Based on a thorough review of recent data, the U.S. EPA concluded that there are reliable data to support reducing the current threefold (3X) Food Quality Protection Act (FQPA) safety factor for pyrethroids to 1X, and that margin will be safe for infants and children. This reduced safety factor will be incorporated into the upcoming pyrethroid proposed interim decisions for registration review.

EPA is required to apply a 10X margin of safety, or safety factor, to human health risk assessments to account for potential prenatal and postnatal toxicity of infants, children and pregnant women when exposed to pesticides. The law allows a different margin of safety only if the Agency has reliable data supporting a conclusion that the revised safety factor would protect infants and children.

The Agency considers the FQPA safety factor to have two components: one assigned to pharmacokinetic (PK) differences and another for pharmacodynamic (PD) differences. The PK component refers to the process of chemicals being absorbed, distributed, metabolized and excreted from and in the body. The PD component refers to how a chemical affects the body’s tissue.

In 2010, EPA reviewed the data relevant to assessing the health risks of pyrethroid exposure to infants and children and found that they supported the removal of the safety factor for PD. However, the data were insufficient to change the PK portion of the uncertainty factor, thus leaving a 3X safety factor.

More recently, EPA has performed a new evaluation of available guideline and literature studies, as well as data generated by the Council for the Advancement of Pyrethroid Human Risk Assessment. The Agency concluded that the FQPA safety factor for pyrethroids should be reduced to 1X for all populations (1X for PD and 1X for PK) because the data indicate that there is no increased sensitivity, or in other words, there are no PK differences between adults and children.

Pyrethrins and pyrethroids are insecticides widely used in and around households, including on pets. They are also used in treated clothing, mosquito control, and agriculture.

Source: Agropages