Assessing the potential link between chemical exposures from unconventional oil and gas development and risk of childhood leukemia

Abstract

Introduction: Knowledge of health risks of unconventional oil and gas development is sparse, though epidemiologic studies are emerging. Childhood leukemia can be an important outcome to study, as it may be an early indicator of environmental hazards due to the short disease latency and vulnerable exposed population. The objective of this analysis was to evaluate evidence for potential carcinogenic and leukemogenic chemical contaminants in air and water associated with unconventional oil and gas development to inform exposure and health studies. Methods: We obtained a list of 1178 chemicals detected in hydraulic fracturing fluids and wastewater from the US Environmental Protection Agency and constructed a list of 135 air pollutants potentially associated with unconventional oil and gas development based on a comprehensive literature review. We systematically assessed the carcinogenicity and leukemogenicity of these chemicals by searching International Agency for Research on Cancer (IARC) monographs and evaluating whether the monographs cited findings related to leukemia and/or lymphoma. Results: Most chemicals were not evaluated by IARC (91% and 79% of potential water and air pollutants, respectively). Of the 119 unique compounds evaluated (111 and 29 potential water and air pollutants, respectively), 55 (49 and 21 potential water and air pollutants, respectively) were known, probable, or possible human carcinogens. Of these 55 compounds, 21 (17 and 7 potential water and air pollutants, respectively) were associated with increased risk of leukemia and/or lymphoma. Examples include 1,3-butadiene, benzene, cadmium, diesel exhaust, and polycyclic aromatic hydrocarbons. Conclusions: Our assessment underscores the need for air, water, and/or biological monitoring in communities near oil and gas activity and provides support for the investigation of possible associations between unconventional oil and gas development and risk of cancer, particularly leukemia/lymphoma.