United States Prevention, Pesticides 

Environmental Protection and Toxic Substances May 2009 

Agency (7508P) 

Amended Reregistration Eligibility 

Decision for Dazomet 

 

Glossary of Terms and Abbreviations 

AGDCI Agricultural Data Call-In 

ai Active Ingredient 

aPAD Acute Population Adjusted Dose 

BCF Bioconcentration Factor 

CFR Code of Federal Regulations 

cPAD Chronic Population Adjusted Dose 

CSF Confidential Statement of Formulation 

CSFII USDA Continuing Surveys for Food Intake by Individuals 

DCI Data Call-In 

DEEM Dietary Exposure Evaluation Model 

DFR Dislodgeable Foliar Residue 

DNT Developmental Neurotoxicity 

EC Emulsifiable Concentrate Formulation 

EDWC Estimated Drinking Water Concentration 

EEC Estimated Environmental Concentration 

EPA Environmental Protection Agency 

EUP End-Use Product 

FDA Food and Drug Administration 

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act 

FFDCA Federal Food, Drug, and Cosmetic Act 

FQPA Food Quality Protection Act 

GLN Guideline Number 

IR Index Reservoir 

LC50 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/l, mg/kg, or ppm. 

LD50 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. 

LOC Level of Concern 

LOAEL Lowest Observed Adverse Effect Level 

MATC Maximum Acceptable Toxicant Concentration 

μg/g Micrograms Per Gram 

μg/L Micrograms Per Liter 

mg/kg/day Milligram Per Kilogram Per Day 

mg/L Milligram Per Liter 

MOA Mode of Action 

MOE Margin of Exposure 

MRID Master Record Identification Number. EPA’s system for recording and 

tracking studies submitted. 

3 
 

MUP Manufacturing-Use Product 

NOAEL No Observed Adverse Effect Level 

OPP EPA Office of Pesticide Programs 

OPPTS EPA Office of Prevention, Pesticides, and Toxic Substances 

PAD Population Adjusted Dose 

PCA Percent Crop Area 

PDP USDA Pesticide Data Program 

PHED Pesticide Handler's Exposure Data 

PHI Pre-harvest Interval 

ppb Parts Per Billion 

PPE Personal Protective Equipment 

ppm Parts Per Million 

PRZM/EXAMS Tier II Surface Water Computer Model 

RAC Raw Agriculture Commodity 

RED Reregistration Eligibility Decision 

REI Restricted Entry Interval 

RfD Reference Dose 

RQ Risk Quotient 

SCI-GROW Tier I Ground Water Computer Model 

SAP Science Advisory Panel 

SF Safety Factor 

SLC Single Layer Clothing 

TGAI Technical Grade Active Ingredient 

USDA United States Department of Agriculture 

USGS United States Geological Survey 

UF Uncertainty Factor 

UV Ultraviolet 

WPS Worker Protection Standard 

4 
 

Table of Contents 

Abstract.......................................................................................................................................... 9
 

I. Introduction ............................................................................................................................ 10
 

II. Chemical Overview................................................................................................................ 14
 

A. Chemical Identity................................................................................................................ 14 

B. Use and Usage Profile ......................................................................................................... 15 

C. Regulatory History .............................................................................................................. 17 

III. Dazomet Risk Assessments................................................................................................. 17
 

A. General Overview of Soil Fumigants.................................................................................. 17 

1. Human Health Risk ........................................................................................................ 17 

2. Environmental Fate, Ecological Effects and Risks ........................................................ 20 

3. Benefits........................................................................................................................... 23 

4. 2008 RED Mitigation Impacts ....................................................................................... 24 

B. Antimicrobial Risk ............................................................................................................... 26 

IV. Risk Management and Reregistration Decision ................................................................ 27
 

A. Determination of Reregistration Eligibility ......................................................................... 27 

B. Public Comments and Responses........................................................................................ 28 

C. Regulatory Position............................................................................................................. 29 

1. Regulatory Rationale...................................................................................................... 30 

a. Dazomet Soil Uses ....................................................................................................... 30 

i. Rate Reduction and Use Sites................................................................................... 30 

ii. Human Health Risk Management............................................................................. 30 

aa. Bystander Risk Mitigation............................................................................................ 32 

1. Buffer Zones ................................................................................................................. 32 

2. Restriction for Schools and Other Difficult to Evacuate Sites .................................... 53 

3. Posting........................................................................................................................... 54 

bb. Occupational Risk Mitigation ...................................................................................... 56 

1. Handler Definition ........................................................................................................ 56 

2. Handler Requirements ................................................................................................. 57 

3. Dermal Protection for Handlers................................................................................... 59 

4. Respiratory Protection for Handlers ............................................................................ 59 

5. Tarp perforation and removal ...................................................................................... 67 

6. Entry Prohibitions ........................................................................................................ 70 

cc. Other Risk Mitigation ................................................................................................... 75 

1. Restricted Use Classification ....................................................................................... 75 

2. Good Agricultural Practices......................................................................................... 77 

3. Fumigant Management Plans (FMPs) ......................................................................... 80 

4. Site Specific Response and Management .................................................................... 87 

5. Notice to State Lead Agencies..................................................................................... 94 

6. Soil Fumigation Training for Applicators and Training Information for Other Handlers
 

........................................................................................................................................... 95 

7. Community Outreach and Education Programs ........................................................ 100 

iii. Environmental Risk Management ......................................................................... 105 

2. Endocrine Disruptor Effects......................................................................................... 108 

3. Endangered Species Considerations............................................................................. 109 

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D. Conclusion ........................................................................................................................ 109 

V. What Registrants Need to Do............................................................................................. 109
 

A. Manufacturing Use Products............................................................................................. 110 

1. Additional Generic Data Requirements ....................................................................... 110 

2. Labeling for Manufacturing-Use Products................................................................... 116 

B. End-Use Products............................................................................................................. 116 

1. Additional Product-Specific Data Requirements ........................................................ 117 

2. Labeling for End-Use Products ................................................................................... 117 

Appendix A(1). Dazomet (PC Code 035602) Soil Fumigant Uses Eligible for Reregistration
 

..................................................................................................................................................... 118
 

Appendix A(2). Dazomet (PC Code 035602) Antimicrobial Uses Eligible for Reregistration
 

Appendix B. Table of Generic Data Requirements and Studies Used to Make the 

..................................................................................................................................................... 119
 

Reregistration Decision ............................................................................................................ 128
 

Appendix C. Technical Support Documents ......................................................................... 129
 

Appendix D. Bibliography....................................................................................................... 132
 

Appendix E. FMP Template ................................................................................................... 133
 

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Dazomet Reregistration Eligibility Decision Team 

Office of Pesticide Programs: Office of General Council: 

Andrea Medici 

Health Effects Risk Assessment 

Charles Smith, Risk Assessor Office of Enforcement and Compliance: 

Anna Lowit, Toxicology David Stangel 

Sherri Kinard, Residue Chemistry 

Ruth Allen, Epidemiology 

Judy Facey, Toxicology 

Shalu Shelat, Risk Assessor 

Biological and Economic Analysis Assessment 

TJ Wyatt, Senior Agricultural Economist 

Jonathan Becker, Senior Science Advisor 

Bill Chism, Senior Agronomist 

David Donaldson, Agricultural Economist, Team Leader 

Colwell Cook, Entomologist 

Nicole Zinn, Biologist 

Stephen Smearman, Economist 

Leonard Yourman, Plant Pathologist 

John Faulkner, Economist 

Nikhil Mallampalli, Entomologist 

Sunil Ratnayake, Botanist 

Environmental Fate and Effects Risk Assessment 

Mah Shamim, Branch Chief 

Faruque Khan, Senior Fate Scientist 

James Felkel, Wildlife Biologist 

Gabriel Rothman, Environmental Scientist 

Registration Support 

Mary Waller, Product Manager 

Tamue Gibson, Product Reviewer 

Kathy Monk, Senior Advisor 

Antimicrobial Risk Assessment Team 

Heather Garvie, Chemical Review Manager 

Diane Isbell, Reregistration Team Leader 

Cassi Walls, Ph.D., Chemist 

Timothy Dole, Industrial Hygienist 

Rick Petrie, Senior Agronomist, Team Leader 

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Risk Management 

Andrea Carone, Chemical Review Manager 

Steven Weiss, Industrial Hygienist, Chemical Review 

Manager 

Susan Bartow, Chemical Review Manager 

Dirk Helder, Chemical Review Manager 

Karen Santora, Chemical Review Manager 

Dana Friedman, Chemical Review Manager 

Cathryn O’Connell, Team Leader 

Eric Olson, Team Leader 

John Leahy, Senior Advisor 

8 
 

Abstract 

This document presents the Environmental Protection Agency’s (hereafter referred to as 

EPA or the Agency) amended decision regarding the reregistration eligibility of the registered 

soil and antimicrobial uses of dazomet. This follows the 105-day public comment period on the 

Reregistration 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 dazomet 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 dazomet uses are eligible for 

reregistration 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 dazomet uses fall into two basic categories, soil fumigation or 

antimicrobial use. Soil fumigation includes use on golf greens and tees, nonbearing crops, turf 

sites, ornamental sites, field nurseries, compost piles, potting soils, and strawberries and 

tomatoes in California only. Antimicrobial uses include: 1) as a treatment during the production 

of pulp and paper; 2) as a material preservative treatment paper coatings, non-food adhesives, 

epoxy flooring compounds, slurries, and high viscous suspensions; 3) as a biocide treatment used 

during petroleum operations; 4) as a biocide treatment to recirculating cooling water systems; 

and 5) as a remedial wood treatment to utility poles. 

Concurrent to EPA’s review of the soil fumigant uses of dazomet, EPA assessed the risks 

and developed risk management decisions for four other soil fumigant pesticides, including: 

chloropicrin, metam sodium/potassium, 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 potential 

economic impacts 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 dazomet from acute inhalation exposure to handlers, bystanders, and 

workers. To reduce these exposures and to address risks of concern, EPA is requiring a number 

of mitigation measures, such as buffer zones, posting, handler protection, restrictions on the 

timing of tarp perforation and removal operations, extending the entry prohibitions, restricted use 

classification (for soil uses only), mandatory good agricultural practices (GAPs), site-specific 

fumigant management plans (FMPs), emergency preparedness and response, notice to state and 

tribal lead agencies, training for applicators and handlers, and required community outreach and 

education programs. In addition the registrants have agreed to reduce the maximum rate from 

530 lbs ai/A to 425 lbs ai/A for incorporated applications except golf course greens/tees and turf 

9 
 

Mitigation 

renovation (which will remain at 530 lbs ai/A) which will directly reduce the potential risks to 

both humans and non-target organisms. The ecological risk assessment identified potential acute 

risks of concern for birds and mammals that could be exposed to unincorporated dazomet 

granules. 

The Agency also has identified potential human health risks of concern associated with the 

registered antimicrobial uses of dazomet. To reduce these exposures, the Agency is requiring a 

number of mitigation measures, including additional PPE for handlers engaged in these 

applications: pulp and paper use, cooling tower use, and metering pumps. For the epoxy flooring 

uses, the labels must be amended to reduce the amount of dazomet formulated in end use 

products. 

I. Introduction 

This amends and supersedes the document, “Reregistration Eligibility Decision for 

Dazomet,” 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 reregistration 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 

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 dazomet at EPA-HQ-2005-0128. EPA has determined that the 

modifications described herein will achieve the same protection goals for persons potentially 

exposed to dazomet but with a greater likelihood of compliance, fewer impacts on the benefits of 

dazomet use, and with less uncertainty regarding the protectiveness of the required measures. 

Please see table 1 for modifications from the 2008 RED to the 2009 amended soil fumigant 

REDs. 

Table 1. Modifications from 2008 to 2009 Amended Soil Fumigant REDs 

2008 REDs 2009 Amended REDs 

Buffer Zones Buffer zones based on 

available data 

New chloropicrin data support smaller 

buffers and increased confidence in safety 

New dazomet data support larger buffers 

10 
 

Mitigation 

 

2008 REDs 2009 Amended REDs 

Buffer Credits Credits allowed based on 

available data; capped at 

50% 

New data support additional credits and an 

increase in the cap to 80% for chloropicrin 

and methyl bromide, 80% for metam 

sodium and metam potassium, and 40% 

for dazomet. 

Structures within 

Buffer Zones 

Monitor with devices 

before reentry 

Monitor for sensory irritation before 

reentry 

Rights of Way Permission from local 

authorities must be granted 

if buffers extend onto 

rights of way 

Permission from local authorities is only 

required when a sidewalk or permanent 

walkway is present 

Buffer Overlap Buffers may not overlap Buffers may overlap; separate applications 

by 12 hours and increase emergency 

preparedness and response measures 

Restriction for 

Difficult to Evacuate 

Sites 

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 

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 

Posting Posting required at buffer 

zones points of entry, 

where people are likely to 

approach, and areas 

between these locations 

The posting requirement is retained but no 

longer requires areas between the entry 

areas to be posted 

Information required on the signs has been 

simplified to encourage reuse of signs 

Handler Protection Described tasks that may 

only be performed by 

handlers and situations 

when 2 handlers were 

required to be present 

while in the buffer zone 

Tasks that may only be performed by 

handlers have been updated and clarified 

The situations have been clarified 

requiring one handler supervised by a 

certified applicator to be present based on 

the chemical properties of the different soil 

fumigants, and current label statements 

Respiratory 

Protection 

Required monitoring 

devices to trigger 

additional measures 

Allow sensory irritation properties to 

trigger additional measures for MITC and 

chloropicrin 

Monitoring with devices is still required to 

remove respirators 

Monitoring with devices required for 

methyl bromide formulations with <20% 

chloropicrin 

Tarp perforation and 

removal 

Perforating tarps restricted 

to mechanical means only 

Perforating tarps by hand is allowed for 

areas less than 1 acre in size and for flood 

prevention activities 

Entry Prohibitions Entry for non-handlers is 

prohibited for the duration 

No major changes 

11 
 

Mitigation 2008 REDs 2009 Amended REDs 

of the entry restricted 

period, until tarps have 

been removed, or if 14 

days has passed 

Restricted Use The soil fumigant uses of No change 

Classification dazomet, metam-sodium 

and metam potassium, and 

MITC use for remedial 

treatment of wood poles 

and timbers are required 

to be classified as restricted 

use 

Good Agricultural 

Practices 

(GAPs) 

Certain GAPs required for 

all fumigant applications 

Some clarifications and refinements have 

been made based on stakeholder comments 

Fumigant 

Management Plans 

(FMPs) 

FMPs required to be 

completed before fumigant 

application begins and 

post-application summary 

report required following 

the application 

No major changes. Based on comments an 

example of an FMP has been included to 

illustrate how the required information 

may be presented effectively 

Emergency Response If neighbors are near Same basic measures 

and Preparedness buffers they must be 

provided with information 

or buffer zones must be 

monitored every 1-2 hours 

over 48 hours with 

monitoring devices 

Monitoring required only during peak 

emission times of the day; irritation 

detection acceptable for MITC and 

chloropicrin in lieu of devices; methyl 

bromide requires devices 

Notice to SLAs Applicators required to 

provide notice to the 

appropriate state/tribal lead 

agency before fumigating 

to facilitate compliance 

assistance and assurance 

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 

Applicator Training Certified applicators 

required to receive 

registrant soil-fumigant 

training every year 

Certified applicators required to receive 

registrant soil-fumigant training every 

three years 

Community Outreach Registrants required to Same basic requirement 

and Education develop and implement 

community outreach & 

education programs along 

with information for first 

responder in high fumigant 

use areas 

The Agency is providing information on 

where registrants are required to focus 

these efforts 

12 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

With regard to implementation timing, EPA has determined that most measures can be 

efficiently implemented via revised product labels by the 2010 use season. 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 reregistration 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 Currently 2010 2011 

Restricted Use ● ●

New Good Agricultural Practices ● ●

Rate reductions ● ●

Use site limitations ● ●

New handler protections ● ●

Tarp cutting and removal restrictions ● ●

Extended worker reentry restrictions ● ●

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 ●

○ = 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 

13 
 

 

and environmental effects; and to determine whether or not the pesticide meets the "no 

unreasonable adverse effects" criteria of FIFRA. 

Dazomet is used as a non-selective soil fumigant with fungicidal, herbicidal, and 

nematicidal properties. It is also used as an algaecide, bacteriostat, fungicide, microbiocide, 

mildewcide in a number of antimicrobial use sites. When dazomet is applied, it is quickly 

broken down into several degradates; the major degradate being methyl isothiocyanate (MITC). 

The Agency made its reregistration eligibility determination based on the required data, the 

current guidelines for conducting acceptable studies to generate such data, and published 

scientific literature. The Agency has found that currently registered uses of dazomet are eligible 

for reregistration provided the mitigation and labeling outlined in this amended RED are 

implemented. 

This document presents the Agency’s reregistration eligibility decision for the supported 

soil and antimicrobial uses of dazomet. The document consists of five sections. Section I 

contains the regulatory framework for reregistration 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 summarizes dazomet’s risk assessments as well 

as benefit and impact assessments. Section IV presents the Agency’s reregistration 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 dazomet docket (EPA-HQ-OPP-2005­

0128) at www.Regulations.gov. 

II. Chemical Overview 

A. Chemical Identity 

When dazomet is applied to soil, either to the surface or incorporated, it quickly breaks 

down. The major degradate is MITC, but formaldehyde, monomethylamine, hydrogen sulfide 

and (in acid soils) carbon disulfide, are also formed. All of these degradates are gases or volatile 

liquids which diffuse through the spaces in the soil, killing living organisms with which they 

come in contact. This reregistration eligibility decision considers risks of exposure of dazomet 

and the major degradate, MITC, as a result of dazomet applications. Table 3 provides a 

summary of the dazomet and MITC nomenclature. 

14 
 

Table 3: Dazomet and MITC Nomenclature 

Properties Dazomet MITC 

Chemical Structure 

N S 

N S 

H3C 

N 

C S 

Chemical Group Dithiocarbamate Isothiocyanate 

Common Name Dazomet Methyl isothiocyanate 

Molecular formula C5H10N2S2 C2H3NS 

Molecular Weight 162.28 73.12 

CAS No. 533-74-4 556-61-6 

PC Code 035602 068103 

Case Number 2135 Not Applicable 

B. Use and Usage Profile 

Soil Uses 

Pesticide Type: Broad spectrum soil fumigant with herbicidal, nematicidal, and 

fungicidal properties 

Target pests: Weeds, nematodes and various soil-borne pathogens 

Use patterns: Golf greens/tees, nonbearing crops (such as orchard crops, 

berries, and flower bulbs), turf sites (establishing or renovating), 

ornamental sites (establishing or renovating), field nurseries 

(establishing or renovating), greenhouses, compost piles, 

potting soils, and strawberries and tomatoes in California only 

Formulations: Granular 

Methods of 

Application: 

Tractor drawn spreaders and handheld equipment such as belly 

grinders and push-type spreaders 

Application Rates: Maximum application rate for incorporated applications is 530 

lbs ai/acre and for surface applications is 265 lbs ai/acre 

15 
 

 

 

 

Technical 

registrant: 

Certis USA, LLC 

Annual Usage: Approximately 15,000 pounds of dazomet are used annually1

 as 

a soil fumigant. 

Antimicrobial Uses 

Pesticide Type: Algaecide, bacteriostat, fungicide, microbiocide, mildewcide 

Target pests: Fungi, bacteria, mildew, algae 

Use patterns: Dazomet may be used in a variety of ways including: 1) as a 

treatment during the production of pulp and paper; 2) as a 

material preservative treatment for paper coatings, non-food 

adhesives, epoxy flooring compounds, slurries, and high 

viscous suspensions; 3) as a biocide treatment used during 

petroleum operations; 4) as a biocide treatment to recirculating 

cooling water systems; and 5) as a remedial wood treatment to 

utility poles. 

Formulations: Pelleted/tableted, liquid (soluble concentrate and flowable 

concentrate) solutions, water soluble packaged solids, ready to 

use solutions 

Methods of 

Application: 

Open pour (for both solid and liquid formulations), metering 

pump, and water-soluble packaged solid mixing 

Application Rates: Rates vary by application use site and method. Maximum rates 

are included in Table 4.1 of the Revised Occupational and 

Residential Antimicrobial Exposure Assessment (Walls, C. 

2/14/08) 

Technical 

registrant: 

BASF 

1 USDA Agricultural Chemical Usage 2003 Nursery and Floriculture Summary, September 2004, 

http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID=1001. 

16 
 

 

C. Regulatory History 

Dazomet, (PC code 035602) and the sodium salt, tetrahydro-3,5-dimethyl-2H-1,3,5­

thiadiazine-2-thione (PC Code 035607) are included in pesticide reregistration case number 

2135. Currently, there are 22 products registered containing dazomet and there are no active 

products registered containing the sodium salt. 

Dazomet has both agricultural and antimicrobial uses. Dazomet was first registered in 

the United States in 1967 as an algaecide, a bacteriostat, and a microbiocide in a variety of 

commercial and industrial applications such as pulp and paper mills, cooling tower waters, and 

non-food adhesives. 

In the late 1980s pre-plant soil uses of dazomet were registered. Dazomet is registered 

for use on non-bearing orchard crops, ornamentals, and turf to control plant pathogens, 

nematodes, and weeds. Unlike other soil fumigants, dazomet is applied as a dry granule and 

incorporated into the soil or applied to the soil surface and watered into the soil to activate it. 

A Phase IV data call-in (DCI) was issued for dazomet in January 1991 and included data 

requirements for ecotoxicity, toxicology, and environment fate. A follow-up DCI was issued in 

May of 1992 that included data requirements for neurotoxicity and the nature of residue in 

plants. Dazomet was also included in the October 1995 agricultural reentry data call-in. 

III. Dazomet 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 

When dazomet is applied and mixes with moist soil, it is quickly broken down into 

several products. One of these products is MITC that accounts for most of the fumigant activity. 

The main risk of concern for handlers, workers, and bystanders associated with the soil uses of 

dazomet is from acute inhalation exposure to MITC as a result of fumigant off-gassing. 

Dazomet handlers also are at risk from direct fumigant exposure during applications. The term 

handler refers to persons involved in the application of dazomet. 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. 

17 
 

 

In addition to soil use, dazomet is also used as an antimicrobial pesticide in the following 

ways: 1) as a treatment during the production of pulp and paper; 2) as a material preservative 

treatment for coatings, adhesives, epoxy flooring compounds, slurries, and high viscous 

suspensions; 3) as a biocide treatment used during petroleum operations; 4) as a biocide 

treatment to recirculating cooling water systems; and 5) as a remedial wood treatment to utility 

poles. 

Estimating exposure to fumigants is different from non-fumigant pesticides due to 

fumigants’ volatility, and thus, this 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. 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 

concentrations of 22 ppb or greater for a 1 to 8 hour time period for non-occupational 

(residential) bystanders and occupational handlers could 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 registrants. The benchmark 

concentration analysis thus supports the Agency’s toxicity endpoint. Since the study is a human 

exposure study for acute eye exposures to MITC, the standard 10X for animal to human 

extrapolation is not needed. A 10X uncertainty factor for intraspecies variability 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 without eye irritation. 

Compared to eye irritation, the systemic and respiratory effects are more serious in nature. 

Unfortunately, the available toxicity data in animals or humans do not allow a quantitative 

18 
 

 

comparison of the dose response curves of the eye, systemic, and respiratory effects to determine 

at the exact doses of 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 purse 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 regulations.gov, docket number: EPA-HQ-OPP-2005-0125]. 

While Agency scientists acknowledge that data are available to formulate a hypothesis for a 

MOA, 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 dazomet, the Agency considered multiple lines of evidence, using 

the best available information from monitoring studies, modeling tools, and from incidents. 

	 Monitoring: For the human health risk assessments completed for dazomet and the other 

soil fumigants within the group, several field-scale monitoring studies were considered. 

These studies quantify dazomet 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 dazomet 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, and 

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 

model and users manual are public domain and can be downloaded at 

http://www.exponent.com/perfum/. 

19 
 

 

	 Bystander, handler, and worker incident reports: Incidents for the soil fumigants 

generally occur at a low frequency relative to the total number of fumigant applications 

performed annually. However, when incidents occur, there are often many people 

involved. Incidents involving handlers and workers tend to occur more often than 

incidents with bystanders. 

Reconstructing incidents to examine the exact factors which 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. 

Bystander incidents have occurred both close to fumigated fields and up to two miles 

away from the fumigated field, although these types of incidents have not been reported 

specifically for dazomet. 

Based on these lines of evidence and as described in more detail in the risk assessments, 

EPA has determined that dazomet 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 where dazomet 

fumigations occur have the potential to exceed the Agency’s LOC without additional mitigation 

measures. There are also risks of concern for occupational handlers involved in dazomet 

applications and for workers who may re-enter 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 analysis 

for dazomet, refer to the documents listed below, all of which can be found in the dazomet 

docket # EPA-HQ-OPP-2005-0128 at http://www.regulations.gov: 

	 Dazomet: Updated Final Revised HED Chapter of the Reregistration Eligibility 

Decision Document (RED). (Shelat, S. et al., Dated April 30, 2009) 

	 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 (Dated May 14, 2009) 

 MITC 10X placeholder 

 Dazomet: Updated Final Revised HED Chapter of the Reregistration Eligibility 

Decision Document (RED). (Smith, C. et al., Dated June 2008) 

 Mode of Action, Eye Irritation, and the Intra-Species Factor: Comparison of 

Chloropicrin and MITC. (Lowit, A. and Reaves, E., Dated June 25, 2008) 

2. Environmental Fate, Ecological Effects and Risks 

20 
 

 

The Agency’s environmental fate and ecological effects risk assessments indicate that 

there are some concerns for non-target organisms that may be exposed to fumigants. Exposure 

to terrestrial organism such as birds and mammals could occur two ways, as either oral exposure 

to dazomet granules or by the inhalation route of exposure to the breakdown product MITC. 

Potential exposure to aquatic organisms may occur from surface runoff/leaching and/or 

volatilization and deposition of MITC in water bodies. 

Hazard 

Dazomet is considered moderately toxic on an acute oral basis to both birds (LD50 = 424 

mg/kg) and mammals (LD50 = 415 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 oral 

and inhalation toxicity data with MITC are needed for birds. 

MITC is considered very highly toxic to both fish (lowest LC50 = 51.2 ppb) and aquatic 

invertebrates (lowest LC50 = 55 ppb). 

Exposure 

Terrestrial (Dazomet and MITC) 

Direct exposure of mammals and birds to dazomet granules was estimated using the 

model T-REX, Version 1.2.3 (T-REX, 2005). T-REX was run for tomato and strawberry crops 

(also applicable to turf, ornamental and other pre-plant incorporated uses) for a single application 

of dazomet applied at the maximum rate of 530 lb a.i./A. In addition, exposure of terrestrial 

animals to the volatile degradation product MITC was evaluated using a preliminary LD50/square 

foot risk screening method. The Industrial Source Complex Short Term (ISCST3) model 

together with information about MITC emissions from a treated field was used to evaluate 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 (MITC) 

For 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 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 EECs represent the values that are expected once 

every ten years based on the thirty years of daily values generated during the simulation. 

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 

21 
 

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 dazomet, multiple scenarios were selected representing 

proposed dazomet usage areas based on geography and weather. PRZM and EXAMS models and 

relevant scenarios were used to estimate MITC estimated exposure concentrations (EECs) in 

surface water based on label information for dazomet application to tomatoes, strawberries, turf 

and ornamental trees at the highest application rate. The scenario with the highest concentration 

of MITC from dazomet applications was the California strawberry scenario. 

Risk 

Terrestrial Risk (Dazomet and MITC) 

Available dazomet toxicity studies allow the assessment of acute oral exposure of birds 

and mammals. Inhalation toxicity studies for MITC are only available for mammals. There are 

currently no studies available to estimate chronic terrestrial risks. 

The Agency’s levels of concern are exceeded for acute oral consumption of dazomet 

granular product for both mammal and bird species that are not Federally-listed as endangered or 

threatened as well as for ‘listed’ species. However, for mammal inhalation exposure to MITC all 

of the estimated risks are below the Agency’s LOC for both listed and non-listed species. The 

inhalation effects observed at levels higher than would be expected under normal use and 

assessed in mammals included both metaplasia of respiratory epithelium and lethality. There 

were no data available to assess inhalation risk to birds, and additional data is required. At the 

present time there are no registrant-submitted toxicity studies, or studies published in the open 

literature, that evaluate the toxicity of dazomet or MITC to terrestrial plants. 

Aquatic Risk (MITC) 

None of the estimated acute fish or aquatic invertebrate risks were above the Agency’s 

LOC for freshwater non-listed or listed species. However, no MITC studies are available for 

marine/estuarine organisms. For chronic risk from MITC the only data available to evaluate 

chronic effects on aquatic organisms are for freshwater invertebrates, which predict risks below 

the Agency’s LOC. However, no MITC data are available to evaluate the chronic effects on 

freshwater and estuarine/marine fish, or estuarine/marine invertebrates. All of the estimated 

risks for aquatic plants were below the Agency’s levels of concern. 

Due to the current data gaps for dazomet and 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: 

22 
 

	 Revised Environmental Fate and Ecological Risk Assessment For Dazomet. (Khan. F. 

and Felkel, J., Dated April 8, 2008) 

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 yearround because severe pest problems can be efficiently controlled. Growers benefit because crops 

grown in fumigated soil produce fewer blemished products, which translates into an increase in 

marketable yields. Fumigation can also provide benefits to growers by increasing crop 

management flexibility. This includes shorter crop rotational intervals (i.e., less time when fields 

are left fallow), improved ability to meet quarantine requirements (which are imposed when 

states or other jurisdictions require a pest-free harvested product), and consistent efficacy against 

critical pests. The magnitude of benefits depends on pest pressure, which varies over space and 

time, and the availability and costs associated with the use of alternatives. 

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 

23 
 

	 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 

 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 

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, 

24 
 

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 

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, which 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 dazomet 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 dazomet. 

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. 

25 
 

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 

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 and 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. Antimicrobial Risk 

In addition to the use of fumigants to sterilize soil before planting, there are a number of 

antimicrobial uses that the Agency has assessed in this RED. Dazomet may be used as an 

antimicrobial chemical in the following ways: 1) as a treatment during the production of pulp 

and paper; 2) as a material preservative treatment for paper coatings, non-food adhesives, epoxy 

flooring compounds, slurries, and high viscous suspensions; 3) as a biocide treatment used 

during petroleum operations; 4) as a biocide treatment to recirculating cooling water systems; 

and 5) as a remedial wood treatment to utility poles. 

All of the occupational handler risks were below the Agency’s LOC except for some 

scenarios with the following uses: preservation of epoxy flooring compounds, pulp and paper 

slimicide use, and microbe control in large water cooling systems. 

For more information on these antimicrobial uses: 

 Dazomet Antimicrobial Risk Mitigation Paper. (Garvie, H., Dated June 2008) 

 Dazomet: Revised Occupational and Residential Exposure Assessment of Antimicrobial 

Uses for the Reregistration Eligibility Decision (RED) Document. (Walls, C., Dated June 

2008) 

 Dazomet: Dietary Risk Assessment of Antimicrobial Uses for the Reregistration 

Eligibility Decision (RED) Document. (Walls, C., Dated March 2007) 

 Environmental Fate and Ecological Risk Assessment for the Reregistration of Dazomet 

(035602) and MITC (068103) – Antimicrobial Uses. (Petrie, R., Dated April 2007) 

Please refer to the RED Appendix for the complete document citations, which are also 

available in the dazomet docket (OPP-2005-0128) at www.regulation.gov. 

26 
 

 

 

 

IV. Risk Management and Reregistration Decision 

A. Determination of Reregistration Eligibility 

Section 4(g)(2)(A) of FIFRA calls for the Agency to determine, after submission of 

relevant data concerning an active ingredient, whether or not products containing the active 

ingredient are eligible for reregistration. The Agency has previously identified and required the 

submission of the generic (i.e., active ingredient-specific) data to support reregistration of 

products containing dazomet. The Agency has completed its assessment of the residential, 

occupational, and ecological risks associated with the use of pesticides containing the active 

ingredient dazomet. 

In Phase 5, the Agency published a risk mitigation options paper.2 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; 

 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 dazomet database and public comments on the Agency’s 

assessments for dazomet, the Agency had sufficient information on the human health and 

ecological effects of dazomet to make decisions as part of the reregistration process under 

FIFRA in July 2008. The Agency determined in the 2008 Dazomet RED that dazomet products 

are eligible for reregistration provided that (i) required product specific data are submitted, (ii) 

the risk mitigation measures outlined in this document are adopted, and (iii) label amendments 

2 EPA-HQ-OPP-2005-0128-0031, Risk Mitigation Options to Address Bystander and Occupational Exposures from 

Soil Fumigant Applications 

27 
 

 

 

 

are made to implement these mitigation measures, as outlined in Chapter V. Appendix A 

summarizes the uses of dazomet that are eligible for reregistration. 

The Agency’s decision takes into account the best available information on the potential 

risks and benefits of dazomet use. In reaching its reregistration decision and developing the 

dazomet mitigation proposal, EPA considered a range of factors, including: characteristics of 

bystander and other populations exposed to dazomet; hazard characteristics of dazomet 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. 

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. 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. 

The Registration Review process for dazomet and the other soil fumigants will also 

include a comprehensive endangered species assessment. Once that endangered species 

assessment is completed, further changes to dazomet labels may be necessary. 

B. Public Comments and Responses 

The Phase 3 public comment period on the preliminary risk assessments and related 

documents for dazomet lasted from July 13 through October 12, 2005. EPA-HQ-OPP-2005­

0128-0062 contains the Agency responses to Phase 3 public comments related to dazomet uses. 

EPA revised its risk assessments and developed benefits and risk mitigation options during 

Phase 4. The Phase 5 public comment period on revised risk assessments, benefits analysis, and 

risk management options took place from May 2 to November 3, 2007. Comments on issues 

which were significant to many stakeholders and directly influenced EPA's decisions are 

highlighted in this document as well as EPA's responses to those comments. The following 

documents include EPA’s responses to comments related to dazomet which may be found in the 

dazomet docket. 

 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) 

28 
 

	 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 of Fumigants. (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 dazomet RED on July 16, 2008. The Agency received requests to 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 dazomet 

RED which may be found in the dazomet 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 

29 
 

 

 

1. Regulatory Rationale 

The Agency has determined that dazomet is eligible for reregistration 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 

potentially exposed to dazomet but with a greater likelihood of compliance, fewer impacts on the 

benefits of dazomet use, and with less uncertainty regarding the protectiveness of the required 

measures. The following is a summary of the rationale for managing risks associated with the 

use of dazomet. Where labeling revisions are warranted, specific language is set forth in the 

summary table in Section V of this document. 

a. Dazomet Soil Uses 

i. Rate Reduction and Use Sites 

Rate 

The current maximum application rates for dazomet are 530 lbs ai/A for incorporated 

applications and 265 lbs ai/A for surface applications. According to the dazomet soil use 

registrant, Certis, USA LLC, the actual use rate of dazomet is usually much lower for most uses 

of dazomet. The turf and ornamental use rarely requires the maximum rate, except for golf 

course or turf renovation. For crop uses, the rate generally ranges from 200-300 lbs ai/A, 

although there are some cases where an application up to 400 lbs ai/A is needed. Therefore, the 

registrant has agreed to lower the maximum use rate of dazomet to 425 lbs ai/A for all registered 

uses except for golf course/turf renovation. The maximum rate for golf course/turf renovation 

will remain at 530 lbs ai/A. 

Use Sites 

Although current labels include instructions for dazomet’s use in greenhouses, the 

Agency was not aware of greenhouse use occurring prior to the 2008 RED and prohibited all 

dazomet use in greenhouses. The Agency received a comment citing dazomet’s use in 

greenhouses, and in light of this additional information, use in greenhouses is being retained 

provided the risk mitigation measures outlined in this document are adopted and label 

amendments are made to reflect these measures. Please refer to Table 6 for information 

regarding greenhouse buffer zones. 

ii. Human Health Risk Management 

For details on the dazomet human health risk assessment for soil uses, please refer to the 

Human Health Risk Assessments referenced in Section III of this document. These documents 

are also available in the public docket EPA-HQ-OPP-2005-00128, located on-line in the Federal 

Docket Management System (FDMS) at http://www.regulations.gov. 

30 
 

 

 

Dietary Risk 

Based on the currently registered use patterns for dazomet, dietary exposure, including 

exposure from drinking water, is not expected and no dietary risk mitigation is warranted for 

dazomet at this time. 

Bystanders, Workers, and Handlers 

The human health risk assessments indicate that inhalation exposure to bystanders who 

live and work near agricultural fields, nurseries, golf courses, and other areas where dazomet 

fumigations occur, and to handlers involved in the application of dazomet have the potential to 

exceed the Agency’s LOC without additional mitigation measures. 

To reduce the potential for exposure to bystanders, handlers, and workers and to address 

subsequent risks of concern, EPA is requiring a number of mitigation measures which include: 

 Reducing maximum application rates; 

 Clarifying use sites; 

 Buffer zones; 

 Dermal protection for handlers; 

 Respiratory protection 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 and implemented training and 

community outreach and education programs, will help reduce risk. Additionally, EPA will 

continue to work 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 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 

31 
 

MOEs. However, EPA has determined that these measures, working together, will prevent 

unreasonable adverse effects to 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 nonoccupational bystander exposure is similar to dietary exposure in that people consuming foods or 

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 site specific response 

and management, notice to state lead agencies, training, and community outreach and education, 

as well as labeling changes. 

1. Buffer Zones 

The human health risk assessments indicate bystanders may be exposed to MITC air 

concentrations, following dazomet applications, which 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 dazomet 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 

32 
 

 

believe that buffer zones along with other mitigation measures required by this decision 

described below will mitigate risks so that bystanders will not experience unreasonable adverse 

effects. 

Buffer Zone Requirements 

General Requirements in the July 2008 RED 

The 2008 dazomet RED described general buffer zone requirements for dazomet 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 0.25 miles 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 

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 

33 
 

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 commenters 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 commenters 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 dazomet 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 dazomet. 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; 

- the minimum buffer of 25 feet and maximum buffer of 1⁄2 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; 

34 
 

 

- 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 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 

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. 

35 
 

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. 

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 associated with that treatment. In addition, certified applicators must 

obtain permission from other landowners when buffers extend onto other lands. This 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 

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 

36 
 

dissipated were of concern. 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 to 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 

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. 

Buffer zone distances 

The Agency has received additional flux studies from the California Department of 

Pesticide Regulation, and the dazomet buffer zones have been revised to reflect this new data as 

well as other information received during Phase 5 comment period. Buffer zones have increased 

for surface applications of between 132 lbs ai/A and 265 lbs ai/A only. 

37 
 

 

PERFUM Model Inputs 

The major input parameters for the modeling were: 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. 

Rates 

The maximum rates for soil applications of dazomet are 425 lbs ai/A for incorporated 

applications and 265 lbs ai/A for surface applications. Since there is limited use information on 

typical dazomet rates, a range of rates was modeled. The rates used in the model included the 

maximum, along with rates at 75%, 50%, and 25% of the maximum for both surface and 

incorporated applications. 

Rates for bedded or strip applications (lb ai per treated area) were converted to broadcast 

equivalent application rate 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 untreated portion of the field. 

Assuming both fields are 10 acres, and only 50% of field in Figure 2 is fumigated, the rate per 

treated acre is 400 lbs ai/A for both Figure 1 and 2. The broadcast rate for Figure 1 is 400 lb 

ai/A but the effective broadcast equivalent rate for Figure 2 is 200 lbs ai/A. Labels may express 

rates as lbs per treated acre under the application instructions but they must identify buffer zone 

distances based on the broadcast or effective broadcast equivalent rates. 

Figure 1. Broadcast Application Figure 2. Bedded Application 

Block Sizes 

The Agency has limited information available on the size of application blocks treated in 

a given day but according to the registrants, dazomet is generally applied to a smaller number of 

acres than other fumigants, typically from 5 to 20 acres. The modeling did consider block sizes 

up to 40 acres per day for dazomet, and so based on the registrant comment the application block 

size will be limited to 40 acres for dazomet. 

38 
 

 

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. 

In the 2008 RED, the Agency had calculated all dazomet buffer zones based on a square 

application block. The Agency received comments regarding the buffer zone calculations for the 

use of dazomet on golf course fairways, as a rectangular applicator block is more representative 

of how fairways are treated. The Agency agrees that fairways should be calculated using a 

rectangular application block because it is more representative of the typical treatment for 

specific use-site. The Agency has thus calculated the buffer zones for golf course fairways 

taking into account this additional information, and more information on these buffers is located 

in the section on buffer zone distances. 

Emission Studies 

The Agency’s risk assessment for the RED includes modeling of the two main ways that 

dazomet is applied, surface or soil-incorporated. Details of these emission studies can be found 

in Appendix D of the Dazomet: Final Revised HED Chapter of the Reregistration Eligibility 

Decision Document (RED dated April 2009). 

Weather 

It is estimated that the major use of dazomet is in California and Washington. Some use 

in Michigan and Florida (or elsewhere in those regions) is also estimated. As a result, weather 

data for the following locations were included in this assessment: Bakersfield, CA; Ventura, CA; 

Flint, MI; Tallahassee, FL; Bradenton, FL; and Yakima, WA. Each modeling run used five years 

of weather (i.e., 1,825 potential application days) for each weather data set. Generally, Ventura, 

and Bradenton weather data result in the largest buffer zone distances, Bakersfield, Tallahassee, 

and Yakima data fall in the middle, and Flint data resulted in the smallest buffers. 

Target Air Concentration 

As described in the Human Health Risks section of Chapter 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 uncertainty factor for intraspecies 

extrapolation. The lowest observable adverse effect level (LOAEL) was 800 ppb and the human 

39 
 

concentration (HC) based on the no observable adverse effect level (NOAEL) from this study is 

220 ppb. 

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 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. The whole field 

distribution differs because it includes all points around the perimeter for the same period. 

Another way to consider the difference between the distributions is that maximum distance 

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 air 

concentrations and MOEs were also considered in the decision making process. 

An analysis based on a variety of PERFUM outputs was used in the buffer distance 

determinations. This involved consideration of not only the typical maximum and whole-field 

results, which are predictions of the distances at which a target concentration of concern (i.e., the 

human 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., MOEs) 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 dazomet 

use when coupled with other mitigation measures. 

Buffer Zone Distances 

The Agency has developed buffer zones distances based on application rate and 

application block size (rounding up to nearest rate and block size). These distances are 

summarized in Tables 4, 5, 6, and 7. 

For each of the soil emission studies, distances were first chosen for the rates identified in 

the risk assessment as the 100%, 75%, 50%, and 25% of the maximum rates for each application 

method, as shown by the bolded red font in the table. For example, for surface applications the 

rates were 265 lbs ai/A, 200 lbs ai/A, 132 lbs ai/A, and 66 lbs ai/A; and for incorporated 

applications the rates were 530 lbs ai/A, 400 lbs ai/A, 265 lbs ai/A, and 132 lbs ai/A. For golf 

40 
 

course fairways, buffers were calculated for rectangular application blocks of 1 and 5 acres. For 

greenhouse applications, buffers were calculated for structures sizes between 5,000 and 50,000 

square feet. For all other applications, application block sizes of 5, 20, and 40 acres were used in 

the buffer zone calculations. Distances for the other rates in the buffer zone tables were scaled 

by assuming a linear relationship between the 100%, 75%, 50%, and 25%, and maximum rates 

(e.g., distance at 37.5% rate = [distance at 25% rate + distance at 50% rate]/2 ) with some 

adjustments for whole numbers. 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 used for their development. 

Minimum and Maximum Buffer Zone Distances 

For dazomet, the largest buffer distance is 1140 for applications of 265 lbs ai/A for 

greenhouses of 50,000 square feet. Applications to larger block sizes and higher rates will be 

prohibited for dazomet. Comments from the registrants indicate that dazomet users do not apply 

to large areas at the very highest rates on current labels. 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. 

Additional buffer tables for use of dazomet in greenhouses and for golf course use have 

been added below since the 2008 RED. 

41 
Table 4: Buffer zone distances (in feet) for all dazomet soil applications except golf course fairways and g

Application Rates for incorporated applications (lbs ai/acre) 

Block 

Size 

(acres) 

425 400 390 380 370 360 350 340 330 320 310 300 290 280 270 265 

40 864 770 750 730 710 690 670 650 630 610 590 565 545 524 505 500 4

30 692 605 588 571 554 537 520 503 487 470 454 435 417 400 383 375 

20 520 440 426 412 398 384 370 356 343 330 317 305 288 275 260 250 2

15 400 343 333 323 312 302 292 281 271 261 251 242 229 219 208 200 

10 280 247 240 233 227 220 213 207 200 193 186 179 171 164 156 150 

9 256 230 222 215 210 204 198 192 186 180 173 167 159 153 146 140 

8 232 210 204 197 193 188 182 177 171 167 160 155 147 142 136 130 

7 208 190 186 179 176 172 166 162 157 153 147 142 135 131 125 120 

6 184 170 168 161 159 156 151 147 143 139 134 129 123 119 115 110 

5 160 150 147 144 141 138 135 132 128 124 120 116 112 108 104 100 

4 150 135 130 127 123 120 117 113 109 105 101 97 93 89 85 82 

3 140 117 113 110 106 102 99 95 91 87 82 78 75 70 66 64 

2 120 100 96 92 88 84 80 76 72 68 64 60 56 52 48 44 

1 or less 110 75 72 69 66 63 60 57 54 51 48 45 42 39 36 33 

Application Rates for incorporated applications (lbs ai/acre) 

Block 

Size 

(acres) 

230 220 210 200 190 180 170 160 150 140 132 130 120 110 100 90 

40 433 414 395 375 357 339 321 303 285 267 250 250 218 186 154 122 

30 323 308 293 281 268 255 242 229 215 202 188 188 164 141 117 94 

20 212 201 190 187 179 171 163 154 145 136 125 125 110 95 80 65 

15 160 149 138 133 127.7 122 117 111 105 99 92 92 82 72 62 52 

10 108 97 86 79 76.33 73.7 71 68 65 62 58 58 53 48 43 38 

9 99 89 76 68 65 63 61 59 56 54 51 49 45 41 38 34 

8 88 78 65 57 55 53 51 49 47 45 44 41 38 35 33 30 
7 78 68 54 46 44 43 42 41 39 38 37 35 33 31 30 28 

6 67 57 44 38 35 34 33 32 31 31 30 30 29 28 28 27 

5 56 45 34 25 25 25 25 25 25 25 25 25 25 25 25 25 

4 47 39 31 25 25 25 25 25 25 25 25 25 25 25 25 25 

3 38 32 29 25 25 25 25 25 25 25 25 25 25 25 25 25 

2 28 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 

1 or less 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 

Table 5: Buffer zone distances (in feet) for all dazomet soil applications except golf course fairways and greenhous

Application Rates for surface applications (lbs ai/acre) 

Block 

Size 

(acres) 

265 260 250 240 230 220 210 200 190 180 170 160 150 140 132 130 120 1

40 675 669 663 657 651 645 639 630 576 522 467 414 360 306 250 250 218 1

30 560 546 532 518 504 490 477 465 425 385 345 305 265 225 188 188 164 14

20 450 429 408 387 366 345 323 300 275 250 225 200 175 150 125 125 110 9

15 420 400 379 359 338 318 297 274 248 222 196 170 144 118 92 92 81.67 7

10 390 371 350 331 310 291 271 248 221 194 167 140 113 86 58 58 53.33 4

9 360 342 321 303 282 264 245 222 197 172 147 122 97 72 51 51 47 4

8 330 313 292 275 254 237 219 196 172 148 124 100 76 52 44 44 41 3

7 300 284 263 247 226 210 193 170 151 132 113 94 75 56 38 38 35 3

6 270 255 234 219 198 183 167 144 127 110 93 76 59 42 31 31 30 2

5 240 223 206 189 172 155 138 120 106 92 78 64 50 36 25 25 25 2

4 176 164 152 140 128 116 104 91 82 73 64 55 46 37 25 25 25 2

3 112 105 98 91 84 77 70 62 57 51 46 40 35 30 25 25 25 2

2 47 45 42 41 39 38 36 35 33 32 29 28 27 26 25 25 25 2

1 or less 35 34 34 33 32 31 31 31 29 28 27 27 26 26 25 25 25 2
Table 6: Buffer zone distances (in feet) for dazomet greenhouse applications 

Structure Size 265 lbs ai/A (100%) 200 lbs ai/A (75%) 132 lbs ai/A (50%) 66 lbs a

5000 square feet 240 180 120 

10000 square feet 360 300 210 15000 square feet 450 330 270 

20000 square feet 540 450 330 

25000 square feet 630 540 390 2

30000 square feet 720 570 450 2

35000 square feet 810 650 585 2

40000 square feet 855 720 540 

45000 square feet 900 760 600 

50000 square feet 1140 810 630 

Table 7: Buffer zone distances (in feet) for dazomet golf course fairways applications 

Application Rates for incorporated applications (lbs ai/acre) 

Block 

Size 

(acres) 

530 400 390 380 370 360 350 340 330 320 310 300 290 280 270 265 260 

5 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 

4 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 

3 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 

2 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 

1 or less 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 
 

 

 

The buffer zone distances shown in Table 7 are based on PERFUM modeling runs that 

are representative of golf course fairways where the width of the application block is 15% of the 

length of the application block. This ratio was proposed by the dazomet registrants as a typical 

representation of golf course fairways. The Agency understands that golf course fairway width 

to length ratios can vary significantly. Given these potential variations, the Agency believes that 

applicators can use the rectangular buffer zones shown in Table 6 if the width of the application 

block is less than or equal to 20% of the length of the application block. Examples have been 

provided below: 

For an application block 550 feet long by 110 feet wide: 

110 feet / 550 feet = 0.20 x 100 = 20%, so the buffers in table 6 can be used 

For an application block 700 feet long by 175 feet wide: 

700 feet / 175 feet = .25 x 100 = 25%, so the buffers in table 6 cannot be used; 

The buffers in table 4 must be used instead. 

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 which included consideration of the hazard profile of MITC, 

information from incident reports, monitoring data, stakeholder comments along with 

comprehensive analysis of results from PERFUM modeling and consideration of results using 

other models (e.g., the Fumigant Emissions Modeling System or FEMS). Each model was 

reviewed by the FIFRA Scientific Advisory Panel (SAP) in 2004 during the August and 

September meetings (http://www.epa.gov/oscpmont/sap/meetings/2004/index.htm). The 

analysis of PERFUM results considered distances at various percentiles of the whole field and 

maximum distance distributions, and predicted MOEs for various distances. The risk assessment 

characterizes additional types of analysis that were performed. EPA’s goal for risk management 

was to achieve buffer distances where associated risks were at or above target concentration 

levels at high percentiles of exposure. The following characterizes the risks associated with the 

buffer zone distances summarized in Table 8: 

•	 This table shows the various buffer distances for each rate and block size. It also shows 

the percentile for the whole and maximum distribution for each distance, as well as the 

MOE at the 95th percentile air concentration of PERFUM2. 

•	 The target MOE for dazomet is 10, and the MOEs at these distances range from about 7 

up to 20. Although the target air concentration is not below our LOC at all the distances, 

at the lowest MOE of 7, the predicted air concentration would be 28 times lower than the 

lowest observable adverse effect level (LOAEL) that is the level where the eye irritation 

effects were first observed in the human study. 

•	 Two registrant-submitted studies were used to calculate the buffers in the RED, and this 

data indicated little apparent difference in risk between the surface and incorporated 

application methods when similar rates were compared. 

•	 Flux data for surface applications was submitted by CDPR during the comment period, 

and the Agency has incorporated this new data in calculating the surface application 

45 
 

buffer distances. The new surface application buffer zone distances were calculated using 

the CDPR data because it is more conservative, and the buffer zones for the higher 

surface application rates have changed as a result. Since the Agency did not receive any 

new data for the incorporated application method, buffer zone distances for this method 

have not changed since the RED. 

•	 The use of GAPs, FMPs, and other mitigation measures required by this decision will 

contribute to an additional decrease in risk (see GAP and FMP sections). 

Example 

Table 8 shows the required buffer zone distances and corresponding PERFUM modeling 

results for the soil uses of dazomet (excluding fairway and greenhouse applications) using both 

the maximum distribution and the whole field distribution to the target concentration based on an 

MOE of 10, as well as the MOE from the air concentration outputs from PERFUM at the 95th 

percentile. The weather data selected here are from Ventura, CA, since only California has 

agricultural uses registered which typically involve larger application blocks than dazomet’s 

other soil uses. 

Focusing on the incorporated application method in the top row, using a 265 lbs ai/A rate 

on a 40 Acre block size, the buffer zone required for that application is 500 feet. The blocks 

referenced in this example are shaded in gray in Table 8. 

	 At this distance using the PERFUM model to predict both the whole field and maximum 

distributions the results indicate 91st percentile for whole field and 57th percentile for 

maximum, as shown in the next two columns in the table. 

o	 The risk level corresponding to this buffer zone distance at the 91st percentile 

whole field distribution is equivalent to saying a person at any location on the 

perimeter of the buffer zone during the 24 hour period following the fumigation 

of a specific field during a 5-year period would have at least a 91 percent chance 

of having of an exposure below the LOC (i.e., MOE of ≥10). 

o	 The risk level corresponding to the buffer zone distances at the 57th 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 57 percent chance of having of an exposure below the 

LOC (i.e., MOE of ≥ 10) for these typical use scenarios. 

	 Using the PERFUM 2 model outputs of air concentrations to predict MOEs at the 95th 

percentile, at 500 feet for these application parameters, the MOE is about 9 which is not 

significantly below the target MOE of 10. 

46 
Table 8: Dazomet’s Buffers and Risk Estimates 

Incorporated applications 

530 lbs ai/A (100%) 

Max incorporated rate 400 lbs ai/A (75%) 265 lbs ai/A (50%) 132 

Block 

Size 

(acres) 

Buffer 

Distance 

(feet) 

Percentile 

using 

PERFUM at 

MOE of 10 

MOE at 

95th 

percentile 

of 

PERFUM 2 

Buffer 

Distance 

(feet) 

Percentile 

using 

PERFUM at 

MOE of 10 

MOE at 

95th 

percentile of 

PERFUM 2 

Buffer 

Distance 

(feet) 

Percentile 

using 

PERFUM at 

MOE of 10 

MOE at 

95th 

percentile 

of 

PERFUM 2 

Buffer 

Distance 

(feet) 

P

PE

M

Whole Max Whole Max Whole Max Wh

40 1080 93 46 7 770 93 50 7 500 91 57 9 250 9

20 650 93 43 7 440 93 49 7 250 91 53 8 125 9

5 200 92 44 7 150 92 74 8 100 96 63 11 25 9

Surface applications 

265 lbs ai/A (100%) 

Max surface rate 200 lbs ai/A (75%) 132 lbs ai/A (50%) 66 

Block 

Size 

(acres) 

Buffer 

Distance 

(feet) 

Percentile 

using 

PERFUM at 

MOE of 10 

MOE at 

95th 

percentile 

of 

PERFUM 2 

Buffer 

Distance 

(feet) 

Percentile 

using 

PERFUM at 

MOE of 10 

MOE at 

95th 

percentile of 

PERFUM 2 

Buffer 

Distance 

(feet) 

Percentile 

using 

PERFUM at 

MOE of 10 

MOE at 

95th 

percentile 

of 

PERFUM 2 

Buffer 

Distance 

(feet) 

P

PE

M

Whole Max Whole Max Whole Max Wh

40 675 90 23 7 630 93 45 7 250 89 38 7 25 9

20 450 90 25 7 300 90 30 7 125 88 33 7 25 9

5 240 93 38 7 120 90 30 7 25 87 37 7 25 9

 Ventura Weather Data is used to calculate all the numbers in this table since it was one of the worst weather scenarios and for the agric

there is more use in California than Florida. 

 Shaded areas represent the numbers explained in the example above.  All values are approximate. 
The Agency believes that the buffer zone distances described above, combined with other 

risk mitigations described herein, will provide protection against any unreasonable adverse 

effects. 

Amended General Buffer Zone Requirements 

The following describes the general buffer zone requirements, as amended, for dazomet: 

	 “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 

	 To reduce the potential for off-site movement from multiple fumigated fields, buffer zones 

from multiple dazomet application blocks may not overlap UNLESS: 

o	 A minimum of 12 hours have elapsed from the time the earlier application(s) for 

which a buffer is in place end(s) until the latter application begins, and 

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. 

48 
 

 

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. 

 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, 

 The buffer zone period has ended, and; 

 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. 

49 
 

 

 

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 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 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. 

Buffer Zone Reduction Credits 

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,”3 in the dazomet 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 dazomet 

buffer zone reduction credits for: soils with high organic matter, and for soils with high clay 

content. 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). 

Soil Conditions 

3 Factors Which Impact Soil Fumigant Emissions - Evaluation for Use in Soil Fumigant Buffer Zone Credit Factor 

Approach, June 9, 2008, DP Barcode: 306857 

50 
 

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 

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 analysis4. 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 19985. See the Agency’s factors analysis for further details 

about the CHAIN_2D model6. 

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). 

4

 Cryer, S.A. (2007) Air/Soil Boundary Conditions For Coupling Soil Physics and Air Dispersion Modeling. 

Unpublished report of Dow AgroSciences LLC (Report # DN241493)

5 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. 

6

 Factors Which Impact Soil Fumigant Emissions - Evaluation for Use in Soil Fumigant Buffer Zone Credit Factor 

Approach, June 9, 2008, DP Barcode: 306857
 

51 
 

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, 

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%. 

Dazomet buffer zone credits are additive and as since only the organic content and clay 

content credits apply for dazomet, buffer zone credits will not exceed 40 percent (e.g., 40 

percent credit would apply for using > 3 percent organic content and >27 percent clay content). 

For example, if an application block is 10 acres and the applicator is planning to make an 

incorporated application of 230 lbs of dazomet per acre, the buffer distance from the look up 

tables is 108 feet. If after the applicator tests the soil and determines the soil contains greater 

than 27 percent clay content, then the buffer zone may be reduced by 10 percent. By calculating 

10 percent of 108 feet (108 feet x 10% = 10.8 feet buffer credit) and then subtracting the original 

buffer distance by the credit (108 feet – 10.8 feet = about 97 feet) the final buffer distance 

required is 97 feet. 

Other Buffer Zone Credits Considered 

Currently the dazomet label allows for use of tarps when making applications, but there is 

little information to suggest that growers are currently using tarps with dazomet. Since there is 

no information available about how dazomet reacts with tarps, and since other data for metam 

sodium suggests that standard tarps may not be very effective in trapping MITC vapors, there is 

no tarp credit for dazomet at this time. If additional tarps or other emission factor data become 

available to show the emissions from dazomet applications are decreased, the Agency will 

consider adding those to the dazomet 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 co-funded a grant with 

USDA-ARS for several flux studies in the southeastern U.S. These studies would 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.7

 These studies are scheduled to be completed in 2009 

and data from these studies will be submitted to the Agency for review. 

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 

7

 Health Effects Division Recommendations for Fumigant Data Requirements. June 2008. DP Barcode 353724 

52 
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. 

This mitigation measure has 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 care centers; 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 

blocks with buffers less than 300 feet will provide an incentive for some users to adopt loweremission 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. 

53 
	 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 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 buffer zones 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. 

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. 

54 
 

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 applicationspecific 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: 

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. The Agency is requiring registrants to 

submit proposals for these materials through the data call-ins that will accompany this 

RED. 

55 
 

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 up to 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 

-- "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 

bb. Occupational Risk Mitigation 

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 Worker Protection Standard (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 

56 
the current definition. As a result, the Agency has slightly changed the language from the July 

2008 RED so it is clear that the Agency is just clarifying the existing definition and not writing a 

new definition. 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 WPS (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, co-pilots, shovelers, 

shovel 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 

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. 

	 In addition to the above, persons outside the perimeter of the buffer zone who monitor 

fumigant air concentrations must also be trained and equipped as handlers in accordance 

with the requirements in the Worker Protection Standard (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 

57 
in fumigant handling tasks during the monitoring period, and (3) the certified applicator 

supervising dazomet applications could perform all tasks without anyone supervising them. 

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. 

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 significant 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 

requirement by specifying different requirements for different applications. EPA believes that 

these revisions accomplish the same goal as the July 2008 RED mitigation while reducing the 

burden on users. The revised language is: 

 For ground-rig applications (e.g., shank, rototiller, and spray blade), from the start of the 

application until the fumigant has stopped being delivered/dispensed into the soil (e.g., 

soil is sealed) the certified applicator must be at the fumigation site and must directly 

supervise all persons performing handling activities. 

 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 must communicate in writing to the site owner/operator and other handlers 

information necessary to comply with the label and the FMP (e.g., emergency response 

plans and procedures). 

The July 2008 RED also required that certified applicators supervising the application 

completed a registrant administered dazomet training program within the preceding 12 months 

before they applied a dazomet product. The Agency is still requiring certified applicators to 

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. 

58 
3. Dermal Protection for Handlers 

The dazomet dermal risk assessment indicated potential risks of concern for handlers for 

some scenarios. For handlers loading and applying dazomet for tractor drawn spreaders, there 

were potential risks for short term exposures assuming applications to 80 acres per day. 

According to information from the registrant in the phase 3 comments, dazomet is not typically 

applied to large acreages, but more typically applied to blocks 5-20 acres in size. The Agency is 

prohibiting applications to block sizes over 40 acres, so the short term concerns for dermal risk 

to handlers loading and applying with tractor drawn spreaders does not present unreasonable 

adverse effects. 

For intermediate term dermal risk, there are potential risk concerns for loaders and 

applicators, with MOEs below 100, the intermediate dermal LOC. MOEs for loaders range from 

13 for handlers wearing baseline PPE, up to 650 for handlers using closed systems. For 

applicators, there is only data for handlers applying with closed cabs, and the MOE is 52 for a 40 

acre field. Due to the amount of dazomet applied, and the small area it is typically applied to, it 

is not likely a single handler will be exposed to the amount assumed in the risk assessment over 

the intermediate time frame of 1 to 6 months. Current dazomet labels require handlers to wear 

double layers (coveralls over short-sleeved shirt and short pants) and chemicals resistant gloves 

to protect from dermal exposures. The Agency does not calculate risks with this level of PPE 

since there is no data to assess coveralls over short-sleeved shirt and short pants. However, since 

the current labels require this level of protection, the short-term risks were acceptable and the 

amount of dazomet exposure assumed in the intermediate term assessment are higher than would 

be expected based on dazomet’s use patterns, the Agency is requiring all handlers to wear double 

layers consisting of coveralls over short-sleeved shirt and short pants with gloves. In addition, 

handlers will have an option to reduce the dermal protection if application equipment (i.e., 

enclosed cabs) that provides dermal protection is used. 

For hand held applications there are potential dermal risks of concern when making 

applications with baseline PPE. The registrants have indicated that they will not be continuing to 

support applications with hand held equipment, and labels will be amended to prohibit hand held 

equipment. 

4. Respiratory Protection for Handlers 

The Agency’s human health risk assessment for dazomet indicates that inhalation risks 

for many handler tasks exceed the Agency’s LOC for the acute exposure to the parent (dazomet) 

and MITC. In the 2008 Dazomet RED, the Agency required handlers potentially exposed to 

MITC vapors from dazomet 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 fumigant application must ensure that any handler who enters the 

59 
 

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 dazomet 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: A Case Study for the Forest Seedling Industry, dated May 13, 

2009, located in the dazomet 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 

required to help enable handlers to determine if concentrations have decreased and whether it is 

60 
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 this level was based on the detection limit of the 

currently available MITC monitoring tubes. Due to the reliability issue previously, 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. 

Respiratory Requirements 

The following procedures must be followed for all agricultural pre-plant soil applications 

of dazomet. 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. 

61 
 

	 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 6000 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. 

62 
Figure 3 provides an illustration of the requirements when handlers cease operations. 

Handler activity begins. Handlers 

are NOT wearing APRs. 

Sensory Irritation 

Certified applicator in charge 

decides to cease operations rather 

than continue with respirators. 

Handlers must stop work and 

leave application block and buffer 

zone. 

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 

Resume operations. 

63 
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. 

Resume operations without an 

APR or remove respirator. 

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 

64 
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 organiccartridges 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 dazomet 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 

details of this requirement, for example who conducts the fit-testing and medical exam and what 

the medical exam entails. Detailed responses to the general requirements are included in the 

65 
following document: SRRD’s Response to Post-RED Comments for the Soil Fumigants, dated 

May 20, 2009 located in the dazomet docket. 

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 who uses a respirator is: 

 Fit-tested and fit-checked using a program that conforms to OSHA’s requirements (see 

29CFR Part 1910.134) 

 Trained using a program that confirms to OSHA’s requirements (see 29CFR 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. Handlers must 

be reexamined by a qualified medical practitioner at least annually or if their health status or 

respirator style or 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 

66 
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 the fumigation was 

completed, 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 feasibility of 

leaving tarps down for 5 days in areas that use seepage irrigation; the difficulty implementing the 

24 hour 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 located in the dazomet docket). 

While this reduction decreases the risk to bystanders, it could increase the risk to handlers 

67 
perforating or removing tarps because more fumigant could be trapped between the soil surface 

and the tarp—currently California 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 number of days before high barrier tarps can be 

perforated. 

In the comment period EPA learned from stakeholders that leaving the tarps on for 5 days 

would pose problems for current flood prevention activities. According to the comment, for 

flood prevention fields must be properly drained. In order to ensure proper drainage tarps must 

be manually cut, soil removed, and then tarps retucked. The Agency understands that the 5 day 

requirement before tarps can be perforated and the restriction on manual tarp perforation would 

be difficult for this situation and the Agency has added language to address this situation. 

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 postRED 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 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 LOC. 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 

68 
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 off-gas before the tarp is removed. If each panel is not cut, it is not likely that necessary offgassing 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 

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 (cite respiratory protection section); 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 for Flood Prevention Activities sections below. 

	 If tarps will be removed before planting, tarp removal must not begin until at least 2 

hours after tarp perforation is complete. 

69 
 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: 

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 flood prevention activities 

 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 

of the FMP. 

	 Early Tarp Perforation for Flood Prevention Activities 

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. 

6. Entry Prohibitions 

Current dazomet labels allow reentry to the treated field by workers 24 hours after 

application. The risk assessment indicates that risks could exceed EPA’s LOC for workers 

entering fields at this time period. 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 10 to 14 days following the completion of the application. 

Due to the volatile nature of MITC and the potential for exposure to unprotected workers, 

in the July 2008 RED the Agency restricted entry into the treated area by anyone other than a 

properly trained and protected handler. This restriction differs from Restricted Entry Intervals 

70 
 

(REIs) that is currently required for most conventional pesticides where dermal exposure is the 

primary pathway of exposure. 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 some comments that 

expressed concern that extending the entry-restricted period for fumigants could prevent certain 

important activities from taking place, contrary to the comments received during earlier 

comment periods. Based on discussions with stakeholders, EPA’s review of public comments, 

and the risks identified in EPA’s risk assessment, EPA does not believe any change to the entryrestricted period is warranted. EPA’s review of comments indicates that extending the entryrestricted period to protect workers will not have a substantial impact on agricultural operations. 

Therefore, the Agency is not making any changes to this section of the July 2008 RED. The 

mitigation is listed below. 

EPA believes that risks will not exceed the Agency’s LOC 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 (Figure 5), or 

 After tarps are perforated and removed if tarp removal is completed less than 14 days 

after application (Figure 6), or 

 48 hours after tarps are perforated if they will not be removed prior to planting (Figure 7), 

or 

 5 days (120 hours) after application is complete if tarps are not perforated and removed 

until14 days after the application is complete (Figure 8). 

Figures 5, 6, 7, and 8 provide illustrations of tarp perforation/removal and entry prohibition 

mitigation required for various dazomet applications. The intervals depicted are the minimum 

that must be followed. 

71 
Figure 5. Untarped Applications 

48 hours 

Buffer Zone 

Period 

Begins 

Entry 

Restricted 

Period 

Begins 

Application 

Ends 

Buffer Zone 

Period Ends 

Entry 

Restricted 

Period Ends 

Application 

Begins 

5 days (120 hours) 

72 
Figure 6. Tarp Broadcast Applications (tarps removed before planting) 

Tarp 

Perforation 

Begins 

Buffer Zone 

Period 

Begins 

Entry 

Restricted 

Period 

Begins 

Application 

Ends 

Buffer Zone 

Period Ends 

Tarp 

Perforation 

Ends 

Entry 

Restricted 

Period Ends 

Tarp 

Removal 

Begins 

Tarp 

Removal 

Ends 

Application 

Begins 

2 hours 

48 hours 

5 days (120 hours) 

73 
Figure 7. Tarp Bed Applications (Tarps not removed before planting) 

Application 

Begins 

Buffer Zone 

Period 

Begins 

Entry 

Restricted 

Period 

Begins 

Application 

Ends 

Buffer Zone 

Period Ends 

Tarp 

Perforation 

Begins 

Tarp 

Perforation 

Ends 

Planting Can 

Begin 

Entry 

Restricted 

Period Ends 

48 hours 

48 hours 

5 days (120 hours) 

74 
 

Figure 8. Tarp Bed/Broadcast Applications (Tarps are not perforated until 14 days after 

application) 

Application 

Begins 

Buffer Zone 

Period 

Begins 

Entry 

Restricted 

Period 

Begins 

Application 

Ends 

Buffer Zone 

Period Ends 

Entry 

Restricted 

Period Ends 

Tarp 

Perforation 

& Planting 

5 days (120 hours) 

48 hours 

14 days 

cc. Other Risk Mitigation 

Below are requirements for FMPs, GAPs, emergency preparedness and response, notice 

to state lead agencies, training, and community outreach and education that the Agency 

concludes are needed to mitigate risks and the likelihood of incidents caused by human error, 

equipment failure, and weather events such as temperature inversions. 

1. Restricted Use Classification 

All soil fumigant products containing methyl bromide, 1,3-dichloropropene (1,3-D), 

iodomethane, and chloropicrin are currently classified as RUPs. Soil fumigant products 

containing dazomet and metam sodium/potassium are currently unclassified. However, MITC, 

the byproduct of dazomet and metam sodium/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 

75 
 

other evidence (as specified in 40 CFR 152.170(d)) including the 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 dazomet (mostly toxicity categories III and IV. While the product toxicity of 

dazomet does not meet the hazard criteria for classification as restricted use, the degradate 

product of MITC, that 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 fumigants 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 risk 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 

fumigants safely and accurately (e.g., compaction rig, tarp equipment, and self-contained 

breathing apparatus). To apply soil fumigants safely and ensure bystanders and applicators are 

not adversely affected, handlers also need specialized competencies. 

In sum, dazomet meets the standard for restricted use because: 

 The application of 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 dazomet soil fumigant products must be classified 

as restricted use. Label requirements will include the following, which is also contained in Table 

9. This requirement has not changed from the July 2008 RED. 

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.” 

76 
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 

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 dazomet. 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 Reregistration 

Division’s response to comments document. Based on the comments, the Agency has revised 

some of the GAPs. 

The GAPs outlined in the RED and this RED amendment have been shown to reduce 

emissions and bystander exposures and will continue to be mandatory label requirements. Buffer 

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, 

77 
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. 

The following are mandatory GAPs that already appear on dazomet product labels. Some 

of the measures have been updated to clarify the language and be consistent among the fumigant 

chemical product labels. 

 Do not use dazomet when the soil temperature is extremely high (over 90 F at 2”deep). 

 Do not apply dazomet if ambient air temperature exceeds 103 F. 

 Do not apply within 3-4 feet of growing plants or closer than the drop line of trees and 

large shrubs. If slopes are treated with this product, take precautions to prevent the 

chemical from washing downward to growing plants. 

	 The area intended for treatment should be in seedbed condition with a fine tilth, free of 

clods. Do not apply dazomet to dry or improperly tilled soil. Repeated cultivation before 

treating will improve control of perennial weeds. Ditching around the site will prevent 

weed seeds, nematodes, and fungi from washing into the treated area and contaminating 

it. 

	 For optimal effect, the soil to be fumigated must have sufficient moisture for good plant 

growth (at least 50% field capacity) for 5-14 days (depending on temperature) before the 

treatment. 

	 After application, the soil must be kept uniformly moist for 5-7 days. As soon as possible 

after incorporation, the soil must be sealed to retain the concentration of gases in the soil 

which can be achieved by: 

o	 Compacting the soil surface after incorporation with a roller attached behind the 

compacting implement. 

o	 Moistening the surface after incorporation so a crust forms. 

o	 Lightly moistening the soil on the third and fourth days after treatment in case the 

weather dries out the soil surface to avoid surface cracks. 

o In difficult situations best results may be obtained by tarping the treated area. 

 Do not store dazomet in an open spreader overnight. 

 Do not apply dazomet when wind may cause granules to drift from target area. 

 Do not apply dazomet through any type of irrigation equipment. 

 Before using dazomet be aware that the three most critical factors for a successful 

fumigation program are: soil preparation, soil temperature, and soil moisture. 

Weather Conditions 

78 
 

The Agency is concerned with off gassing occurring during temperature inversion. In 

many reported incidents, a temperature inversion is often given as a potential contributing factor. 

To address this concern in the 2008 RED, the Agency prohibited applications during periods of 

temperature inversion, or when the wind speed is less than 2 mph, which can sometimes be an 

indication an inversion is occurring. In addition, the Agency provided additional information on 

the label as guidance to applicators in determining if an inversion exists. 

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. In summary, EPA has determined that 

applicators must (1) check the weather forecast and make a decision whether to proceed with a 

planned fumigation, based on conditions that are predicted, (2) only begin a fumigant application 

if wind speed is a minimum of 2 mph at the start of the application or forecasted to reach at least 

5 mph during the application, and (3) not fumigate if there will be a persistent low-level local 

inversion or an air stagnation advisory is in effect. EPA believes advisory language providing 

more detailed information on how to identify inversions and adverse weather conditions will 

increase the likelihood that applicators will proceed with applications only when weather 

conditions are or are forecast to be favorable for safe fumigations. See below and the label table 

in Section V of this document for label statements. 

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 

2008 RED since they provide additional clarity that will enhance users’ ability to practically 

comply with the requirements. The revised statements are stated below. 

79 
 

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. 

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. 

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. 

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. 

All measurements and other documentation planned to ensure that the mandatory label 

requirements are achieved must be recorded in the FMP and/or the post application summary 

report. 

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 

80 
 

Association8 (i.e., through “Administrative” and “Workplace” controls). The Centers for Disease 

Control provides guidance for developing health and safety plans in agricultural settings.9 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 

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.10 

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 

8 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)

9

 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

d001600/d001571/d001571.html

10 United States Department of Labor, Occupational Safety and Health Administration (2008) Lookback Reviews 

available at http://www.osha.gov/dea/lookback.html 

81 
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. 

Several comments from industry and user stakeholders expressed concern that FMP 

requirements would increase paperwork burden without providing 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 dazomet. 

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 days 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. 

82 
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 

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 label tables. 

Each site-specific FMP must contain the following elements: 

 Applicator information (name, phone number, license number, employer name, employer 

address, date of completing registrant dazomet 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 nonoccupied), locations of posted signs for buffers, and sites requiring 1⁄4 or 1⁄8 mile buffer 

zones (e.g., schools, 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) 

83 
 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) 

 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 (lb 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, complaints or 

elevated air concentration levels outside buffer zone suggesting potential problems, or other 

emergencies). 

 Posting procedures (person(s) who will post signs, location of posting signs, procedures for 

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 

84 
 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. 

 Air monitoring 

 For buffer zone monitoring: 

 Name, address, and phone number of handler to perform monitoring activities 

 Location and timing of monitoring for the buffer zone 

 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 documentation to ensure GAPs are achieved (e.g., measurement of 

soil and other site conditions) 

 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 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: 

85 
	 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. 

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 

86 
 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 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 dazomet soil applications: 

	 http://www.cardinalproproducts.com/Misc/FMP%20Version%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 in 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. 

87 
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 

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 

88 
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 products through chemigation to provide written notice to the county public health 

agency and to every individual or household within 1⁄4 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 

89 
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 

measure is intended to ensure protection in places people may be found. Whether measures are 

required depends on the size of the buffer zone and how close land (e.g., residential properties 

and businesses) not within the control of the owner/operator of the application block 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) to 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, EPA has included an exception for application 

blocks so fields with the smallest required buffer (25 feet) which would not be subject to this 

requirement, since they are most likely using lower application rates, applying to smaller areas, 

and/or using lower emission 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. Several of these 

comments noted concerns with the reliability of such devices at low concentrations. 

Stakeholders felt the inherent warning properties of chloropicrin and MITC (i.e., eye irritation) 

were better indicators of exposure than available devices. 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 

90 
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. 

While 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, 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 the 

MITC generating chemicals and chloropicrin 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 to increase flexibility in how a grower may 

comply with these measures as well as the effectiveness of the option to provide 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 

91 
When are Emergency Preparedness and Response Measures Needed? 

If the buffer zone is: 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: 

25 feet < Buffer ≤ 100 feet 50 feet 

100 feet < Buffer ≤ 200 feet 100 feet 

200 feet < Buffer ≤ 300 feet 200 feet 

Buffer > 300 feet or buffer zones 300 feet 

overlap 

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 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: 

 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. 

92 
 

 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 one week prior to the fumigant application in a specified field. If after four 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: 

	 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 and the buffer zone 

or residents of the dotted house must be provided emergency response information. 

	 The location of the cross-hatched house would not prompt any action. 

Figure 9. Example Site Map for Informing Neighbors 

93 
Treated field 

Buffer zone 

45 ft 

288 ft 

125 ft 

100 ft 

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 

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, 

94 
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: 

 Applicator and property owner/operator contact information (name, telephone number, 

and applicator license number) 

 Location of the application block(s) 

 Name of fumigant(s) products(s) applied including EPA Registration number 

 Time period in which fumigation may occur 

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. Soil Fumigation Training for Applicators and Training Information for Other Handlers 

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. 

95 
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 

designed 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 enhance compliance 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 

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. 

96 
 

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 dazomet 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. During the public comment period on the proposed mitigation measures and the 

post-RED 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 

97 
organizations, such as the Association of American Pesticide Control Operators, American 

Association of 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, 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 included in 

the DCI that accompanies this 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. In addition, 

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 

98 
adding a seventh training element—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. 

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 the 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/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. 

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Training Materials for Handlers 

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 Programs 

100 
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 

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 

101 
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. 

In the absence of acceptable alternative proposals, registrants will be required to provide 

information to 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 a 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., dazomet) 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 

102 
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 

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 dazomet fumigant exposure, (2) how to treat 

dazomet fumigant exposures, and (3) how dazomet 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, highuse 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). 

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Process for Identifying High-Use Fumigant Areas: 

Identifying high-use areas for dazomet 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 dazomet have been identified by the 

Agency using EPA proprietary data. Second, the high-use counties for dazomet within those 

states must be identified. The second step, identifying high-use counties, will be the registrant’s 

responsibility, using the process defined below. 

	 Step 1: Identifying States with High Use of Dazomet: The Agency is defining states with 

high usage of dazomet as those states where, on average, more than 100,000 lbs of 

dazomet are applied annually. To determine those states where, on average, more than 

100,000 lbs of dazomet has been applied annually, the Agency obtained data on the 

average number of pounds of dazomet 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 dazomet docket at EPA-HQ-OPP-2005-0128. 

	 Step 2: Identifying Counties with High Use of Dazomet: 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 dazomet may be high. Because county-level fumigant usage data is 

not publicly available and EPA proprietary data are not appropriate for this level of 

specificity, crop acreage should be used as a surrogate indicator for fumigant usage. Crop 

acreage can be obtained for major use sites of dazomet from the publicly available 2007 

USDA Census of Agriculture. Crop acreages for each of the major use sites for dazomet 

should be obtained for each the major use sites for dazomet 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 100,000 lb of dazomet applied annually. Given 

the low usage rates of dazomet at this time, the requirement for community outreach and first 

responder training programs will not likely be triggered. However, the Agency could review this 

issue during registration review to determine of dazomet usage has changed, such that 

community outreach and first responder training programs are determined to be necessary. 

Example Identifying High-Use Fumigant Areas for Metam Sodium in California: 

To help explain the process for identifying high-use fumigant areas for dazomet the 

Agency is providing the following example, which identifies the high-use counties for the soil 

fumigant, metam sodium, usage in California. 

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	 Step 1: Identify States with High Use of Metam Sodium: 

o	 Based on its analysis of proprietary data, the Agency has identified the following 

high-use states for metam sodium: 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 sodium. The same 

process would be applied to other high-use states. 

	 Step 2: Identify the Counties in California with High Use of Metam Sodium: 

o	 EPA has identified the following as the major use sites of metam 

sodium/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 sodium 

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 and supporting documentation located in the 

dazomet docket at EPA-HQ-OPP-2005-0128) 

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 and supporting 

documentation located in the dazomet docket at EPA-HQ-OPP-2005-0128) 

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. 

iii. Environmental Risk Management 

In the July 2008 RED, EPA addressed the concerns about both aquatic and terrestrial 

risks 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. 

105 
The July 2008 RED discussed exposure to terrestrial organisms such as birds and 

mammals, which could occur two ways, as either oral exposure to dazomet granules or by the 

inhalation route of exposure to the breakdown product MITC. Potential exposure to aquatic 

organisms may occur from surface runoff/leaching and drift (wind) of MITC. 

The risk assessment also identified potential acute risks of concern for birds and 

mammals, since it is assumed they could be exposed to unincorporated dazomet granules. There 

are uncertainties about the aquatic risks since there are no toxicity data available. Additional 

eco-toxicity data are required for both dazomet and MITC. 

Since dazomet is applied as a granular and watering in is required in order to activate the 

product, the amount of dazomet granular left on the soil surface to which birds and mammals 

could have access is not estimated in this assessment. It is likely the amount of dazomet actually 

available to birds and mammals is less than assumed in the risk assessment due to watering in. 

In addition, the registrants will lower the maximum rate for dazomet from 530 to 425 lbs 

a.i./A for all use sites, except for golf-course renovation. This rate reduction will also reduce the 

potential for effects on non-target organisms. In addition, the structure of the buffer zones 

required in this decision encourages growers to use the lowest rate and block size feasible in 

order to establish the smallest possible buffer zone distance for an application. Although this 

mitigation measure does not directly reduce the potential risk to ecological organisms, it does 

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 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 dazomet’s most important route of dissipation, EPA 

required the following language in the July 2008 RED taking these factors into consideration: 

“While dazomet and its 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, “Dazomet has 

certain properties and characteristics in common with chemicals that have been detected in 

groundwater (dazomet is highly soluble in water and has low adsorption to soil).” 

106 
 

 

The July 2008 RED also included language required for both tarped and non-tarped 

dazomet applications to minimize potential for leaching or runoff. During the post-RED 

comment period commenters stated that the following language was not clear or enforceable: 

“For untarped applications of dazomet, 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 Wang11. 

b. Dazomet Antimicrobial Uses 

The Agency received comments on the RED for antimicrobial uses of dazomet. A 

summary of the risk mitigation measures for the antimicrobial uses of dazomet is presented 

below; for further information on the antimicrobial risk assessment and mitigation, please see 

these documents in the dazomet docket: 

	 Dazomet: Revised Occupational and Residential Exposure Assessment of 

Antimicrobial Uses for the Reregistration Eligibility Decision (RED) Document. 

(Walls, C., Dated June 4, 2008) 

 Risk Mitigation Measures and Updated Label Language for the Antimicrobial Uses 

of Dazomet (PC Code 035602) for the Reregistration Eligibility Decision Document. 

(Garvie, H., Dated June 2 2008) 

All of the dazomet antimicrobial uses are for occupational applications. These uses 

include: 1) a treatment during the production of pulp and paper; 2) a materials preservative 

treatment for paper coatings, non-food adhesives, epoxy flooring compounds, slurries, and high 

viscous suspensions; 3) a biocide treatment used during petroleum operations; 4) a biocide 

treatment used in recirculating cooling water systems; and 5) a remedial wood treatment to utility 

poles. 

Risks of Concern 

All of the occupational handler inhalation, dermal and total MOEs were above the target 

MOE of 100 (short-term and intermediate-term) except for the following scenarios: 

11 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. 

107 
 Intermediate-term dermal exposure resulting from the preservation of epoxy 

flooring compounds via solid open pour methods: MOE = 58 

 Intermediate-term total exposure resulting from the preservation of epoxy flooring 

compounds via solid open pour methods: MOE = 55 

 Intermediate-term dermal exposure resulting from pulp and paper slimicide use 

via solid open pour methods: MOE = 79 

 Intermediate-term total exposure resulting from pulp and paper slimicide use via 

solid open pour methods: MOE = 74 

 Intermediate-term inhalation exposure resulting from the maintenance dose of 

microbe control in large water cooling system via metering pump: MOE = 98 

 Intermediate-term total exposure resulting from the maintenance dose of microbe 

control in large water cooling system via metering pump: MOE = 55 

Risk Mitigation Measures 

	 For epoxy flooring open pour scenario- labeling language must state that the product 

is not to exceed 3,500 ppm (maximum application rate of .35%) by weight of material 

treated. 

	 For the pulp and paper solid open pour scenario – update PPE language to state that 

long sleeve coveralls will be required in addition to wearing long sleeved shirt, long 

pants, shoes, socks, goggles or face shield and chemical resistant gloves. 

	 For the cooling tower use: update personal protective equipment (PPE) language to 

state that chemical resistant gloves are necessary, in addition to goggles or face 

shield. 

	 For all scenarios that use metering pumps, chemical resistant gloves must be used. 

	 Additional label instructions for pole treatment use requiring that pre-drilled holes are 

plugged immediately after application and instructions that holes are not to be drilled 

through seasoning checks. 

The data requirements for dazomet’s antimicrobial use and label changes are found in Section V. 

2. Endocrine Disruptor 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 Disruptor 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 

108 
 

developed and vetted, dazomet 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 dazomet 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 dazomet are eligible for 

reregistration 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 Section V of this document. 

V. What Registrants Need to Do 

EPA recognizes that the extent of the mitigation needed for dazomet 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 

considering stakeholder comments largely focused on the challenges of implementing many new 

measures simultaneously, EPA has developed the following schedule: 

July 2008 Dazomet RED issued 

October 2008 Comment period closed 

May 2009 EPA responds to comments, amends RED as appropriate 

Mid 2009 EPA issues product and generic DCIs 

September 1, 2009 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. 

December, 2009 EPA reviews/approves new labeling for 2010 use season 

109 
 

 

 

 

During 2009-10 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. 

September 1, 2010 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. 

2009-2012 Registrants develop data per DCIs 

2013 EPA begins Registration Review for dazomet and other fumigants 

Labeling 

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. 

A. Manufacturing Use Products 

1. Additional Generic Data Requirements 

The generic data base supporting the reregistration of dazomet for the eligible uses has 

been reviewed and determined to be substantially complete. However, data to characterize the 

hazard of MITC, the degradate of dazomet, are not available and are necessary to confirm the 

reregistration eligibility decision documented in this RED. 

Data requirements for all dazomet uses OPPTS Guideline Number Data Requirement

Study type 

870.6200 Neurotoxicity Screening Battery – Inhalation 

(MITC) 

TOX 

870.3550 Developmental Toxicity Screening Test – 

Inhalation (MITC) 

TOX 

870.3800 Reproduction and Fertility Effects – Inhalation 

(MITC) 

TOX 

870.5550 Unscheduled DNA Synthesis in Mammalian 

Cells in Culture (MITC) 

TOX 

870.4200 Chronic/Carcinogenicity Rats – Inhalation TOX 

110 
 

 

 

 

(MITC) 

870.4200 Chronic/Carcinogenicity Mice – Inhalation 

(MITC) 

TOX 

870.6200 - Neurotoxicity Screening Battery 

Acute neurotoxicity study in rat via the inhalation route with pathological evaluation of 

the complete respiratory tract. The Agency is using single day, acute exposures in its 

consideration of buffer zones following applications of dazomet. The toxicology data available 

to inform this decision are limited to an eye irritation study in human subjects and an acute 

inhalation study in rats. The purpose of the acute study in rats was to determine the LC50, not 

for use in hazard identification for human health risk assessment. The Agency can not 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 residential areas. 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 rats via inhalation with pathological evaluation of 

the complete respiratory tract in offspring is needed for MITC. This inhalation reproductive 

toxicity study 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 residential areas. 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. The Agency is open to discussing with the registrant 

the potential for performing the new enhanced 1-generation reproductive study instead of the 

standard 2-generation study. 

870.5550 - Unscheduled DNA Synthesis in Mammalian Cells in Culture 

This study is required to complete the genetic toxicity testing battery for MITC. 

870.4200 - Chronic/Carcinogenicity in Rats and Mice 

111 
 

 

 

 

 

 

Carcinogenicity studies for MITC per se are not available; 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. 

Data requirements for dazomet’s soil uses OPPTS Guideline Number Data Requirement

Study type 

835.8100 Field Volatility from Soil ORE 

Special Avian Acute Inhalation, MITC ECO 

850.2300 Avian Reproduction, Dazomet (bobwhite quail 

and mallard) ECO 

850.1075 Acute Marine/Estuarine Fish, MITC ECO 

850.1025 Acute Marine/Estuarine Mollusk, MITC ECO 

850.1035 Acute Marine/Estuarine Shrimp, MITC ECO 

850.4225 Seedling Emergence – Tier II, MITC. ECO 

850.4250 Vegetative Vigor – Tier II, MITC ECO 

850.4400 Aquatic Plant Growth – Tier II, MITC (3 

remaining species) ECO 

850.3020 Honeybee Acute Contact, MITC ECO 

Special Community Outreach and Education Program Special 

Special Training for Applicators Supervising 

Fumigations Special 

Special Training Materials for Handlers Special 

Special Buffer Zone Posting Signs Special 

835.8100 - Field Volatility from Soil 

Volatility studies are required for dazomet’s soil uses to determine flux for modeling 

purposes of the breakdown products of dazomet, including formaldehyde. 

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. 

850.2300 - Avian Reproduction (bobwhite quail and mallard duck), Dazomet 

112 
 

 

 

 

 

 

 

These studies are needed to assess potential reproductive effects in birds from exposure 

to the parent dazomet in the granular formulation. Neither of the existing studies is able to 

provide an overall NOAEL/LOAEL needed for risk assessment. There were problems with 

mixing of the diet in both studies and the mallard study had unacceptably high embryo mortality 

in the controls between day 21 and hatch. The studies indicate the possibility of severe 

reproductive effects, particularly in the mallard study, which included effects prior to those 

identified in the controls. 

850.1075 - Acute Marine/Estuarine Fish, MITC 

The aquatic risk assessment of dazomet 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 dazomet 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 

The aquatic risk assessment of dazomet 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 II, MITC 

Dazomet is 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. The protocol 

should be modified to test using air concentrations of MITC. 

850.4250 - Vegetative Vigor – Tier II, MITC 

Dazomet is 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. The protocol 

should be modified to test using air concentrations of MITC. 

850.4400 - Aquatic Plant Growth – Tier II, MITC 

Only one of five 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 

113 
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 dazomet 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 - 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 ensure compliance with fumigant product labeling. 

Additionally, EPA believes that providing safety information to other fumigant handlers will 

help them understand and adhere to practices that will help handlers protect themselves from 

fumigant 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 who 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 36 

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 

114 
 

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 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. 

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 

115 
 

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. 

Data requirements for dazomet’s antimicrobial uses 

Chemical Manufactures Association (CMA) unit exposure data to be called in: 

 GLN 875.1200 – dermal indoor exposure 

 GLN 875.1400 – inhalation indoor exposure 

 GLN 875.1600 – applicator exposure monitoring data reporting 

 GLN 875.1700 – product use information 

Because dazomet degrades into MITC, the Agency needs MITC air concentration monitoring 

data for all enclosed facilities that utilize dazomet. 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 dazomet antimicrobial use in pulp and paper 

manufacturing. The purpose of this confirmatory study is to demonstrate that the paper 

manufacturing processes remove any residual dazomet and MITC - GLN 860.1520 

Avian acute oral LD50 data using technical MITC to bobwhite quail or mallard duck – GLN 

850.2100 

Acute estuarine fish LC50 data using technical MITC – GLN 850.1075 

Acute mysid shrimp using technical MITC – GLN 850.1035 

Acute bivalve embryo larvae using technical MITC to Eastern oyster – GLN 850.1055 

2. Labeling for Manufacturing-Use Products 

To ensure compliance with FIFRA, manufacturing use product (MUP) labeling must be 

revised to comply with all current EPA regulations, PR Notices, and applicable policies. 

B. End-Use Products 

116 
 

 

 

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 MRID numbers 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. 

2. Labeling for End-Use Products 

In order to be eligible for reregistration, registrants must amend all product labels to 

incorporate the risk mitigation measures outlined in Section IV. 

117 
Appendix A 

Appendix A(1). Dazomet (PC Code 035602) Soil Fumigant Uses Eligible for Reregistration 

Use Site Formulation Method of 

Application 

Maximum Application Rate Use 

Soil Nonbearing crops (such as orchard crops, berries, and flower bulbs), ornamental sites (establishing or renovating), field nurseries (establishing or renovating), compost piles, potting soils, and strawberries and tomatoes in California only 

Granular Tractor drawn 

spreader 

425 lbs ai/A for incorporated applications. 265 lbs ai/A for surface applications. 

Application with handprohibited. See the label table in restrictions. 

Golf greens/tees, turf sites (establishing or renovating), 

Granular Tractor drawn 

spreader 

530 lbs ai/A for incorporated applications. 265 lbs ai/A for surface applications. 

Application with handprohibited. See the label table in restrictions. 

Greenhouses Granular Tractor drawn 

spreader/ mechanical spreader 

265 lbs ai/A for surface applications. 

Application with handprohibited. See the label table in restrictions. 
Appendix A(2). Dazomet (PC Code 035602) Antimicrobial Uses Eligible for Reregistration 

Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

Materials Preservatives Slurries and high viscosity suspensions (starches, nonfood use adhesives, clay slurries, glues, coatings for paper and resin emulsions) 

Ready to use solution 1706-193 

Pump or Gravity feed 

Add 0.03-0.50% by weight based on the total formulation. Actual use levels should be determined by a test of the system. 

Soluble Pump or Gravity Add 0.01-0.11% by weight concentrate feed based on the total 

formulation. Actual use 

1448-104 levels should be determined 33753-25 by a test of the system. Flowable Pump or Gravity Add 0.5-2.5% by weight of concentrate feed the suspension or dispersion. 

Actual use levels should be 

67869-25 determined by a test of the 

system. 

Soluble concentrate 67869-46 

Pump or Gravity feed 

Add at concentration of 250 ppm to 5000 ppm to water 

Formulation Intermediate 1448-98 

Slurries and high viscosity suspensions (starches, nonfood use adhesives, clay slurries, and coatings for paper) 

Ready to use solution 1448-103 1448-395 1706-193 9386-3 

Pump or Gravity feed 

Add 0.04-0.5 % by weight based on the total formulation. Actual use levels should be determined by a test of the system. 
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

9386-28 Ready to use Pump or Gravity Add 1.67-2.5 pounds per 

solution feed 1000 gallons of material to be 

preserved. Actual use levels 

74655-1 should be determined by a 

test of the system. 

Formulation Intermediate 1448-98 

Slurries and high viscosity suspensions (starches, nonfood use adhesives, clay slurries, coatings for paper, and glues) 

Soluble concentrate 1706-195 

Pump or Gravity feed 

Add 0.04-0.1% by weight based on the total formulation. Actual use levels should be determined by a test of the system. 

Paper and pulp mill Slime control 

Ready to use solution 1448-103 1448-395 9386-3 9386-28 

Pump or Gravity feed 

Intermittent method: Add 12­20 oz per ton (dry basis) of pulp or paper for two hours every 8 hours. Continuous method: Add 5­15 oz per ton (dry basis) of pulp or paper on a continuous basis. 

Badly fouled systems initial treatment. 

Ready to use Pump or Gravity Add 5-36 oz per ton of Shock dosages are to 

solution feed finished product on a 

continuous basis. Actual use 

systems may require treatment. 

1706-193 levels should be determined 

by a test of the system. 
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

Ready to use Pump or Gravity 

feed 

0.083-0.415 lbs. per 1000 gallons of treated water. 

1706-195 Actual use levels should be 

determined by a test of the system. 

Flowable Pump or Gravity Add 0.5-2.5% by weight of Badly fouled systems 

concentrate feed the suspension or dispersion. 

Actual use levels should be 

initial treatment. 

67869-25 determined by a test of the 

system. 

67869-46 Pump or Gravity 

feed 

Add concentrations of 250­4000 ppm into make up water during the grind during the manufacturing process 

Ready to use Pump or Gravity If system is noticeably fouled, Badly fouled systems 

solution feed add product at the rate of 0.5 

to 3.0 pounds per ton of pulp 

initial treatment. 

74655-1 or paper product. Additions to 

additive system should be made directly at the rate of 0.2 to 4.0 pounds (24 to 480ppm) per 1000 gallons. Add product at the rate of 0.5-2.0 pounds per ton of pulp or paper produced. Treat the system as needed to maintain control. Additions to the additive system may be reduced to 0.2 to 2.0 pounds (24 to 240 ppm) per 1000 gallons. 
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

Construction Products: Caulking material, Concrete additives, concrete and masonry additives 

Soluble concentrate: 67869-46 

Incorporation Can be fed at concentration of 

250 to 6000 ppm either directly to the finished product or to one of the raw materials 

Coatings for paper Soluble 

concentrate: 67869-46 

Incorporation Add at concentration of 250 

to 4000 ppm into the makeup water during the grind during the manufacturing process 

Epoxy Flooring Compounds Ready to use 

solution 1448-104 

Solid open pour Water-soluble packaged solids 

0.59% a.i. by weight (0.6% product by weight of material treated X 98% a.i. in product) 

Formulation Intermediate 1448-98 

Industrial Processes and Water Systems Recirculating cooling water systems 

Ready to use solution 1448-103 1448-395 9386-3 9386-28 

Pump or Gravity feed 

Add 3.25-6.5 ounces of product to 1000 gallons of water to produce a 30-60ppm concentration initially. Add 0.5-3.25 ounces of product to 1000 gallons of water to produce a 5-30ppm concentration to maintain control. 

Soluble concentrate 

Pump or Gravity feed 

Add 16 ounces of product per each 5,000-16,000 gallons of 
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

1448-104 water in system initially to 

produce a concentration of 7.5-15ppm. Add 16 ounces of product per each 15,000­96,000 gallons of water in system to produce a concentration of 1.25-7.5ppm to maintain control. 

Recirculating cooling water systems 

Formulation Intermediate 1448-98 
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

Oilfield water treatment and water floods 

Ready to use solution 1448-103 1448-395 9386-3 9386-28 

Open Pour Add 2.1 pounds of product to 

1000 gallons of drilling fluid to produce a 2500ppm concentration initially. Add 0.30 pounds of product to 1000 gallons of drilling fluid to produce a 350ppm concentration to maintain control. 

Soluble concentrate 33753-25 

Open Pour Add 1.67 pounds of product 

to 1000 gallons of drilling fluid to produce a 200ppm concentration initially. Add 1.25 pounds of product to 1000 gallons of drilling fluid 
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

to produce a 150ppm concentration to maintain control. 

Soluble 

Add 5.22 pounds of product 

concentrate to 1000 gallons of drilling 1448-104 fluid to produce a 625ppm 

concentration initially. Add 0.73 pounds of product to 1000 gallons of drilling fluid to produce an 88ppm concentration to maintain control. For water soluble packaging: One pound per 191 gallons initially then one pound per 1363 gallons to maintain control. 

Oilfield Drilling Muds and work over or completion fluids 

Soluble concentrate 1448-104 9386-13 33753-25 

Open Pour Add 175-182 pounds of 

product to 1000 barrels of drilling fluid to produce a 500-520ppm concentration. For best results add product in a thin stream to the pit while drilling fluid is circulating. 

Ready to use Add 75 pounds of product to solution 1000 barrels of drilling fluid 

to produce a 2080-2500ppm 

1448-103 concentration. For best 9386-3 results add product in a thin 

stream to the pit while drilling fluid is circulating. 
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

 Ready to use Add 75 pounds of product to 

solution 1000 barrels of drilling fluid 

to produce a 2080ppm 

1448-395 concentration. For best 9386-28 results add product in a thin 

stream to the pit while drilling fluid is circulating. 

Wood Preservatives Utility Poles, pilings, timbers, solid and laminated wood products. 

Pelleted solid 7969-162 71406-5 1448-104 

Applied in treatment holes drilled into wood product to be treated 

Drill three 7/8 in. diameter by 14 in. long holes at a steep angle (45 deg or greater) in a spiral patter starting at ground line. Apply 70 grams of end use product into each hole. Do not overfill treatment hole. Add liquid accelerant if desired to treatment hole. Plug treatment hole with a tight fitting treated wooden dowel, removable plastic plug or other suitable cap. 

For wood in ground cstart at or slightly belbe arranged in a spiratreatment zone with abetween holes. An accelerant of a 1% napthenate in mineral treatment holes after and is designed to sperelease of the active fproduct. Keep acceleexcept when in treatmplugged immediately Not to be used indoorstructures. 

Technical Registrations Technical 

N/A N/A For use in the formula

Chemical: registrations only. 7969-161 

For use in the formulawood protectants only
Use Site Formulation Method of 

Application 

Application Rate/ No. of 

applications 

Use 

Technical chemical: 9386-10 

N/A N/A For use in the formula

registrations only 

Technical chemical: 67869-18 

N/A N/A For use in the formula

registrations only For use in the followiSystems: pulp and paFor Material Preservaviscosity suspensions adhesives, clay slurrieand resin emulsions) 
 

Appendix B. Table of Generic Data Requirements and Studies Used to Make the 

Reregistration Decision 

This section is currently not available. 

128 
Appendix C. Technical Support Documents 

Additional documentation in support of this RED is maintained in the OPP docket, 

located in room S-4400, One Potomac Yard (South Building), 2777 S. Crystal Drive, 

Arlington, VA 22202. It is open Monday through Friday, excluding legal holidays, from 8:30 

am to 4 pm. All documents, in hard copy form, may be viewed in the OPP docket room or 

downloaded or viewed via the Internet at the following site: http://www.regulations.gov 

These documents include: 

Health Effects Support Documents 

	 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, May 14, 2009 

	 Dazomet: Third Revision of the HED Human Health Risk Assessment. April 30, 2009 

	 Dazomet: Updated Final Revised HED Chapter of the Reregistration Eligibility Decision 

Document (RED). Smith, C. et al.; D354014; June 24, 2008. 

	 Mode of Action, Eye Irritation, and the Intra-Species Factor: Comparison of Chloropicrin 

and MITC. Lowit, A. and Reaves, E.; D293356; TXR 0054860; June 25, 2008. 

	 The Health Effects Division’s Response to Comments on EPA’s Phase 5 Reregistration 

Eligibility Decision Document for Dazomet. Smith, C.; D306858; June 18, 2008. 

Environmental Fate and Ecological Effects Support Documents 

	 Further Response to Public Comments on the 7/9/08 Completed Dazomet RED, 

Rothman, G. and Felkel, J. March 3, 2009 

	 Revised Environmental Fate and Ecological Risk Assessment For Dazomet. Khan. F. 

and Felkel, J.; D306855; April 8, 2008. 

	 Response to Phase 5 Public Comments on the Phase 4 Dazomet Environmental Fate and 

Ecological Risk Assessment. Khan, F., and Felkel, J.; D306854; April 2, 2008. 

Biological and Economical Analysis Support Documents 

	 Response to BEAD Related Public Comments Received on the Reregistration 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. 

129 
	 Process for Defining High-Use Fumigation Areas at the State and County Levels 

(DP#364647) May 14, 2009. 

	 Assessment of the Benefits Soil Fumigants (Methyl Bromide, Chloropicrin, MetamSodium, Dazomet) Used by Forest Tree Seedling Nurseries. (Chiri, D. and Donaldson, D. 

Dated April 19, 2007) EPA-HQ-OPP-2005-0125-0044 

	 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. (Faulkner, J., 

and Yourman, L., Dated April 20, 2007) EPA-HQ-OPP-2005-0125-0045 

	 Assessment of the Benefits of Soil Fumigation with Chloropicrin, Methyl Bromide, 

Metam-sodium, and Dazomet In Strawberry Nursery Runner Production. (Yourman, L., 

and Smearman, S., Dated April 19, 2007) EPA-HQ-OPP-2005-0125-0054 

	 Assessment of the Benefits of Soil Fumigation with Chloropicrin, Methyl Bromide, 

Metam Sodium and Dazomet in Ornamental Production. (Chiri, A., and Wyatt., T., Dated 

April 18, 2007) EPA-HQ-OPP-2005-0128-0060 

	 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 of Fumigants. (Wyatt. T., et al, Dated 

June 2008) 

Antimicrobial Assessment Support Documents 

	 Dazomet Antimicrobial Risk Mitigation Paper. Garvie, H., Dated June 2, 2008. 

	 Dazomet: Revised Occupational and Residential Exposure Assessment of Antimicrobial 

Uses for the Reregistration Eligibility Decision (RED) Document. Walls, C.; D Dated 

June 2008. 

	 Dazomet: Dietary Risk Assessment of Antimicrobial Uses for the Reregistration 

Eligibility Decision (RED) Document. (Walls, C., Dated March 2007) 

	 Environmental Fate and Ecological Risk Assessment for the Reregistration of Dazomet 

(035602) and MITC (068103) – Antimicrobial Uses. (Petrie, R., Dated April 2007) 

	 Phase 6 Response to Substantive Public Comments on Antimicrobials Division’s 

Occupational and Residential Assessments for the Reregistration Eligibility Decision 

130 
(RED) Documents for the following chemicals: Methylisothiocyanate (MITC), Metam 

Sodium, Dazomet, and Chloropicrin. Walls, C.; February 14, 2008. 

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 

	 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. 

Risk Management Support Documents 

	 SRRD’s Response to Post-RED Comments for the Soil Fumigants. Rice, M. and 

McNally, R; May 2009. 

	 SRRD’s Response to Phase 5 Public Comments for the Soil Fumigants. Rice, M. and 

McNally, R.; July 2008. 

	 Risk Mitigation Options to Address Bystander and Occupational Exposures from Soil 

Fumigant Applications. EPA-HQ-OPP-2005-0128-0031. 

131 
Appendix D. Bibliography 

This section is not currently available. 

132 
Appendix E. FMP Template (template uses MeBr soil applications as an example) 

133 
Target application date/window: Brand name of fumigant: 

 

Brand name: 

Minimum time following application that tarp will be repaired: 

Name and phone number of contact person responsible for cutting 

and/or removing tarps (if other than certified applicator): 

Schedule and target dates for cutting tarps: 

Certified Applicator Supervising the Fumigation 

Name and phone number: License number: 

 Commercial applicator 

 Private applicator 

Employer name and address: Date of completing registrant 

training program: 

General Site Information 

Application block location, address, or global positioning system (GPS) coordinates: 

Name, address, and phone number of owner/operator of application block: 

General Application Information 

EPA Registration Number: 

Tarps (check here if section is not applicable  ) 

Lot #: Thickness: 

Name and phone number of contact 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 size of damage that will be repaired: 

Other factors used to determine when tarp repair will be conducted: 

Equipment/methods used to cut tarps: 

Schedule and target dates for removing tarps: 

134 
Description of soil texture and moisture in application block: 

 

 

 

 

 

Rate from 

lookup table 

on label (lb 

ai/A): 

Credits applied: 

 high barrier film ____ % 

 organic content _____________ % 

 clay content _____________ % 

 other: _____________ % 

Total credits _____________ % 

Soil Conditions 

Description of method used to determine soil moisture level: 

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: 

 Bedded 

 Broadcast 

 Hot gas - outdoor 

 Hot gas - greenhouse 

 Hand held probes 

Block size 

from lookup 

table on label 

(acres): 

 _________ Buffer zone 

distance: 

__________ ft 

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). 

135 
 

 

 

 

 

 

If your state and/or tribal lead agency requires notice, list contacts that were notified: 

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  Fumigation Site Monitoring or Response Information for Neighbors 

If Response Information for Neighbors has been selected, completed the following: 

If buffer zone is 25-100 ft:  Neighbors within 50 ft of buffer zone  No neighbors within 50 ft of buffer zone 

If buffer zone is 100-200 ft:  Neighbors within 100 ft of buffer zone  No neighbors within 100 ft of buffer zone 

If buffer zone is 200-300 ft:  Neighbors within 200 ft of buffer zone  No neighbors within 200 ft of buffer zone 

If buffer zone is > 300 ft:  Neighbors within 300 ft of buffer zone  No neighbors within 300 ft of buffer zone 

If buffer zones overlap  Neighbors within 300 ft of buffer zone  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 

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: 

136 
Comments/notes: 

137 
 

 

 

Site Map 

Location of application block: _______________________________________________________________________________ 

Map Legend

 Application block Buffer zone Property lines Roads Right-of-way Walkway, sidewalk, path 

Sch

 NH 

NAB B WB DC Bus stop Water body Daycare facility School Nearby application block 

IPC ALF P Inpatient clinic Prison Well Nursing home Assisted living facility

138 
Handler Information 

Handler Name, Address, and Phone 

Number 

Employer Name, Address, and Phone 

Number 

Tasks They are Trained and 

Authorized to Perform 

Date of PPE 

Training 

Qu
 

If intend to cease operations - Name, address, and phone number of handler to perform monitoring 

activities prior to operations resuming: 

Air Monitoring Plan 

For Buffer Zone Monitoring: (check here if section is not applicable  ) 

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  ) 

If sensory irritation is experienced:  Intend to cease operations  Intend to continue operations with respiratory protection 

If intend to continue operations with respiratory protection, complete section for Handlers with Respiratory Protection below. 

Monitoring equipment: 

For Handlers with Respiratory Protection: (check here if section is not applicable  ) 

Representative Handler Tasks to be Monitored Monitoring Equipment Timing 

140 
Air Monitoring Plan for Methyl Bromide Formulation with < 20% Chloropicrin 

For Buffer Zone Monitoring: (check here if section is not applicable  ) 

Name, address, and phone number of person(s) to perform sampling: 

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 

141 
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 1⁄8 and 1⁄4 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  ) 

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). 



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. 

142 
_______________________________________________ ___________________________________ 

 

Before using a fumigation rig for the first time, or when preparing it for use after storage, applicators have been trained and instructed to: 

 Check the filter, and clean or replace the filter element as required. 

 Check all tubes and chisels to make sure they are free of debris and obstructions. 

 Check and clean the orifice plates and screen checks, if installed. 

 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: 

 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. 

 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  ) 

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  ) 

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 1⁄4 (or 1⁄8) 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  ) 

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 

fumigation. 

Signature of certified applicator supervising the fumigation Date 

143 
Application date and time: Application rate: 

 

 

 

Date tarps were cut: 

 

Post-Application Summary 

General Application Information 

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  ) 

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  ) 

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  ) 

Description of tarp removal (if different than in the FMP): 

Date tarps were removed: 

Odor Complaints (check here if section is not applicable  ) 

Person filing odor complaint: 

 On-site handler 

 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: 

144 
 

Description of incident, equipment failure, or other emergency: 

 

Description of Incidents (check here if section is not applicable  ) 

Date and time: 

Description of emergency procedures followed: 

Additional comments: 

Elevated Air Concentration Levels (check here if section is not applicable  ) 

 On-site 

 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: 

145 
 

 

 

 

_______________________________________________ ___________________________________ 

 

Air Monitoring Results 

When Respiratory Protection is Not in Use – Sensory Irritation Experienced (check here if section is not applicable  ) 

Date and Time Handler Task/Activity 

Handler Location Where 

Irritation Was Observed Resulting Action Comments 

 Cease operations 

 Respiratory protection 

 Cease operations 

 Respiratory protection 

 Cease operations 

 Respiratory protection 

 Cease operations 

 Respiratory protection 

 Cease operations 

 Respiratory protection 

When Respiratory Protection is in Use – Direct Read Instrument Air Monitoring (check here if section is not applicable  ) 

Sample Type 

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) 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

Area 

Breathing Zone 

Structure 

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 

146 
147