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Proposed Registration of the New Active Ingredient Momfluorothrin

Proposed Regulatory Action: 

EPA is proposing to grant an unconditional registration for the new active ingredient, 

momfluorothrin, formulated as four manufacturing-use products and five end-use products. I2L 

Research USA Inc., on behalf of Sumitomo Chemical Company, and McLaughlin Gormley King 

Company requested this action. Momfluorothrin belongs to the synthetic pyrethroid class of 

chemicals and is a broad spectrum insecticide effective against flying, crawling, and stinging 

insects and other arthropod pests. The proposed uses for this new chemical include indoor and 

outdoor spot and crack-and-crevice treatments in residential and commercial settings, including 

application to indoor perimeters and mattresses to control bed bugs. The five end-use products 

are formulated, in combination with previously registered active ingredients, as ready-to-use 

aerosols.

Human Health Risk Assessment: 

The database submitted to support the assessment of human health risk is complete. The 

proposed uses are non-food uses and adequate exposure data are available to assess potential 

residential and occupational exposure. The Agency is adding a 3X safety factor based on 

pharmacokinetic considerations (consistent with other pyrethroids) for infants and children <6 

years old. EPA has determined that the proposed residential uses of momfluorothrin will not 

contribute significantly to or change the overall findings of the 2011 pyrethroids/pyrethrins 

cumulative risk assessment. There are no risk estimates of concern for human health. Estimates 

of both residential and occupational handler and post-application risk are well below EPA’s level 

of concern. Furthermore, as the proposed uses are non-food uses, limited in scope, there will be 

no exposure to momfluorothrin through food or drinking water.

Ecological Risk Assessment: 

Results from a screening-level ecological risk assessment indicate low potential for risks to nontarget organisms. The environmental fate and ecotoxicity databases are sufficient for assessing 

the risks associated with the proposed uses. Momfluorothrin is considered practically non-toxic 

to birds and mammals. Although momfluorothrin is classified as highly toxic to fish, aquatic 

invertebrates, and terrestrial invertebrates, predicted exposures from ready-to-use aerosol 

formulations are expected to be spatially restricted to small areas. Thus, risk of adverse effects is 

considered low. 

Endangered Species: 

The proposed uses of momfluorothrin are unlikely to result in direct or indirect adverse effects to 

listed species of any taxon. Thus, a “no effect” determination is made. 

Efficacy/Benefits: 

Momfluorothrin is efficacious against several pests of public health concern, including flies, 

mosquitoes, wasps, hornets, yellow jackets, roaches, ticks, bed bugs, scorpions, centipedes, and 

certain species of ants and spiders. Additionally, momfluorothrin has a lower ecological hazard 

profile relative to alternative registered products across several taxa.
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Data Requirements: 

There are no outstanding data requirements at this time for momfluorothrin. Outdoor use 

expansions including broadcast applications would trigger additional data requirements.

Mitigation and Labeling Requirements: 

To mitigate potential exposure to smaller water bodies in close proximity to treated areas, 

outdoor applications are limited to spot and crack-and-crevice treatments, and product labels 

prohibit application within 25 feet of water. To reduce risk to insect pollinators, application is 

prohibited if bees are foraging in treatment areas.