The Effects of Arsenic Standards on Birth Outcomes in California by Dr. Gabe Lara – Natural Resource Economist – Hazen and Sawyer

Abstract

Despite Safe Drinking Water Act protections, many communities remain exposed to regulated contaminants, raising concerns about enforcement and equity. This paper estimates the causal effect of arsenic exposure from drinking water violations on birth outcomes, exploiting geological variation in groundwater arsenic concentrations across California. We find that pregnancy-averaged MCL exceedances increase preterm birth and low birth weight in very small systems. Results demonstrate regulatory effectiveness depends critically on system resources, with health burdens concentrated in resource-constrained settings.