Cancer Risk and Diesel Exhaust Exposure Among Railroad Workers

Abstract

Inhalation exposure to diesel exhaust in the railroad work environment causes significant and quantifiable cancer risks to many railroad workers. Diesel exhaust has been identified as a known human carcinogen by the International Agency for Research on Cancer (“IARC”) and as a potential carcinogen by the United States Environmental Protection Agency (“USEPA”), the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (“OEHHA”), and the National Institute for Occupational Safety & Health (“NIOSH”). Peer-reviewed literature defines the ambient air concentrations of diesel exhaust for several railroad occupations as being above environmental background levels. This study uses diesel exhaust concentrations in the railroad work environment in conjunction with the USEPA’s Integrated Risk Information System (“IRIS”) risk assessment methodology to quantify the cancer risk posed to railroad workers due to occupational inhalation exposure to diesel exhaust. NIOSH Bulletin 68 (2017) states that there is “no known safe level” of exposure to carcinogens and recommends an evaluation of the USEPA’s IRIS guidance to evaluate quantitative risk assessment of human exposure to occupational carcinogens. This is the first study to utilize USEPA methodology to calculate the excess lung cancer risk caused by railroad workers’ cumulative exposure to diesel exhaust.