In mid-April, a Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) was convened to review: “Chlorpyrifos: Analysis of Biomonitoring Data.” During the meeting of the SAP, members listened to comments from a diverse audience specifically regarding the use of a Columbia University epidemiology study (Columbia Study) for human health risk assessment. Consistent with two previous SAPs held in 2008 and 2012, SAP members again questioned the usefulness of the outcomes from this specific epidemiological study. The final transcript from the SAP is now available online.

Last year, following a petition seeking the revocation of chlorpyrifos, the U.S. 9th Circuit Court of Appeals denied a request from the U.S. Environmental Protection Agency (EPA) to extend its deadline to make a revocation decision to April 15, 2016. The court instead ordered the Agency to respond by October 31, 2015, before EPA had an opportunity to complete portions of its chlorpyrifos risk assessment.

During the April SAP, public speakers presented the SAP with a number of limitations of the Columbia Study, including lack of access to raw data; exposure measures used; small population reported in the study; and the inability of EPA or others to replicate the study outcomes. The SAP’s official recommendations, due in mid-July, could potentially impact EPA’s stated intention, largely based on the Columbia Study outcomes, to revoke all chlorpyrifos tolerances by December 2016.

“We were pleased that the panelists in April recognized the limitations of this epidemiological data in human health risk assessment,” stated Jay Vroom, CEO and president of CLA. “Yet again, SAP panel members have recognized the importance of reliability in data. It’s now EPA’s responsibility to heed the panel’s recommendations and keep our food production standards high. We call on EPA to base its regulatory decisions on hard toxicological data and continue to get the most advanced and the most sustainable crop protection products to farmers.”

Questions from the panelists highlighted confusion about the Columbia Study, discomfort with the potential regulatory use of the study, and the need for confirmatory studies prior to any serious considerations of the reported associations from epidemiological studies and any potential relationship to human health impacts in children. A key deficiency of the Columbia Study is that the data are not available for EPA to review and are not verifiable; in addition, the outcomes are limited in time to one biological blood sample without connection to a timeframe for exposure to the pesticide.

Key points raised by experts at the SAP, according to the transcript, include:

  • “Maybe the data doesn’t need to be quite that rigorous but it needs to have rigor in order to put the EPA in a position of defending their decisions,”[1] Dr. Marion Ehrich from Virginia Tech stated in her presentation. “You certainly have to have enough data, enough strong data, in order to think about a cancellation. So if we’re basing this on one study where it’s not been reproduced, you can’t get the actual hard data, there’s lots and lots of points below levels of detection, one has to give that really serious thought.”
  • Dr. Panos Georgopoulous from Rutgers Biomedical and Health Sciences noted in his presentation that the court-imposed legal timeframe for human health risk assessments “presents challenges that are insurmountable.”[2] He added that “lower [reference doses] would be safer but it is supposed to be bounded within the realm of what is believed to be within an order of magnitude of risk.”[3] Dr. Georgopoulous further stated, “Having seen [kinetic modelling] and having learned the things that it does in terms of fast rates of metabolism, it just led me to really reject that cord data [from the Columbia Study]. I just can’t say it strongly enough.”[4]

“The EPA’s risk-based approach to crop protection regulation historically has centered on use of relevant, reliable and best available scientific data,” stated Dr. Janet E. Collins, senior vice president of science and regulatory affairs at CLA. “Regulatory decisions based on studies that are not yet validated and have many factors lacking adequate scientific control is not responsible. The panelists in April’s SAP underscored they are reviewing the same information that two others SAPs reviewed in 2008 and 2012 and that the long-agreed point of departure for risk management still holds. While our members are pleased with the SAP questions and comments, we urge EPA to stay its prior course in maintaining a priority on solid scientific evidence.”

[1] U.S. Environmental Protection Agency, FIFRA Scientific Advisory Panel. Meeting on Chlorpyrifos: Analysis of Biomonitoring Data. Page 766.

[2] Ibid, page 780.

[3] Ibid, page 747.

[4] Ibid, page 775.