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.