Soil Fumigant Use in Wisconsin

Phase 2 of the U.S. Environmental Protection Agency's (EPA) label changes for soil fumigants is in effect as of December 1, 2012. The Wisconsin Department of Agriculture, Trade is working with the EPA to provide information about these changes.

Soil fumigants are pesticides that form a gas when applied to soil to control nematodes, fungi, bacteria, insects and weeds and other pests. As gases, they move from the soil to the air at the application site and may move off site at concentration that pose health risks to people from hours to days after application.

Because of this risk, the U.S. Environmental Protection Agency is requiring extensive new safety measures to protect agricultural workers and those who live, work or spend time near fumigated fields. Phase 1 of the measures was enacted in 2010. Phase 2 measures began appearing on product labels in December 2012. The new measures apply to products containing: 

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

In addition to these new label requirements, applicators must also adhere to the Worker Protection Standard and, in Wisconsin, to ATCP 30.22, which covers agricultural use of metam sodium and chloropicrin.

Phase 2 Requirements Print-friendly version (4 page PDF)

Wisconsin ATCP 30 (agricultural chloropicrin and metam sodium use)

Phase 2 Requirements

Sales and distribution -- Product registrants can sell or distribute only products bearing approved Phase 2 labels. Distrib­utors and retailers who are not registrants may sell and distribute existing stocks bearing Phase 1 la­bels until their supplies are exhausted. Similarly, growers and applicators may apply products bear­ing Phase 1 labels until those supplies are ex­hausted.
Back to top

Buffer zones -- Every treated area will need a buffer zone from 25 feet to a half mile, to exclude non-handlers for at least 48 hours after treatment.

The size of a buffer zone is specific to each appli­cation and depends on factors such as field size, application rates, methods of application and equipment. Phase 2 labels will carry look­up tables to determine buffer distances.

Applicators can receive “credits” for using prac­tices that reduce emissions such as using high-bar­rier tarps. Applying credits reduces the size of buffer zones.

The smallest buffer zone distance is 25 feet. Also, buffer zone distances cannot be greater than ½ mile (2,640 feet). If after applying applicable cred­its, the buffer zone distances are still greater than ½ mile, the application is prohibited.

In addition to credits, other options to reduce the size of buffer zones are to change the factors that determine the size of the zone. Examples include breaking the treated area into smaller block sizes or using a lower application rate or different active ingredient. Applicators should consider these options prior to the completion of the FMP.

Electronic calculators may assist applicators determine buffer zone distances and credits. Remember that these calcula­tors are only tools and applicators must follow the product label if there is any discrepancy between buffer zone distances using the label compared with using the calculator.

The size of the buffer zone is important for deter­mining whether or how other new label require­ments apply. These requirements are addressed in the Difficult to Evacuate Sites and Emergency Preparedness and Response Measures sections.

Unless certain label requirements are met, buffer zones cannot:

  • Overlap with each other.
  • Include storage buildings under the control of the owner of the application block.
  • Include residential areas, outdoor residential areas, buildings, or other areas that people may occupy.
  • Include agricultural areas owned and/or operated by persons other than the owner of the applica­tion block.
  • Include roadways and rights-of-way.
  • Include other publicly owned and/or operated areas. 

EPA information on buffer zones 

Back to top

Posting requirements for buffer zones – Unless a physical barrier prevents access to the buffer, signs must be posted at points of entry and likely approach routes no sooner than 24 hours before application, must remain posted until the buffer zone period expires, and must be removed within 3 days after application.

The requirements for information on the buffer zone sign, location of posting and duration of posting are different from those for the Fumigant Treated Area sign already required by labels.

EPA information on buffer zone posting
Back to top

Fumigant management plans – In addition to requirements in Phase 1, FMPs will now have to include a map, aerial photo or detailed sketch of the application site; buffer zone and posting information; emergency preparedness and response measures; and other Phase 2 labeling information. Some other details have been revised, omitted or moved to new sections.

EPA information about FMPs 
Back to top

Difficult to evacuate sites – Unless certain label requirements are met, soil fumigant applications will be prohibited within ⅛ mile of sites with a buffer zone of 300 feet or less and within ¼ mile of sites with a buffer zone of more than 300 feet of sites such as schools, day care centers, prisons, and hospitals if they are occupied during the application or in the hours afterward.

Wisconsin's administrative rule ATCP 30 also addresses this issue for agricultural use of chloropicrin and metam sodium. Applicators must take both Phase 2 and ATCP 30 into consideration.

Chart showing which requirements to follow (1 page PDF)
Back to top

Emergency preparedness and response – If the buffer zone is more than 25 feet or if buffer zones overlap, and there are residences or businesses within a certain distance, emergency preparedness and response are triggered. Applicators must do one of the following:

  • Monitor for sensory ir­ritation in areas between the buffer zone outer perimeter and the residences and businesses, or
  • Provide emergency re­sponse information directly to neighbors at least 1 week before the application.

If the meas­ures are triggered, the FMP must include details regarding the selected response option. If the monitoring option is chosen, and someone experiences sensory ir­ritation, the emergency response plan outlined in the FMP must be implemented immediately.

EPA information about emergency preparedness and response
Back to top

Applicator training – Certified applicators who supervise soil fumigant applications will need to complete EPA-approved training programs specific to the active ingredients used.  The FMP must document the date and location where the soil fumigant training program was completed.

Wisconsin applicators can satisfy this requirement by taking and passing the recertification exam now for the soil-fumigant subcategory, even if their certification has not expired. The new requirements have been incorporated into the test.  Note that all applicator certifications expire concurrently. So, applicators may want to take all of their certification exams early and start the 5 year clock ticking again. Otherwise the newly passed soil-fumigant certification will expire when the applicator’s other certification expires – which means it expires sooner than the usual five years.

EPA-approved training programs
Wisconsin Pesticide Applicator Training
Back to top

Notice to state and tribal agencies – The new labels require applicators to provide advance notification of soil fumigations to the state and/or tribal lead agency for the area in which they are making an application, if required by either or both of those agencies. Labels include an address for a website for applicators to check. DATCP is not requiring advance notification of applications. However, applicators still need to determine whether and how the tribes in Wisconsin require notification.

Contact information for tribes

Safety information for communities and first responders -- In addition to these new label provisions in Phase 2, the EPA will require manufacturers (registrants) of these soil fumigant products to provide safety information to communities and first responders in high use areas. EPA has determined that Wiscon­sin is a “high fumigant use” state based on metam sodium use on potatoes. (On average, over a 10-­year period, more than 100,000 pounds of metam sodium have been applied annually.)

EPA information

For more information

For questions about label requirements: Otto Oemig,, 608-224-4547.

For questions about certification and licensing: Mike Murray,, 608-224-4551.