Fumigant Phase Out In Vegetables

For many years, soil fumigants have been an essential part of producing vegetables, particularly with plastic mulch. The phase out of methyl bromide has tightened the supply of that universal soil fumigant and caused its price to rise dramatically. Now, many other fumigants, including those that are potential replacements for methyl bromide, may be threatened if regulations proposed by EPA are enacted.

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EPA’s proposed fumigant reregistration eligibility decision (RED) has the potential to make the use of soil fumigants in vegetable production more costly, more restrictive and, in some cases, impossible. The measures that EPA has proposed are aimed at mitigating risk of inhalation exposure from soil fumigant applications.

Among the fumigants affected by this process are chloropicrin, metam sodium, metam potassium, methyl isothiocyanate (MITC), dazomet, and methyl bromide. The newly registered fumigant iodomethane (Midas, Arysta LifeScience) will also be reexamined later this year.

While EPA’s decision on enactment of these new regulations is final, stakeholders will have until Oct. 30, 2008 to comment on implementation of the measures. After receiving comments, EPA can refine implementation of these measures. The new labels are expected to be in effect beginning in 2010. Complete information on these proposed measures can be found at www.epa.gov/opp00001/reregistration/soil_fumigants/#buffer.

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These new rules will cover many aspects of soil fumigant use. Buffer zones are one of the most critical issues affected by the RED. However, posting requirements, agricultural worker protections, applicator handling and training programs, application method and rate restriction, site specific fumigant management plans, and community outreach and education programs are all addressed in the regulations.

The buffer zone requirements alone may take many acres of land currently used for vegetables out of production. The size of the zone, or distance from bystanders, is based on the field size, application rate, application method, and use of emission control measures, such as tarpaulins.

Based on the current proposal, if a grower were to apply chlorpicrin at 70 pounds per acre broadcast equivalent rate in a tarped and bedded field of 50 acres, the buffer zone would be 150 feet. Only trained, equipped, and authorized handlers would be allowed in the area for 48 hours after application. Buffer zones may not overlap and there can be no access to storage buildings, barns, garages, etc. during the buffer zone period. Under the new guidelines, the buffer zones will have to be posted at usual points of entry or likely approach routes to the zone.

Proposed Prohibition

Among the agricultural worker protection requirements proposed will be a prohibition on re-entry of fumigated areas by non-handlers for five days, in general. Also, there will be a five-day required interval between application and tarp perforation and 24 hours between perforation and tarp removal. Additionally, handlers must be fit-tested to ensure respirators fit properly, trained in how to use a respirator, and determined to be physically fit to wear a respirator.

Certain fumigant application practices will also be restricted including some untarped applications. Maximum application rates will also be lowered in most instances. Metam sodium, metam potassium, and dazomet will become restricted use pesticides under the new guidelines.

EPA is also requiring that fumigant users prepare a written, site-specific fumigant management plan (FMP) before fumigations begin. A host of information including site information, applicator information, application procedures, posting, how buffers were determined, emergency plans, and measure for controlling fumigant release must be included in the plan.

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 be required within 30 days of the end of the application. The applicator and grower must keep a signed copy of the FMP and post-application summary for two years.

As part of emergency preparedness, EPA is requiring registrants to provide, through their community outreach programs, training and information to first responders in high fumigant use areas and areas with significant interface between communities and fumigated fields. Applicators must also provide on-site monitoring of buffer zone perimeters for 48 hours in areas where residences occur; or the applicator may provide emergency response information directly to neighbors within the warning zone, at least 48 hours but not more than two weeks prior to application.

While these measures are intended to further protect workers and bystanders from risks due to inhalation of soil fumigants, they will also incur additional costs to an already high input industry. Under the current rules, the risk level for exposure to these fumigants is already quite low.

Certainly, protection from exposure is of paramount importance. However, the impact on the cost and availability of domestically produced fresh vegetables must be considered.

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