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Implementation of Risk Mitigation Measures for Soil Fumigant Pesticides

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Current as of December 1, 2008

Pesticide Soil Fumigant Chemicals

EPA Pesticide Program Update, 8/29/08
EPA News Release, 7/10/08
Mitigation Measure-Specific Fact Sheets

EPA is requiring important new safety measures for soil fumigant pesticides to increase protections for agricultural workers and bystanders – people who live, work, or otherwise spend time near fields that are fumigated. These measures are included in risk management Reregistration Eligibility Decisions (REDs) for the soil fumigants:

Although these soil fumigant decisions are final, EPA requested public comment on implementation of the risk mitigation measures by October 30, 2008 - August 29, 2008, FR Notice; July 16, 2008, FR Notice. The Agency is considering comments and new information received, at present.

On this page you will find information on a suite of complementary measures in EPA's multifaceted regulatory approach to minimize risks of these pesticides. Taken together, these measures are expected to directly reduce exposures and risks, improve safety and reduce the potential for accidents, foster compliance and reduce misuse, and enhance enforcement, while maintaining important benefits.

Background

Fumigant Properties and Uses

Soil fumigants are pesticides which, when applied to soil, form a gas to control pests that live in the soil and can disrupt plant growth and crop production. The fumigants are either volatile chemicals that become gases at relatively low temperatures, around 40 degrees Fahrenheit, or they are chemicals that react to produce such a gas (e.g., dazomet and metam sodium converting to methyl isothiocyanate or MITC). Soil fumigants are used on many crops, primarily potatoes, tomatoes, strawberries, carrots, and peppers, to control a wide range of pests including nematodes, fungi, bacteria, and weeds.

Agricultural Benefits and Human Health Risks

Because of the broad range of pests controlled, soil fumigants are used as part of the production of a wide variety of crops and provide high benefits for many growers. As gases, however, fumigants move from the soil to the air at the application site and may pose risks to workers. Bystanders, who are not involved in the fumigant application but who live, work, or are otherwise located in nearby areas, may also be exposed to airborne fumigants that move off the application site. Bystanders include agricultural workers in nearby fields who are not involved with the fumigant application.

Incidents of bystander exposure demonstrate that fumigants have the potential to move off-site at concentrations which produce adverse health effects in humans, over periods of several hours to days after application. These health effects may range from mild and reversible eye irritation to more severe and irreversible effects, depending on the fumigant and the level of exposure.

Group Review

EPA reviewed chloropicrin, dazomet, metam sodium/potassium, and methyl bromide and the soil fumigants 1,3-dichloropropene (Telone®) and iodomethane (methyl iodide) as a group. The Agency completed a RED for 1,3-dichloropropene in 1998. The newly registered fumigant iodomethane will be reexamined later this year to determine whether new mitigation or restrictions are necessary. By considering the soil fumigants as a group, the Agency has ensured that similar risk assessment tools and methods were used for all, and risk management approaches were consistent. As discussed further below, EPA plans to consider the soil fumigants together again during Registration Review, beginning in 2013.

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Risk Mitigation Measures for Soil Fumigants

EPA is requiring a suite of complementary mitigation measures to protect handlers, reentry workers, and bystanders from risks resulting from exposure to the soil fumigant pesticides.  These measures are designed to work together to address all risks, but focus on the acute human inhalation risks that have been identified in the revised risk assessments for these fumigants.

Most of the measures summarized here apply to all of the soil fumigants (for example, fumigant management plans).  See fact sheets explaining implementation of these general risk mitigation measures. However, some measures are specific to individual fumigants (for example, buffer distances).  The fumigant-specific measures are summarized in chemical-specific RED fact sheets.

Measures include:

Buffer Zones: EPA is requiring fumigant users to establish a buffer zone around treated fields to reduce risks from acute inhalation exposure to bystanders. A buffer zone provides distance between the application site (i.e., edge of field) and bystanders, allowing airborne residues to disperse before reaching the bystanders. This buffer will reduce the chances that air concentrations where bystanders are located will cause acute adverse health effects.

EPA has selected buffer distances that will protect bystanders from exposures that could cause adverse effects, but that are not so great as to eliminate benefits of soil fumigant use. The size of the buffer zones is based on the following factors:

Buffer zone distances are scenario-based using applicable site conditions and will be provided in look-up tables on product labels. EPA is also giving "credits" to encourage users to employ practices that reduce emissions (for example, use of high barrier tarps). Credits will reduce buffer distances. Some credits will also be available for site conditions that reduce emissions (e.g., high organic or clay content of soils).

Posting Requirements: For buffer zones to be effective as risk mitigation, bystanders need to be informed about the location and timing of the fumigation to ensure they do not enter areas designated as part of the buffer zone. EPA is requiring that buffer zones be posted at usual points of entry and along likely routes of approach to the buffer unless:

  1. a physical barrier such as a fence prevents access to the buffer, or
  2. all of the area within 300’ of the buffer is under the control of the owner/operator.

The signs must include a “do not walk” symbol, date and time of the fumigation, date and time the buffer restrictions expire, fumigant product name, and contact information for the fumigator.

Agricultural Worker Protections: Persons engaged in any of a number of activities which are part of the fumigation process are considered “handlers.”  Handler activities include operating fumigation equipment, assisting in the application of the fumigant, monitoring fumigant air concentrations, and installing, repairing, perforating, and removing tarps.

Applicator and Handler Training Programs: EPA is requiring fumigant registrants to develop and implement training programs for applicators in charge of soil fumigations on proper use and good agricultural practices so these applicators are better prepared to effectively manage fumigant operations. The registrants also must prepare and disseminate training information and materials for fumigant handlers (those working under the supervision of the certified applicator in charge of fumigations). Providing safety information to other fumigant handlers will help them understand and adhere to practices that will protect them from risks of exposure. The training programs must include elements designed to educate workers regarding work practices that can reduce exposure to fumigants, and thereby improve safety for workers and bystanders.

Good Agricultural Practices: Current fumigant labels recommend practices that help reduce off gassing and improve the safety and effectiveness of applications.  The Agency has determined that including certain practices on labels as requirements rather than recommendations will minimize inhalation and other risks from fumigant applications.  Several fumigant products already incorporate some of these measures on their labels.  Examples of good agricultural practices include proper soil preparation/tilling, ensuring optimal soil moisture and temperature, appropriate use of sealing techniques, equipment calibration, and weather criteria.

Application Method, Practice, and Rate Restrictions: The Agency is restricting certain fumigant application methods and practices for which data are not currently available to determine appropriate protections, or that lead to risks that are otherwise difficult to address. These include certain untarped applications for some fumigants. EPA is also lowering maximum application rates to reflect those rates needed for effective use, thereby reducing the potential for inhalation exposure and risk.

Restricted Use Pesticide Classification: All soil fumigant products containing methyl bromide, 1,3-dichloropropene, and chloropicrin are currently restricted use pesticides, but many soil fumigant products containing metam sodium/potassium and dazomet are not restricted use pesticides.  The Agency has determined that all of the soil fumigants undergoing reregistration meet the criteria for restricted use.  Therefore, EPA will reclassify metam sodium/potassium and dazomet as restricted use pesticides.

Site-Specific Fumigant Management Plans (FMPs): Soil fumigations are complex processes involving specialized equipment to properly apply volatile and toxic pesticides. EPA's risk mitigation allows for site-specific decisions to address the specific conditions where the fumigant is applied. To address this complexity and flexibility, EPA is requiring that fumigant users prepare a written, site-specific fumigant management plan before fumigations begin. Written plans and procedures for safe and effective applications will help prevent accidents and misuse and will capture emergency response plans and steps to take in case an accident occurs.

FMPs will be a resource for compliance assurance; fumigators will capture in the FMP how they are complying with label requirements. FMPs will help ensure fumigators successfully plan all aspects of a safe fumigation, and will be an important tool for federal, state, tribal, and local officials to verify compliance with labeling.

Elements that must be included in soil Fumigant Management Plans are:

The certified applicator supervising the fumigation must verify in writing that the FMP is current and accurate before beginning the fumigation. A post-fumigation summary report describing any deviations that may have occurred from the FMP will also be required within 30 days of the end of the application.

The fumigator and the owner/operator of the fumigated field must keep the FMP and post-fumigation summary report for two years and make them available upon request to federal, state, tribal, and local enforcement officials.

Emergency Preparedness and Response Requirements: Although 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. Early detection and appropriate response to accidental chemical releases is an effective means of reducing risk. Preparedness for these types of situations is an important part of the suite of measures necessary to avoid risks posed by fumigants.

Notice to State and Tribal Lead Agencies: Assuring compliance with new label requirements is an important part of the package of mitigation measures. Therefore, before the application, fumigators must notify State and Tribal Lead Agencies for pesticide enforcement about applications they plan to conduct. This information will aid states in planning compliance assurance activities.

Community Outreach and Education Programs: EPA is requiring fumigant registrants to develop and implement community outreach programs, including programs for first responders, to ensure that information about fumigants and safety is available within communities where soil fumigation occurs. Outreach and information will address the risk of bystander exposure by educating community members about fumigants, buffer zones, how to recognize early signs of fumigant exposure, and how to respond appropriately in case of an incident.

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Next Steps

Final Decision for Comment: After consulting with stakeholders and obtaining public input through the Agency's pesticide public participation process, EPA has made final decisions on the soil fumigants. Although the decisions are final, due to the broad scope and complexity of the decisions, EPA requested input on implementation approaches during an extended public comment period that ended October 30, 2008 - August 29, 2008, FR Notice; July 16, 2008, FR Notice. At present, EPA is considering new information received during the comment period and may refine plans for implementation of the risk mitigation measures, as needed.

Registration Review: 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, new technologies to reduce emissions are emerging. EPA plans to move the soil fumigants forward in Registration Review, from 2017 to 2013. This will allow EPA to consider new data and technologies sooner, determine whether the mitigation included in this decision is effectively addressing the risks as EPA believes it will, and to include other soil fumigants that are not part of the current review.

Timeline for Next Steps:

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For More Information:

Soil Fumigant Dockets: REDs, RED fact sheets, and supporting information for these decisions are available in the following individual soil fumigant dockets at Regulations.gov.

Fumigant REDs and RED Fact Sheets: Are also available on the Pesticide Reregistration Status Web page.

Mitigation Measure-Specific Fact Sheets:

EPA Soil Fumigant Contacts:

Steven Weiss (weiss.steven@epa.gov)
Methyl Bromide Chemical Review Manager
703) 308-8293

Andrea Carone (carone.andrea@epa.gov)
Chloropicrin Chemical Review Manager
1,3-Dichloropropene Chemical Review Manager
(703) 308-0122

Dirk Helder (helder.dirk@epa.gov)
Metam Sodium/Potassium Chemical Review Manager
(208) 378-5749

Heather Garvie (garvie.heather@epa.gov)
Methyl Isothiocyanate (MITC) Chemical Review Manager
(703) 308-0034

Cathryn OConnell (oconnell.cathryn@epa.gov)
Dazomet Chemical Review Manager
(703) 308-0136

John Leahy (leahy.john@epa.gov)
Senior Advisor
(703) 305-6703

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