David J.X. Gonzalez , Rachel Morello-Frosch, Zehua Liu, Mary D. Willis, Yan Feng, Lisa M. McKenzie, Benjamin B. Steiger, Jiali Wang, Nicole C. Deziel, Joan A. Casey

The recent increases in wildfire activity in the western United States has coincided with the proliferation of oil and gas development and substantial population growth in the wildland-urban interface. Drilling and operating oil and gas wells is already associated with emissions of harmful pollutants and higher risks of adverse health outcomes for nearby residents. Perturbation from climate-driven disasters such as wildfire could exacerbate these risks and introduce new hazards. Here, we examined historical threats of wildfires for oil and gas wells, the extent to which wildfires are projected to threaten wells as climate change progresses, and exposure of human populations to these wells. Between 1984 and 2019, we found that 102,882 oil and gas wells were located in wildfire burn areas and cumulatively 348,853 people were exposed (resided ≤ 1 km from these wells). During this period, we observed a five-fold increase in the number of wells in wildfire burn areas and a doubling of the population exposed. Approximately 2.9 million people currently reside within 1 km of the 118,409 wells in high wildfire risk areas, with disproportionately high exposure for communities of color. These trends are projected to worsen, with 87,261 additional wells projected to be in high wildfire risk areas by late century. Policymakers have an opportunity to proactively address expected wildfire impacts on oil and gas development and nearby communities by prioritizing wildfire-threatened wells for retirement, monitoring wells for leaks of flammable gases, and restricting drilling in areas projected to have high future wildfire risk.