EPA’s assessment confirms safety of current uses of pyrethrins and pyrethoid insecticides

Date:11-14-2011

EPA's recently completed cumulative risk assessment indicates that exposures from the many current uses of pyrethrins and pyrethoid insecticides do not pose risk concerns for children or adults. Further, the cumulative assessment supports consideration of registering additional new uses of these pesticides. EPA therefore is issuing this final pyrethins/pyrethroid cumulative risk assessment and requesting comment, including information that may be used to further refine the assessment. Once the agency completes and approves pyrethroid single chemical assessments, it is likely that new uses of these pesticides will be added, providing tools that may alleviate challenging new pest management situations such as the invasive stink bug and bed bugs.

The use of pyrethrins and the pyrethroids has increased during the past decade with the declining use of organophosphate pesticides, which are more acutely toxic to people and wildlife than the pyrethroids. In 2009, EPA identified the pyrethroid chemicals as having a common mechanism of toxicity and has now completed a human health cumulative risk assessment for all uses of the pyrethrins and pyrethroids.

EPA's screening level cumulative assessment considers all registered uses of pyrethrins and pyrethroids and includes exposure from food, drinking water and residential settings through oral, dermal and inhalation routes of exposure. The agency considers this cumulative risk assessment to be highly conservative because it assumes that people are going to be exposed to the highest levels of residues in food, water, and in their homes all on the same day. For example, in estimating residential exposure the assessment assumed no dissipation of the chemicals, all individuals were exposed on the day of application, and exposure for each scenario occurred as a result of the pyrethroid with the highest risk estimate registered for that scenario. The assessment also assumed co-occurrence of certain residential scenarios as worst-case situations. Even using these very conservative assumptions that likely overestimate exposure to pyrethrins and pyrethroids, estimated risks to both adults and children are well below the agency’s level of concern.