Midstream oil and gas infrastructure comprises vast networks of gathering and transmission pipelines that connect upstream extraction to downstream consumption. In the United States (US), public policies and corporate decisions have prompted a wave of proposals for new gathering and transmission pipelines in recent years, raising the question: Who bears the burdens associated with existing pipeline infrastructure in the US? With this in mind, we examined the density of natural gas gathering and transmission pipelines in the US together with county-level data on social vulnerability. For the 2,261 US counties containing natural gas pipelines, we found a positive correlation between county-level pipeline density and an index of social vulnerability. In general, counties with more socially vulnerable populations have significantly higher pipeline densities than with less socially vulnerable populations. In particular, counties in the top quartile of social vulnerability tend to have pipeline densities that are much higher than pipeline densities for counties in the bottom quartile of social vulnerability. The difference grows larger for counties at the upper extremes of pipeline density within each group. We discuss some of the implications for Indigenous communities and others affected by recent expansions of oil and gas infrastructure. We offer recommendations aimed at improving ways in which decision-makers identify and address the societal impacts and environmental justice implications of midstream pipeline infrastructure.

Midstream oil and gas infrastructure comprises vast networks of gathering and transmission pipelines that connect upstream extraction sites to downstream processors, exporters, and consumers. In the United States (US), public policies and corporate decisions continue to promote the extraction and consumption of oil and gas, and they have prompted a wave of proposals for gathering and transmission pipelines in recent years. The ongoing build-out of midstream infrastructure calls for close scrutiny of associated human health risks and related societal impacts. Urgency is warranted considering that at least part of this infrastructure, the US natural gas pipeline network, is concentrated more heavily in areas of high social vulnerability than areas of low social vulnerability, highlighting inequity in the distribution of societal harms. Emerging research on ways in which midstream pipelines affect Indigenous peoples and rural communities in the US demonstrates the complex nature of potential harms. The spatial distribution of midstream infrastructure, together with the complexity of societal impacts underscore the need to clearly understand and carefully consider these impacts during infrastructure planning and permitting. We offer recommendations for scientists and decision-makers who are interested in evaluating these impacts through the lens of environmental justice.