I am an epidemiologist and professor at the George Washington University School of Public Health. My primary expertise is in worker safety and health, and have held Senate-confirmed public health positions in the administrations of President Barack Obama (in which I was Assistant Secretary of Labor for Occupational Safety and Health) and President Bill Clinton (Assistant Secretary of Energy for Environment, Safety and Health). Since the COVID-19 pandemic began, I have worked to improve the protection of workers exposed to SARS-CoV-2. My research has also focused on the integrity of the science underpinning public health and environmental protections. On this topic, I wrote “The Triumph of Doubt: Dark Money and the Science of Deception" (Oxford University Press, 2020) and "Doubt is Their Product" (Oxford University Press, 2008).