Unconventional Natural Gas Development and Infant Health: Evidence from Pennsylvania

摘要

Background: Due to increased natural gas wellhead prices, hydraulic fracturing has become a prevalent method for extracting natural gas from shale formations around the United States. Over the last decade, 31 states have begun using this technology. There are numerous environmental and health concerns related to this technology, but to date, there is no study that has been able to link hydraulic fracturing with human health. Aims: This research exploits the introduction of hydraulic fracturing in natural gas wells to identify the impacts of potential air pollution and water pollution on infant health. Infants do not have a lifetime of exposure to toxic chemicals to control for and so we focus on infant health measures as our outcomes of interest (low birth weight, prematurity, birth weight, gestation and APGAR scores). Methods: Using detailed vital statistics, exposure is defined by close proximity to a well head prior to birth. The difference-in-differences design utilizes the unique retrospective data of drilled wells and permitted wells and compares birth outcomes for mothers who live within 2.5 km of a drilled well to mothers who live within 2.5 km of a future well (permitted). Results: When utilizing a difference-in-differences estimator, the results suggest that infants born to mothers who live within 2.5 km of a drilled well prior to birth weigh less and are more likely to be both low birth weight. Little impact on premature birth or gestation period is detected. Conclusions: Exposure prior to birth to unconventional natural gas development has adverse effects on infant health at birth for mother's residences within 2.5 km of a well head.