Soil Fumigants

Implementing Safety Measures

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Risk Mitigation (Safety) Measures for Soil Fumigants

EPA now requires a suite of complementary safety 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 (to view these risk assessments go to the Soil Fumigant Chemicals page, find the chemical of interest to you and click on the "Information on..." link; then on that page, click on the docket tab).

Most of the measures summarized here apply to all of the soil fumigants (for example, fumigant management plans). However, some measures are specific to individual fumigants (for example, buffer distances). The fumigant-specific measures are explained in detail in the chemical-specific Amended REDs, found on the soil fumigant chemicals page.

Measures include:

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Buffer Zones

EPA now requires fumigant users to establish a buffer zone around treated fields to reduce risks 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 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:

  • application rate;
  • field size;
  • application equipment and methods; and
  • emission-control measures (e.g., tarps).

Buffer zone distances 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).

Buffer zone fact sheet.

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Posting Requirements 

For buffer zones to be effective, bystanders need to be informed about their location to ensure they do not enter areas designated as part of the buffer zone. EPA now requires that buffer zones be posted at usual points of entry and along likely routes of approach to the buffer unless a physical barrier prevents access to the buffer. The signs must include a “do not walk” symbol, fumigant product name, and contact information for the fumigator.

Posting requirements fact sheet.

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Agricultural Worker Protections

Persons engaged in any of a number of activities that 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.

Respiratory Protection: Most soil fumigant labels require handlers to either stop work or put on respirators if they experience sensory irritation. In most cases inhalation risks can be mitigated (that is, potential for harm can be reduced) with the use of air purifying respirators if they choose to continue working after experiencing sensory irritation.

For scenarios involving very high air concentrations where these respirators do not provide adequate protection, EPA now requires handlers to stop work and leave the area. If there is an emergency involving applications of methyl bromide or chloropicrin, then a self-contained breathing apparatus (SCBA) may be required.

Additionally, EPA now requires that handlers be:

  • fit-tested to ensure respirators will provide the protection they are designed to provide;
  • trained in how to properly use a respirator; and
  • determined to be healthy enough to wear the respirator to ensure they have no problems such as a heart condition that could make use of the respirator dangerous.

Tarp Perforation and Removal: Fumigant gases become trapped under tarps and can be released when the tarp is perforated (i.e., cut, punched, poked) and removed (for application methods in which tarps are removed before planting). Handlers perforating and removing tarps within 14 days of the application may be exposed to air concentrations of concern. To reduce these exposures, we now require the following:

  • a minimum interval of five days between application and tarp perforation;
  • a minimum interval of two hours between perforation and tarp removal; 
  • that handlers stop work or use of respiratory protection if irritation is detected; and
  • use of mechanical devices (e.g., using all-terrain vehicles with cutting implements attached) with few exceptions.

Entry-Restricted Period: Stakeholder comments indicate that reentry for non-handler tasks is generally not needed for several days after the application is complete. EPA is extending the time that agricultural workers (i.e., non-handlers) are prohibited from entering the treated area. The entry-restricted period depends on the method of application, but generally the minimum period for worker reentry will be five days or until after tarps are perforated and/or removed.

Agricultural worker protection fact sheet

Applicator Training Programs and Safety Information for Handlers 

EPA now requires fumigant registrants to develop and implement training programs for applicators in charge of soil fumigation so these applicators are better prepared to effectively manage fumigant operations. The registrants also must prepare and disseminate safety 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 the risks of exposure. The materials must include information on work practices that can reduce exposure to fumigants, and thereby improve safety for workers and bystanders.

Safety information developed by pesticide registrants and approved by EPA

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Good Agricultural Practices 

Older fumigant labels recommended 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 that lead to risks that are 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 

The Agency has determined that all of the soil fumigants undergoing reregistration meet the criteria for restricted use. Therefore, EPA has reclassified metam sodium, metam potassium and dazomet, which had not been restricted, as restricted use pesticides.

Site-Specific Fumigant Management Plans (FMPs)  

Soil fumigation is a complex process that requires specialized equipment and practices to properly apply volatile and toxic pesticides. EPA's risk mitigation allows for site-specific decisions to address the conditions where the fumigant is applied. To address this complexity and flexibility, EPA now requires that fumigant users have a written, site-specific fumigant management plan (FMP) before fumigation begins. 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.

Fumigators capture in the FMP how they are complying with label requirements. FMPs 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.

The certified applicator supervising the fumigation must verify in writing that the FMP is current and accurate before beginning the fumigation. A post-application summary describing any deviations that may have occurred from the FMP must be completed 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-application summary for two years and make them available upon request to federal, state, tribal, and local enforcement officials.

Fumigant management plan fact sheet

Fumigant management plan templates

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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.

First Responder Education: EPA now requires registrants to provide information to first responders in high fumigant use areas. This will help to ensure that emergency responders are prepared to effectively identify and respond to fumigant exposure incidents.

Site-Specific Response and Management Activities: EPA now requires site-specific measures in areas where bystanders may be close to fumigant buffer zones. Fumigators may choose either to monitor the buffer perimeter or to provide emergency response information directly to neighbors. If site-specific measures are required, and the fumigator chooses to monitor, the emergency response plan stated in the Fumigant Management Plan must be implemented if the persons monitoring detect fumigants moving outside the buffer zone toward places where people are. This monitoring must be done during the full buffer zone time period at times when the greatest potential exists for fumigants to move off-site.

If the fumigator chooses instead to provide emergency response information directly to neighbors, the certified applicator supervising the fumigation must ensure that nearby residents and business owners/operators have been provided the response information at least one week prior to fumigant application. The method for distributing information to neighbors must be described in the Fumigant Management Plan.

Emergency preparedness and response requirements fact sheet

Compliance Assistance and Assurance Measures 

Ensuring compliance with new label requirements is an important part of the package of mitigation measures. Some but not all states have mechanisms in place to obtain information needed to assist and ensure compliance with new fumigant requirements. Therefore, in states that wish to receive more information, fumigators must notify State and Tribal Lead Agencies for pesticide enforcement about applications they plan to conduct. This information will aid those states in planning compliance assurance activities.

Community Outreach and Education Programs 

EPA now requires fumigant registrants to develop and implement community outreach programs to ensure that information about fumigants and safety is available in communities where soil fumigation occurs. Outreach programs will address the risk of bystander exposure by educating community members about fumigants, buffer zones, and how to respond appropriately in case of an incident.

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Schedule for Implementing Safety Measures

To achieve new protections, soil fumigant product labels now include new safety measures to reduce risks for the following pesticides:

  • Chloropicrin.
  • Dazomet.
  • Metam sodium.
  • Metam potassium.
  • Methyl bromide.

These changes were implemented in two phases. The phase 1 measures appeared on product labels in late December 2010. Phase 2 safety measures, including buffer zones, are included on fumigant labels approved by EPA in late 2011. (See the Implementation Schedule Fact Sheet for more information.)

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