The Big Drop · Infrastructure Investigation
The Big Boom
Buried under thousands of American neighborhoods runs a high-pressure gas line with a blast radius. The Blast-zone Explorer shows who lives inside it — and why no one has to tell them.
Open the catalog →Find a school or hospital in the blast zone
Every marker is a real school or hospital that sits inside a transmission line's blast radius. Click one to see what a rupture at the nearest line would reach — and why, and adjust the pipe size to watch the radius grow.
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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.
What a blast radius means
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.
Defined at 49 CFR §192.903 — the federal standard for a pipeline's High Consequence Area.
A controller can't choose where a line bursts
The pressure inside these lines is managed by supervisory control and data acquisition (SCADA) systems — the industrial controls that run 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.
How the numbers were calculated, and why there’s no exact count.
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:
- Pipelines — EIA National Gas Interstate & Intrastate transmission centerlines (32,961 operating segments).
- Schools — NCES geocoded public and private schools (124,778 total).
- Hospitals — CMS Hospital General Information, geocoded through the U.S. Census batch geocoder (4,630 located).
- Blast ring — a representative PIR (1,100 ft large main, 660 ft typical), since a line's true PIR depends on its diameter and pressure.
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.
Sources — Pipeline geometry: U.S. EIA Natural Gas Pipelines · full inventory (viewer): PHMSA National Pipeline Mapping System · PIR standard: 49 CFR §192.903 · Schools: NCES EDGE · Hospitals: CMS + U.S. Census geocoder. Retrieved 2026. © 2026 The Big Drop.