applications
24.5 to 49.0 fl.Oz per 1000
gallons of water (200-400
ppm) for 4 to 6 hours.
Online Maintenance
treatment: 4.9 to 9.8 fl. Oz.
of product per 1000 gallons
of water (40 to 80 ppm) for
6-12 hours, once a week
or as needed; or
5.0 to 10.0 fl.Oz per 1000
gallons of water (50-100
ppm) for 4 to 8 hours.
Online Maintenance
treatment: 1.0 to 2.0 fl. Oz.
of product per 1000 gallons
of water (10 to 20 ppm) for
6-12 hours, once a week
or as needed.
Use Limitations
Not intended for use in potable water.
167
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Use Site
Pulp & Paper Mills
Formulation
Ready to Use
Method of
Application
Chemical
metering
pumps
Materials Preservatives
Paper making
(preservation)
Tanning Drum Leather
Ready to Use Chemical
metering
pumps
Ready to Use Open pour
Application Rate/ No. of
applications
0.25 to lib.of product per None Listed
short ton; or
0.8-5.0 Ibs of product per
ton for six hours; or
0.2 to 0.4 Ib of product per
ton.
75 to 400 ppm depending None Listed
onPH level.
To preserve tannery glue None Listed
solutions, add to glue at
rates of 100-250 ppm,
based on the total weight of
the glue solution
Use Limitations
168
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Use Site
Wood preservatives
Remedial Treatment:
Utility poles, piling,
bridge timbers, and
laminated wood products
(located outdoors).
MITC (068103) Uses Eligible For Reregistration
Reg. no./ Method of Application Rate/ No. of
Formulation Application applications
Ready to Use
Manually
insert tube into
pre-drilled hole
Dosage Rate: 1 tube (30
grams) per drill hole;
Pole Circumference in
inches/No, of Tubes
Installed :
Use Limitations
Do not contaminate water, food or feed by
storage or disposal.
Do not use, pour, spill or store near an open
flame.
35" or less - 3 holes
beginning at ground line
spaced 120 degrees apart
and 6"to 8" higher than the
previous hole.
36" to 49" - 4 holes
beginning at the ground
line spaced 90 degrees
apart and 6" to 8" higher
than the previous hole.
50" to 59"- 5 holes
beginning at the ground
line spaced 70 degrees
apart and 6"to 8" higher
than the previous pole.
60" to 70" - 6 holes
beginning at ground line
spaced 60 degrees apart
and 4" to 6" higher than
169
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Use Site Reg. no./ Method of Application Rate/ No. of Use Limitations
Formulation Application applications
the previous hole.
70" to 80"- 7 holes. The
first 2 at ground line 160
degrees apart and the
remaining 5 spaced 60
degrees apart and 4" to 6"
higher than the previous
hole.
80" to 90"- 8 holes. The
first 2 at ground line 180
degrees apart and the
remaining 6 spaced 50
degrees apart and 4" to 6"
higher than the previous
hole.
Over 90"- 9 holes. The
first 2 at ground line 180
degrees apart and the
remaining 7 spaced 45
degrees apart and 4" to 6"
higher than the previous
hole.
170
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Appendix B: Studies Used to Make the Reregistration Decision
This section not currently available.
171
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Appendix C: Technical Support Documents
Additional support of this RED is maintained in the OPP docket at: http://www.regulations.gov
at EPA-HQ-OPP-2005-0125. This docket may be accessed in the OPP docket room located at S-
4900, One Potomac Yard 2777 S. Crystal Drive, Arlington, VA. It is open Monday through
Friday, excluding federal holidays, from 8:30-4:00 pm. All documents may be view in the OPP
docket room or downloaded or viewed via the internet.
Health Effects Support Documents
• "Metam Sodium: Third Revision of the HED Human Health Risk Assessment;" May
2009; Charles Smith; Health Effects Division, U.S. EPA.
• Methyl Bromide, 1,3-Dichloropropene, Chloropicrin, Dazomet, Metam
Sodium/Potassium, MITC: Health Effects Division (HED) Component of Agency
Response To Comments On 2008 Reregi strati on Eligibility Documents (Date May 14,
2009).
• "Methyl Bromide, 1,3-Dichloropropene, Chloropicrin, Dazomet, Metam
Sodium/Potassium, MITC; PC Codes 053201, 029001, 081501, 035602, 039003,
039002, 068103; Health Effects Division (HED) Component of Agency Response To
Comments On 2008 Reregi strati on Eligibility Documents;" May 2009; Charles Smith
and Jeff Dawson; Health Effects Division; U.S. EPA.
• EPA-HQ-OPP-2007-03 50-0172, MOA Mode of Action, Eye Irritation, and the Intra-
Species Factor: Comparison of Chloropicrin and MITC. June 25, 2008. DP Barcode
293356.
• "Methyl Bromide (PC Code 053201), Chloropicrin (PC Code 081501), Dazomet (PC
Code 035602), Metam Sodium and Potassium (PC Codes 039003 & 039002), MITC (PC
Code 068103), Updated Health Effects Division Recommendations for Good Agricultural
Practices and Associated Buffer Credits;" May 2009; Charles Smith and Jeff Dawson;
Health Effects Division; U.S. EPA.
• EPA-HQ-OPP-2007-0350-0173, Factors Which Impact Soil Fumigant Emissions -
Evaluation For Use In Soil Fumigant Buffer Zone Credit Factor Approach. June 9, 2008.
(DP Barcode 306857).
Biological and Economical Analysis Support Documents
• Evaluation of Potential Impacts to Wastewater Treatment Plant Microorganisms..."; PC
Code: 039003; DP Barcode: 364230; April 2009; Pat Jennings; Antimicrobials Division;
U.S. EPA.
• Response to comments on use site restrictions included in the Reregi strati on Eligibility
Decision (RED) for Metam-Sodium and Metam-Potassium (DP Barcode: 363544); May
2009; Nikhil Mallampalli, Chism, Becker; Biological and Economic Analysis Division;
U.S. EPA.
• Revised Alternatives Assessment on Root Control Use of Metam-Sodium in Sewer Lines
(DP # 358321) and Response to Public Comments Received (EPA Docket No. EPA-HQ-
OPP-2005-0125);" May 2009; Sunil Ratnayake and Tara Chandgoyal; Biological and
Economic Analysis Division; U.S. EPA.
• Identification of High-Use Fumigation Areas at State and County Levels (DP#364647);"
May 2009; Monisha Kaul and Jenna Carter; Biological and Economic Analysis Division;
U.S. EPA.
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Response to BEAD Related Public Comments Received on the Reregi strati on Eligibility
Decision for Chloropicrin, Dazomet, Metam Potassium, Metam Sodium, and Methyl
Bromide (DP# 363545) May 14, 2009.
Analysis of Soil Fumigant Risk Management Requirements using Geographic
Information Systems: Case Studies based on a Forest Seedling Nursery (DP#363546).
May 13, 2009.
Process for Defining High-Use Fumigation Areas at the State and County Levels
(DP#364647) May 14, 2009.
EPA-HQ-OPP-2007-0350-0168, Review of Stakeholder Submitted Impact Assessments
of Proposed Fumigant Buffers, Comments on Initial Buffer Zone Proposal, and Case
Studies of the Impact of a Flexible Buffer System for Managing By-Stander Risks of
Fumigants. June 25, 2008. DP Barcode 353940.
EPA-HQ-OPP-2007-0350-0169, Response to Phase 5 BEAD Related Public Comments
Received on the Reregi strati on of Chloropicrin, Dazomet, Metam Potassium, Metam
Sodium, and Methyl Bromide. June 25, 2008. DP Barcode 353940.
EPA-HQ-OPP-2007-03 50-0018, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam Sodium in Cucurbit Production.
EPA-HQ-OPP-2007-03 50-0019, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam Sodium in Eggplant Production.
EPA-HQ-OPP-2007-03 50-0020, Assessment of the Benefits Soil Fumigants (Methyl
Bromide, Chloropicrin, Metam-Sodium, Dazomet) Used by Forest Tree Seedling
Nurseries.
EPA-HQ-OPP-2007-03 50-0021, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin, Dazomet, and Metam Sodium for Use in Raspberry
Nurseries, Fruit and Nut Deciduous Tree Nurseries, and Rose Bush Nurseries in
California.
EPA-HQ-OPP-2007-03 50-0022, Assessment of the Benefits of Soil Fumigation with
Chloropicrin and Metam-sodium in Onion Production.
EPA-HQ-OPP-2007-0350-0023, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin, and Metam Sodium in Grape Production.
EPA-HQ-OPP-2007-03 50-0024, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin and Metam Sodium in Tree Nut Production.
EPA-HQ-OPP-2007-03 50-0025, Assessment of the Benefits of Soil Fumigation with
Chloropicrin and Metam Sodium in Pome Fruits Production.
EPA-HQ-OPP-2007-03 50-0026, Assessment of the Benefits of Soil Fumigation with
Methyl Bromide, Chloropicrin, and Metam Sodium in Stone Fruit Production.
EPA-HQ-OPP-2007-03 50-0027, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam Sodium in Bell Pepper Production.
EPA-HQ-OPP-2007-03 50-0028, Assessment of the Benefits of Soil Fumigation with
Metam Sodium in Potato Production.
EPA-HQ-OPP-2007-0350-0029, Assessment of Soil Fumigation with Chloropicrin,
Methyl Bromide and Metam-sodium in Strawberry Production.
EPA-HQ-OPP-2007-0350-0030, Assessment of the Benefits of Chloropicrin, Methyl
Bromide, Metam-sodium and Dazomet Use In Strawberry Nursery Runner Production.
EPA-HQ-OPP-2007-03 50-0031, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam-sodium on Sweet Potato Production.
EPA-HQ-OPP-2007-03 50-0032, Assessment of the Benefits of Soil Fumigation with
Chloropicrin in Tobacco Production.
EPA-HQ-OPP-2007-0350-0033, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, and Metam Sodium in Tomato Production.
173
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• EPA-HQ-OPP-2007-03 50-0034, Assessment of the Benefits of Soil Fumigation with
Metam-Sodium in Carrot Production.
• EPA-HQ-OPP-2007-03 50-003 5, Assessment of the Benefits of Soil Fumigation with
Metam Sodium in Peanut Production.
• EPA-HQ-OPP-2007-0350-0036, Assessment of the Benefits of Soil Fumigation with
Chloropicrin, Methyl Bromide, Metam Sodium and Dazomet in Ornamental Production.
• EPA-HQ-OPP-2007-0350-0037, BEAD'S Planned Impact Assessments on Agricultural
Sites with Significant Use of Soil Fumigants (Chloropicrin, Dazomet, Methyl Bromide,
Metam Potassium, and Metam Sodium.
Environmental Fate and Ecological Effects Support Documents
• EPA-HQ-OPP-2004-0159-0117 - Transmittal Memo for the Revised Environmental Fate
and Ecological Effects Risk Assessment for Metam Sodium and Metam Potassium.
• EPA-HQ-OPP-2004-0159-0118 Revised Environmental Fate and Ecological Effects Risk
Assessment for Metam Sodium and Metam Potassium.
Antimicrobial Assessment Support Documents
• EPA-HQ-OPP-2007-0350-1066, Phase 6 Response to Substantive Public Comments on
Antimicrobials Division's Occupational and Residential Assessments for the
Reregi strati on Eligibility Decision (RED) Documents for the following chemicals:
Methylisothiocyanate (MITC), Metam Sodium, Dazomet, and Chloropicrin.
Buffer Zone Credits Support Document
• Methyl Bromide (PC Code 053201), Chloropicrin (PC Code 081501), Dazomet (PC
Code 035602), Metam Sodium and Potassium (PC Codes 039003 &039002), MITC (PC
Code 068103), DP Barcode 362369, Updated Health Effects Division Recommendations
for Good Agricultural Practices and Associated Buffer Credits. May 14, 2009.
• EPA-HQ-OPP-2007-0350-1073, Factors Which Impact Soil Fumigant Emissions -
Evaluation for Use in Soil Fumigant Buffer Zone Credit Factor Approach. Dawson, J.
and Smith, C.; D306857; June 9, 2008.
• EPA-HQ-OPP-2007-0350-1078, Health Effects Division Recommendations for Fumigant
Data to Refine Exposure Assessments. DP Barcode 353724.
Risk Management Support Documents
• EPA-HQ-OPP-2007-0350-1077, SRRD's Response to Phase 5 Public Comments for the
Soil Fumigants. Rice, M. and McNally, R.; July 2008.
• EPA-HQ-OPP-2007-0350-0003, Risk Mitigation Options to Address Bystander and
Occupational Exposures from Soil Fumigant Applications.
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Appendix D: FMP Template-MeBr Example
Note: The Agency plans to work with the registrants and other stakeholders to develop a metam-sodium and metam-
potassium specific FMP that will serve as a template for growers and the States to use for the most common
application methods prior to the 2010 and 2011 growing season.
Certified Applicator Supervising the Fumigation
Name and phone number: License number
Employer name and address:
General Site Information
D Commercial applicator
D Private applicator
Date of completing registrant
training program:
Application block location, address, or global positioning system (GPS) coordinates:
Name, address, and phone number of owner/operator of application block:
General Application Information
Target application date/window: Brand name of fumigan
Tarps (check here if section is not applicable D )
Brand name : Lot # :
Name and phone number of contact person responsible for repairing tarps:
t: EPA Registration Number:
Thickness:
Schedule for checking tarps for damage, tears, and other problems:
Maximum time following notification of damage that the person(s) responsible
Minimum time following application that tarp will be repaired: Minin
Other factors used to determine when tarp repair will be conducted:
Name and phone number of contact person responsible for cutting Equipi
and/or removing tarps (if other than certified applicator):
Schedule and target dates for cutting tarps: Sched
Soil Conditions
Description of soil texture and moisture in application block: Descn
for tarp repair will respond:
lum size of damage that will be repaired:
"nent/methods used to cut tarps:
ale and target dates for removing tarps:
ption of method used to determine soil moisture level:
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Weather Conditions
Summary of the weather forecast for the day of the application and the 48-hour period following the fumigant application (may attach a copy
of printed forecast to FMP):
Buffer Zones
Application method:
D Bedded
D Broadcast
D Hot gas - outdoor
D Hot gas - greenhouse
D Hand held probes
Rate from
lookup table
on label (Ib
ai/A):
Block size
from lookup
table on label
(acres):
Credits applied:
D high barrier film
D organic content
D clay content
D other:
Total credits
Buffer zone
distance:
List and describe areas in the buffer zone that are not under the control of owner/operator of the application block:
Personal Protective Equipment for Handlers
Handler Task
Clothing
Respirator Type, Filter Cartridge
Type and Change-out Schedule
Eye
Protection
Gloves
Other
Emergency Response Plan
Description of evacuation routes:
Locations of telephones:
Contact information for first responders: Local/state/federal
contacts: Other contact information for emergencies:
Emergency procedures/responsibilities in case of an incident, equipment/tarp/seal failure, odor complaints or elevated air concentration levels
outside buffer zone suggesting potential problems, or other emergencies).
Posting Signs
Name and phone number of person that is doing posting:
Location of posting signs:
Procedures for posting and sign removal:
Site Specific Response and Management D Fumigation Site Monitoring or DResponse Information for Neighbors
If Response Information for Neighbors has been selected, completed the following:
If buffer zone is 25-100 ft: D Neighbors within 50 ft of buffer zone D No neighbors within 50 ft of buffer zone
If buffer zone is 100-200 ft: D Neighbors within 100 ft of buffer zone D No neighbors within 100 ft of buffer zone
If buffer zone is 200-300 ft: D Neighbors within 200 ft of buffer zone D No neighbors within 200 ft of buffer zone
If buffer zone is > 300 ft: D Neighbors within 300 ft of buffer zone D No neighbors within 300 ft of buffer zone
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If buffer zones overlap D Neighbors within 300 ft of buffer zone D No neighbors within 300 ft of buffer zone
List of residences and businesses informed (neighboring property owners):
Name, address, and phone number of person providing information:
Method used to provide information:
Notice to State Lead Tribal Agencies
If your state and/or tribal lead agency requires notice, list contacts that were notified:
Date notified:
Communication Between Applicator, Land Owner/Operator, and Other On-site Handlers
Plan for communicating to the land owner/operator and all on-site handlers (e.g., tarp cutters/removers, irrigators) requirements to comply
with label including location and start/stop times of buffer zones; timing of tarp cutting/removal, and PPE:
Names and phone numbers of persons contacted:
Date contacted:
Comments/notes:
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Site Map
Location of application block:
l__l Application block
I I Bus stop
I Inpatient clinic
IWBI Water body
I P I Prison
Map Legend
Buffer zone Property lines ~~ Roads
I DC I Daycare facility I I School
Well
Right-of-way Walkway, sidewalk, path
NAB|
Nearby application block
NH I . .
| lALF I
Nursing home I I Assisted living facility
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Handler Information
Handler Name, Address, and Phone
Number
Employer Name, Address, and Phone
Number
Tasks They are Trained and
Authorized to Perform
DateofPPE
Training
Date of
Medical
Qualification to
Wear a
Respirator
Date of Fit
Testing for
Respirator
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Air Monitoring Plan
For Buffer Zone Monitoring: (check here if section is not applicable D )
Name of handler
performing monitoring
activities
Handler address
Handler phone
number
Location of monitoring
Timing
For Handlers without Respiratory Protection: (check here if section is not applicable D )
If sensory irritation is experienced: D Intend to cease operations D Intend to continue operations with respiratory protection
If intend to continue operations with respiratory protection, complete section for Handlers with Respiratory Protection below.
If intend to cease operations - Name, address, and phone number of handler to perform monitoring
activities prior to operations resuming:
Monitoring equipment:
For Handlers with Respiratory Protection: (check here if section is not applicable D )
Representative Handler Tasks to be Monitored
Monitoring Equipment
Timing
Air Monitoring Plan for Methyl Bromide Formulation with < 20% Chloropicrin
For Buffer Zone Monitoring: (check here if section is not applicable D )
Name, address, and phone number of person(s) to perform sampling:
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Area or Structure to be Monitored Before Reentry is Permitted
Monitoring Equipment
Timing
For Handlers with Respiratory Protection:
Representative Handler Tasks to be Monitored
Monitoring Equipment
Timing
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Methyl Bromide FMP Check List
General Site Information
A map, aerial photo, or detailed sketch is attached to this FMP that shows each of the following with distances from the application site
labeled: field location, application block dimensions, buffer zones, property lines, roads, bus stops, water bodies, wells, rights-of-ways,
nearby application blocks, surrounding structures, and sites requiring V» and 1A mile buffer zones.
Supervision of Handlers
An on site certified applicator will directly supervise the handlers participating in the application starting when the fumigant is first
introduced into the soil and ending after the fumigant has stopped being delivered/dispensed to the soil and the soil is sealed.
After the application is complete, and before leaving the application block, the certified applicator has provided the owner/operator and
handlers with written information necessary to comply with the label and procedures outlined in the FMP.
Fumigant safe handling information has been provided to each handler involved in the application or confirm that each handler
participating in the application has received fumigant safe handling information in the past 12 months.
For all fumigation handling tasks, at least 2 WPS-trained handlers must be present.
Weather Conditions
Wind speed at the application site is a minimum of 2 mph at the start of the application or forecasted to reach at least 5 mph during the
application.
A shallow, compressed (low-level) temperature inversion is not forecast to persist for more than 18 consecutive hours during the 48-hour
period after the application.
An air-stagnation advisory is not in effect for the area where the application site is located.
If air temperatures have been above 100 degrees F in any of the 3 days prior to application, then soil temperature will be measured and
recorded in the post application summary report.
Soil Conditions
The soil has been properly prepared and the surface has been checked to ensure that it is free of clods that are golf ball size or larger.
The area to be fumigated has been tilled to a depth of 5 to 8 inches.
Field trash has been properly managed (e.g., residue from a previous crop has been worked into the soil to allow for decomposition prior
to fumigation, little or no crop residue is present on the soil surface, and crop residue that is present does not interfere with the soil seal).
The soil temperature at the depth of injection ^ 90 degrees F at the beginning of the application.
The soil moisture at 9 inches below the surface is sufficient (field capacity is 50 to 80 percent).
Trash pulled by the shanks to the ends of the field will be covered with tarp or soil before making the turn for the next pass.
Shank Applications (check here if section is not applicable D )
For tarped-broadcast and -bedded applications, injection points will be at least 8 inches from the nearest final soil/air interface.
For tarped-bedded applications, the injection depth will not be as deep as the lowest point of the tarp (i.e., the lowest point of the tuck).
For untarped-bedded applications, the injection points will be at least 12 inches from the nearest final soil/air interface.
For untarped-broadcast applications, the injection points will be at least 18 inches from the nearest final soil/air interface.
For broadcast untarped applications, a disc or similar equipment will be used to uniformly mix the soil to at least a depth of 3 to 4 inches
to eliminate the chisel or plow traces and will following elimination of the chisel trace, the soil surface will be compacted with a
cultipacker, ring roller, and roller in combination with tillage equipment.
For performed bed applications, the soil will be sealed by disruption of the chisel trace using press sealers, bed shapers, cultipackers, or
by re-shaping (e.g., relisting, lifting, replacing) the beds immediately following injection.
For beds formed at the time of application, the soil will be sealed by disrupting the chisel trace using press sealers, or bed shapers.
For shanked bedded and broadcast applications, tarps will be installed immediately after fumigant is injected into the soil.
Applicators have been trained and instructed not to apply or allow fumigant to drain onto the soil surface.
For each injection line a check valve been located as close as possible to the final injection point, or applicators will drain/purge the line
of any remaining fumigant prior to lifting injection shanks from the ground.
Applicators have been trained and instructed not to lift injection shanks from the soil until the shut-off valve has been closed and the
fumigant has been depressurized (passively drained) or purged (actively forced out via air compressor) from the system.
Brass, carbon steel, or stainless steel fittings must be used throughout application rigs.
Polyethylene tubing, polypropylene tubing, Teflon® tubing or Teflon® -lined steel braided tubing have been used for all low pressure
lines, drain lines, and compressed gas or air pressure lines and is all other tubing Teflon® -lined steel braided.
Application equipment been inspected to ensure that application rigs do not contain galvanized, PVC, nylon, or aluminum pipe fittings.
All rigs include a filter to remove any particulates from the fumigant, and a check valve to prevent backflow of the fumigant into the
pressurizing cylinder or the compressed air system.
All rigs include a flowmeter or a constant pressure system with orifice plates to insure the proper amount of fumigant is applied.
Applicators have been trained and instructed to ensure that positive pressure is maintained in the cylinder at not less than 200 psi during
the entire time it is connected to the application rig, if a compressed gas cylinder is used. (This is not required for a compressed air
system that is part of the application rig because if the compressor system fails the application rig will not be operable).
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Application rigs are equipped with properly functioning check valves between the compressed gas cylinder or compressed air system and
the fumigant cylinder.
Applicators have been trained and instructed to always pressurize the system with compressed gas or by use of a compressed air system
before opening the fumigant cylinder valve.
Before using a fumigation rig for the first time, or when preparing it for use after storage, applicators have been trained and instructed to:
0 Check the filter, and clean or replace the filter element as required.
0 Check all tubes and chisels to make sure they are free of debris and obstructions.
0 Check and clean the orifice plates and screen checks, if installed.
0 Pressurize the system with compressed gas or compressed air, and check all fittings, valves, and connections for leaks using soap
solution.
Applicators have been trained and instructed to:
0 Install the fumigant cylinder, and connect and secure all tubing. Slowly open the compressed gas or compressed air valve, and
increase the pressure to the desired level. Slowly open the fumigant cylinder valve, always watching for leaks.
0 When the application is complete, close the fumigant cylinder valve and blow residual fumigant out of the fumigant lines into the
soil using compressed gas or compressed air. At the end of the application, disconnect all fumigant cylinders from the application
rig. At the end of the season, seal all tubing openings with tape to prevent the entry of insects and dirt.
° Calibrate all application equipment and ensure that all control systems must be working properly.
Hot Gas Applications (check here if section is not applicable D )
Tarps have been installed prior to starting the application.
All delivery tubes have been placed under the tarp in such a way that they do not move during the application of methyl bromide.
The fumigant will be introduced from outside of the greenhouse.
All fittings, connections, and valves have been checked for leaks prior to fumigation and if cylinders are replaced during the fumigation
process, the connections and valves were checked for leaks prior to continuing the job.
Tree Replant (non-shank) Application (check here if section is not applicable D )
For each individual tree-site, the tree stump and primary root system have been removed and the tree hole has been backfilled with soil
before application.
The fumigant will be injected at a depth of at least 18 inches into the soil.
The wand will be cleared using nitrogen or compressed air before removing it from the soil and after the wand is cleared and removed
from the soil, the injection hole will be covered with soil and tamp or the soil will be compacted over the injection hole.
Buffer Zones
There are no difficult to evacuate sites within 1A (or Vs) miles of the application block that will be occupied during the buffer zone period.
There are no bus stops or other locations where persons wait for public transit within the buffer zone.
There are no buildings used for storage such as sheds, barns, garages, within the buffer zone that are occupied or that share a common
wall with an occupied structure.
For areas in the buffer zone that are not under the control of owner/operator of the application block, written agreement has been
obtained from occupants that they will voluntarily vacate the buffer zone during the entire buffer zone period.
For nearby agricultural areas that are in the buffer zone the owner/operator of that property provided written agreement that they, their
employees, or other persons will stay out of the buffer zone during the entire buffer zone period.
For publicly owned and/or operated areas (e.g., parks, rights of way, side walks, walking paths, playgrounds, athletic fields) written
permission has been given to include the public area in the buffer zone from the appropriate local and/or state officials.
Buffer Zones Overlap (check here if section is not applicable D )
A minimum of 12 hours has elapsed from the time the 1st application ends until the 2nd application begins.
If a structure exists within 300 feet of the buffer zone, appropriate emergency preparedness and response procedures are followed.
Certified applicator has informed handlers of the overlapping buffers and associated health protection requirements.
Personal Protective Equipment for Handlers
At least 1 air rescue device (e.g., SCBA) is on-site in case of an emergency.
All of the handler's PPE has been cleaned and maintained as required by the WPS for Agricultural Pesticides.
Hazard Communication
The application area buffer zone has been posted in accordance with the label.
Pesticide product labels and material safety data sheets are on-site and readily available for employees to review.
Recordkeeping
The owner/operator of the application block has been informed that he/she as well as the certified applicator must keep a signed copy of
the site-specific FMPs and the post-application summary record for 2 years from the date of application.
I have verified that this site-specific FMP reflects current site conditions and product label directions before beginning the
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fumigation.
Signature of certified applicator supervising the fumigation Date
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Post-Application Summary
General Application Information
Application date and time:
Application rate:
Size of application block:
Weather Conditions
Summary of the weather on the day of the application:
Summary of the weather during the 48-hour period following the fumigant application:
Soil Conditions (check here if section is not applicable D )
Soil temperature if air temperatures were above 100 degrees F in any of the 3 days prior to the application:
Tarp Damage and Repair (check here if section is not applicable D )
Location and size of tarp damage:
Description of tarp/tarp seal/tarp equipment failure:
Date and time of tarp repair:
Additional comments or other deviations from FMP (if applicable):
Tarp Removal (check here if section is not applicable D )
Description of tarp removal (if different than in the FMP):
Date tarps were cut:
Date tarps were removed:
Odor Complaints (check here if section is not applicable D )
Person filing odor complaint:
D On-site handler
D Person off-site
If off-site person, name, address, and phone number of person filing odor complaints:
Description of control measures or emergency procedures followed after odor complaint:
Additional comments:
Description of Incidents (check here if section is not applicable D )
Description of incident, equipment failure, or other emergency:
Date and time:
Description of emergency procedures followed:
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Additional comments:
Elevated Air Concentration Levels (check here if section is not applicable D )
D On-site
D Outside buffer zone
Location of elevated air concentration levels:
Date and time:
Description of elevated air concentration levels: (provide air monitoring results on next page)
Description of control measures or emergency procedures followed:
Description of deviations from FMP (if applicable):
Posting Signs
Date of sign removal:
Description of deviations from FMP (if applicable):
Other
Additional comments/notes:
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Air Monitoring Results
When Respiratory Protection is Not in Use - Sensory Irritation Experienced (check here if section is not applicable D )
Date and Time
Handler Task/ Activity
Handler Location Where
Irritation Was Observed Resulting Action
D Cease operations
D Respiratory protection
D Cease operations
D Respiratory protection
D Cease operations
D Respiratory protection
D Cease operations
D Respiratory protection
D Cease operations
D Respiratory protection
Comments
When Respiratory Protection is in Use - Direct Read Instrument Air Monitoring (check here if section is not applicable D )
Sample Type
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
DArea
DBreathing Zone
D Structure
Sample
Number
Sample
Date/Time
Handler
Task/Activity
(not
applicable for
structural
monitoring)
Handler
Location/
Structure
Location
Air
Concentration
Sampling
Method
Comments (e.g.,
sensory irritation
experienced while
wearing
respirator)
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I have verified that this post application summary reflects the actual site conditions during the fumigation and an accurate
description of deviations from the FMP (if applicable).
Signature of certified applicator supervising the fumigation Date
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