In an article published on March 19, 2020, Environmental Health News (EHN) reported on the publication of four letters in the April 2020 issue of the medical journal The Lancet about the ongoing scientific debate on human exposure to bisphenol A (BPA; CAS 80-05-7). Following a journal article published in December 2019 arguing that a method used by federal regulators significantly underestimated the concentration of BPA in human blood and urine samples (FPF reported), the four letters from separate groups of international scientists continue the discussion.

The first letter led by a scientist from the U.S. Centers for Disease Control and Prevention (CDC) defended the indirect method used by regulatory agencies in the U.S. arguing that data presented in the December 2019 study “do not support the view that the indirect methods underestimate urinary BPA concentrations and thus BPA exposure.” The second letter from researchers at the University of Aberdeen stresses that “continued use of assays that underestimate just how much BPA is present in the environment are a potential health risk” and they “urge regulators to take note.” In the third letter, scientists at the Université de Poitiers argue in favor of using the direct measurement method for BPA and also share their concern that underestimation may be an issue also for the measurement of many other environmental chemicals.

In the fourth letter, Patricia Hunt and co-authors of the original publication from December 2019 respond to the criticism raised in the first letter and write that “Antonia Calafat and Holger Koch provide no criticism of our methods, findings, or the profound implications for BPA risk assessments.” Instead, they say the authors cannot defend their method due to a lack of standards and ignorance of additional factors that influence the BPA profile in blood and the presence of metabolites in urine. They conclude by saying “our findings demand more than a defense of outdated, inaccurate technology. To echo Palmer and Speirs [the authors of the second letter], we urge regulators to take note and—more importantly—take action to ensure the accuracy of BPA measurements used by epidemiologists and in risk assessments.”

On March 24, 2020, the non-governmental organization the Collaborative on Health and the Environment (CHE) is holding a webinar with Patricia Hunt to discuss her December 2019 publication. Registration for the webinar is open, and it will be recorded and made publicly available afterward.

Read more

EHN (March 19, 2020). “BPA exposure: Scientists spar over how contaminated we really are.”

CHE (March 2020). “Underestimating BPA levels: The need for reanalysis of population data and reassessment of risk is urgent.”


Calafat, A. et al. (April 2020). “BPA and risk assessment.” The Lancet, 8(4)

Palmer, K and Speirs, V. (April 2020). “BPA and risk assessment.” The Lancet, 8(4)

Dupuis, A. et al. (April 2020). “BPA and risk assessment.” The Lancet, 8(4)

Hunt, P. et al. (April 2020). “BPA and risk assessment.” The Lancet, 8(4)