Buried under thousands of American neighborhoods runs a high-pressure gas line with a blast radius. This is who lives inside it — and why no one has to tell them.
Counts at a 1,100-ft PIR (a large transmission main). At a smaller 660-ft PIR: 4,111 schools and 152 hospitals. Figures are a floor — see the method.
The engineer's term is the Potential Impact Radius, or PIR: the ring around a buried high-pressure line — roughly 1,100 feet for a large transmission main — inside which a ruptured, ignited line can cause catastrophic destruction. When such a line tears open and ignites, it throws up a column of flame and thermal radiation intense enough to burn through walls, ignite homes, and kill people outright in seconds, before anyone can evacuate.
Every marker below is a real school or hospital that sits inside a transmission line's blast radius. Zoom to your town, click one, and see what a rupture at the nearest line would reach — and why. Adjust the pipe size to see how the blast radius grows.
The pressure inside these lines is managed by SCADA — the industrial control systems that ranch valves and compressors across the network. A compromised controller that overpressures a line can't choose where it fails, yet the people inside the ring get no warning and no say. And almost none of them know they're there: no law requires a pipeline operator to tell a school or a hospital that it sits inside the PIR. Most have never been told they're in danger.
Every figure here is reproducible from public federal data. A facility is counted "in range" if it falls within the PIR buffer of any operating transmission line, measured in an equal-area projection:
Why there is no single exact number: the precise count would require each line's actual PIR — which needs its diameter and maximum operating pressure — but operators do not disclose those per segment, and the full National Pipeline Mapping System geometry is not available for public download. So these are a floor: the public pipeline map is sparser than the complete inventory, and the hospital set counts only Medicare-certified facilities. The real number is higher than what any public dataset can prove — and there is no requirement that anyone find out. The blast-zone explorer models a rupture at a representative pipe size; it is an illustration of scale, not a prediction of any specific line's behavior.