Big Win for Children's Health in Second Circuit Risk Assessment Decision

In toxics regulation, environmental lawyers face an uphill battle when they challenge a risk assessment performed by a protector agency.  Courts review the agency’s risk assessment under a deferential “arbitrary and capricious” standard, and courts are reluctant to second-guess an agency’s calculation of the risks of a pesticide or other chemicals.

So it was a victory for both children’s health and sound science earlier this month when the Natural Resources Defense Council prevailed in its challenge of EPA’s flawed risk assessment for a commonly-used pesticide called dichlorvos. (NRDC v. EPA, 08-3771-ag, 2^nd Cir. September 16, 2011).  The unanimous decision by the 3-judge panel is here.

The Second Circuit vacated a 2006 EPA order denying NRDC’s request to pull dichlorvos off the market.  The court held that EPA acted arbitrarily and capriciously in denying the request and that EPA had failed to carry out Congress’s clear mandate, in the 1996 Food Quality Protection Act (FQPA), to protect children’s health.  Now EPA must reconsider NRDC’s petition using better science and the correct statutory standard. 

Dichlorvos is an organophosphate pesticide that has been in use since 1948 in homes, restaurants, and commercial buildings.  It is a vapor-based pesticide, commonly used in pet collars and also sold on strips to attract aphids, mites, and other insects.  Vapor-based pesticides pose particular risks to children through inhalation exposure.  In the 1980s, EPA had considered pulling dichlorvos off the market because there was evidence that it was a carcinogen, but in 2000, the agency approved continued use.  That decision was based primarily on a single study involving only nine adult volunteers – and the study was paid for by the pesticide’s manufacturer.

In addition to the ridiculously small sample size, another problem with EPA’s risk assessment from a decade ago was that EPA never applied the 10-fold safety factor that Congress mandated in the FQPA for setting maximum pesticide “tolerances.”  Concerned about the special vulnerability of children to pesticide exposure, Congress had mandated that EPA implement this 10-fold safety factor “to take into account potential pre-and post-natal toxicity and completeness of data with respect to exposure and toxicity to infants and children.” 

In an opinion by Judge Rosemary Pooler, the Second Circuit found that EPA had ignored the 10-fold safety factor in relying on the study with adult volunteers, and therefore the allowable exposure levels were set too high.  The court also concluded that EPA had never provided an adequate reason for failing to implement the Congressional mandate.  EPA now must go back to the drawing board to assess the risks of dichlorvos again, and if it implements the 10-fold safety factor, the allowable uses of the pesticide could be substantially reduced.  EPA may also decide the pesticide poses unreasonable risk and pull it off the market.

This case is a big win for the public health, and it stands out because the court looked behind agency assurances of safety to engage in a close examination of the science (the scientific discussion spanned about 15 pages in the opinion).  This close scrutiny of agency safety claims is unusual in toxics regulation, and we should welcome courts holding EPA to its statutory mandates.  Most people don’t realize that when EPA regulates pesticides and chemicals, it relies overwhelmingly on manufacturer-supplied data.  The opportunities for bias and skewing results are obvious.   If we’re going to rely on this system (and there’s little choice under current statutes), both the EPA and the courts need to remain skeptical of manufacturer claims of safety.