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Review of the Relationship between Pyrethrins, Pyrethroid Exposure and Asthma and Allergies

EPA used a weight of evidence approach to determine whether an association exists between pyrethrins/pyrethroid exposure and asthma and allergies. The current review included data from both animals and humans. The Agency considered animal data regarding mode of action; target organ of toxicity; acute inhalation and dermal irritation; and sensitization. The Agency also considered human data including incident data from several sources and epidemiology studies.

Based on the current analyses, the Agency concluded there is no clear and consistent pattern of effects reported to indicate conclusively whether there is an association between pyrethrins/pyrethroid exposure and asthma and allergies. The Agency is not requiring additional warnings or label statements specific to asthmatic or allergic individuals on pyrethroids and pyrethrins end-use products, nor is the Agency requiring additional data from pyrethroid registrants at this time. However, in order to clarify the issue of possible correlation between use and incidents, the pyrethrins registrants have committed to a product stewardship program that will include a prospective in-depth follow-up of reported pyrethrins incident cases. The Agency will review the pyrethrins incident data as it is submitted. If the Agency identifies discrepancies or trends in the in the data that differ from the incident data considered in this review, the Agency will consider requiring additional or similar data from the pyrethroid registrants.

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