Exposure and Risk Considerations for Methyl Salicylate for use on Pre-flowering Bell Peppers and Tomatoes
                    Docket ID Number: EPA-HQ-OPP-2014-0898
                            Date: September 3, 2015
   
ACTION REQUESTED
   
Valent Biosciences Corp. has submitted a request for registration for VBC-60347 Biological Insecticide Emulsifiable Suspension, an end-use product (EP), which contains methyl salicylate and Bacillus thuringiensis subsp kurstaki strain ABTS-351 as its active ingredients. The product is intended for use as a foliar application to tomatoes and bell peppers up to the flowering stage of growth. This new use represents the first use of methyl salicylate as delivered in a manner where it is not enclosed in materials. Methyl salicylate has been previously characterized in the Reregistration Eligibility Decision (RED) Document for Methyl Salicylate, November 2005, available at: http://www.epa.gov/pesticides/reregistration/REDs/methyl_salicylate_red.pdf  This document supersedes the RED with regards to the exposure and risk assessment of methyl salicylate. 

BACKGROUND AND USE PROFILE

Methyl salicylate was first registered in 1972 for use as an animal repellant in impregnated twist tabs to be hung on plants to repel dogs and cats from flower gardens. A subsequent registration of methyl salicylate followed in 1996 as an insect repellent to be used as a constituent of food and feed packaging material to repel insects in stored commodities. This registration was considered to be a "food use," and thus necessitated the establishment of an exemption from the requirement of a tolerance (see 40 CFR §180.1189).  

The proposed new registration, VBC-60347 Biological Insecticide Emulsifiable Suspension, is a highly selective insecticide for use against listed caterpillars (larvae) of Lepidopterous insects. It is formulated as an emulsifiable suspension which contains 5.95% of the active ingredient (a.i.) methyl salicylate (CAS Number 119-36-8). VBC-60347 is applied as foliar spray using ground or handheld equipment to bell peppers and tomatoes in fields and or greenhouses at an application rate of 1.0 to 4.0 pints/acre, up to a total of 16 pints per acre per season. Applications are to be applied up to the flowering stage of growth and must not be applied more frequently than every 5 days. 

The personal protective equipment statement on the VBC-60347 Biological Insecticide Emulsifiable Suspension proposed product label indicates that all applicators and other handlers must wear a long sleeved shirt and long pants, chemical resistant gloves, socks and shoes. Mixer/loaders and applicators must wear a dust/mist filtering respirator meeting NIOSH standards of at least N-95, R-95, or P-95. Repeated exposure to high concentrations of microbial proteins from the second active ingredient, Bacillus thuringiensis, subsp. kurstaki, strain ABTS-351, listed on the proposed label can cause an allergic sensitization.

EXPOSURE AND RISK ASSESSMENT

Dietary Exposure and Risk

The proposed new use of methyl salicylate as a foliar spray on field and greenhouse pre-flowering tomatoes and peppers is considered a non-food use since the residue data indicate that methyl salicylate will not be present on the crop at the time of harvest. Methyl salicylate has a half-life of less than two and a half hours on foliage. It is readily biodegradable in screening tests and may be expected to biodegrade in soils and surface waters (U.S. EPA, 2005). Moreover, methyl salicylate is likely to hydrolyze in water, especially at alkaline pH (U.S. EPA, 2005).  Therefore, the potential for dietary exposure is negligible and there are no risks of concern associated with the proposed use.  

Residential Exposure and Risk

The proposed new use as a foliar application to field and greenhouse pre-flowering tomatoes and bell peppers is not intended for use in residential settings.  However, methyl salicylate is registered for use in residential gardens as a repellent to dogs and cats. The registered residential product is formulated as ready to use, self-contained impregnated twist tabs which are hung in home gardens thereby significantly limiting the potential for dermal and inhalation exposure.   

The potential for post-application dermal and inhalation exposure resulting from entry into treated areas is also anticipated to be negligible. Vapors released from the plastic matrices twist ties are released in small amounts over an extended period of time.  Therefore, it is very highly likely that any trace of the active ingredient will have completely dissipated. Although there is potential for incidental non-dietary exposure to young children, the likelihood of an incident is anticipated to be very low. The extent to which young children will be engaged with the end-use product in home gardens for prolonged periods of time is low and significant non dietary ingestion exposure is not expected.    

Aggregate Exposure and Risk

In accordance with the Food Quality Protection Act (FQPA), the Agency must consider and aggregate pesticide exposures and risks from three major sources; food, drinking water and residential exposures. Methyl salicylate is currently registered as an insect repellent in food packaging. An exemption from the requirements of a tolerance for residues of the insecticide Methyl salicylate in or on food, when used as an insect repellent in food packaging and animal feed packaging at an application rate that does not exceed 0.2 mg of methyl salicylate per square inch of packing material was established at 40 CFR §180.1189. To mitigate and offset potential exposure to workers handling this manufacturing use product, explicit product labeling statements requiring personal protective equipment (e.g., rubber gloves, splash-proof goggles, and/or full face shield) are required.

The proposed new use of methyl salicylate as a foliar spray on field and greenhouse pre-flowering tomatoes and peppers is considered a non-food use since the residue data indicate that methyl salicylate will not be present on the crop at the time of harvest. It is readily biodegradable in screening tests and may be expected to biodegrade in soils and surface waters (U.S. EPA, 2005).  Therefore, the potential for dietary exposure is negligible and there are no risks of concern associated with the proposed use.  

There are two registered pesticidal uses for methyl salicylate as cat and dog repellents on ornamental shrubs and bushes. Since the end use product is formulated as ready to use, self-contained impregnated twist tabs which are hung in home gardens thereby significantly limiting the potential for applicator dermal and inhalation exposure. The potential for post-application dermal and inhalation exposure resulting from entry into treated areas is also anticipated to be negligible.

The exposure to humans from the pesticidal use of methyl salicylate is expected to be minimal, compared with the widespread use of methyl salicylate as a flavoring ingredient in foods. Based on these considerations and those listed in the previously described hazard assessments, an assessment of an aggregate exposure for all pesticidal uses of methyl salicylate would result in minimal additional exposure;  expected exposure levels from these uses would be well below defined acceptable levels, even considering the sensitivity of infants and children. 

Occupational Exposure and Risk

VBC-60347 is applied as foliar spray using ground or handheld equipment to pre-flowering bell peppers and tomatoes in fields and or greenhouses at an application rate of 1.0 to 4.0 pints/acre.  Applications are to be made up to the flowering stage of growth. There is potential for dermal and inhalation exposure to occupational handlers, specifically females of child bearing age, while mixing/loading and applying the proposed product.  However, the low level of potential exposures (dermal and inhalation) during the mixing/loading and application process of this biochemical are more than adequately mitigated by the use of personal protective equipment and  precautionary language statements placed on end-use product labels. In addition, any potential inhalation exposure from methyl salicylate are deemed to be minimal because inhalation exposures will be less than those conducted in a saturated (more concentrated) atmosphere which had no indication of toxic effect in laboratory animals.

Furthermore, since methyl salicylate has a half-life of less than two and a half hours on foliage and is readily biodegradable and may be expected to biodegrade in soils, the potential for post-application dermal and inhalation exposure is anticipated to be negligible and risk of concern to workers entering treated areas.

Cumulative Effects

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as to methyl salicylate and any other substances and methyl salicylate does not appear to produce a toxic metabolite produced by other substances. For the purposes of this action, therefore, EPA has not assumed that methyl salicylate has a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements released by EPA's Office of Pesticide Programs concerning common mechanism determinations and procedures for cumulating effects from substances found to have a common mechanism on EPA's website at: http://www.epa.gov/pesticides/cumulative/.

REFERENCES CITED

U.S. EPA, 2005. Reregistration Eligibility Decision (RED) Document for Methyl Salicylate, United States Environmental Protection Agency (U.S. EPA). November, 2005. Available at: http://www.epa.gov/pesticides/reregistration/REDs/methyl_salicylate_red.pdf

U.S. EPA, 2006. Inert Reassessments: One Exemption from the Requirement of a Tolerance for Wintergreen oil (CAS Reg. No. 119-36-8). Memorandum from Pauline Wagner to Lois A. Rossi. United States Environmental Protection Agency (U.S. EPA). June 8, 2006. Available at: http://www.epa.gov/opprd001/inerts/wintergreen.pdf 
