Citizens of the small New Mexico town of Farmington noticed their windows shaking on December 10, 1967. Some probably assumed it was an earthquake, but many had been forewarned. Fifty-five miles away, the Atomic Energy Commission was detonating a nuclear bomb deep underground that was equivalent to 26,000 tons of TNT. The military had been testing bombs in New Mexico’s deserts since World War II and the Manhattan Project, but this detonation was different: It was researching whether atomic blasts could fracture rock formations and free natural gas for extraction.

This half-century-old precursor to fracking may sound outlandish, but the test the AEC called “Gasbuggy” was just one component of Project Plowshare — a 20-year investigation of peaceful uses for the nation’s growing atomic arsenal. Officials believed the biblically named program could help justify massive expenditures on nuclear weapons in the midst of the Cold War by demonstrating that they had some value beyond simply leveling the Soviet Union.

By far Plowshare’s most ambitious project aimed to excavate a new Panama Canal.

Beginning in 1956, the AEC worked with American businesses to innovate a variety of uses for atomic explosives. Many later projects aimed to extract natural gas and shale oil from underground deposits, but initial efforts focused on what officials described simply as “nuclear excavation.” This included massive engineering projects, with bombs being substituted for literal mountains of traditional explosives like TNT.

There were many potential uses. Proposals included the blasting of a harbor in Alaska, the creation of underground water reservoirs in Arizona and the boring of a tunnel for I-40 through California’s Bristol Mountains near Los Angeles, according to historian Scott Kaufman’s book Project Plowshare. The AEC even considered taking the show overseas, with one document on “potential applications of nuclear excavation” — which now resides at the LBJ Presidential Library — discussing everything from the elimination of river rapids in Brazil to the diversion of the Mediterranean into Egypt to produce hydroelectric power.

By far Plowshare’s most ambitious project aimed to excavate a new Panama Canal. Panama had long resented American ownership of the waterway, and the United States feared unrest might disrupt operation of the lock mechanisms that lifted and lowered boats across the spit of land between the Pacific Ocean and the Caribbean Sea. The AEC envisioned a wider, lock-less canal in Nicaragua or Colombia that could better handle modern ships — dug quickly and cheaply by a few hundred atomic blasts. Detonations throughout the 1960s tested how to maximize excavation efficiency without making the surrounding territory a toxic no-man’s-land.

Yet not a single one of these imaginative uses came to pass. Plowshare coincided with the growth of the environmental movement and radiation concerns. The discovery in the 1950s that radioactive isotopes could travel through the atmosphere, fall as rain, taint feed eaten by livestock and enter the human body set off a popular panic that militated against nuclear testing. Johnson even tapped into this fear in a 1964 campaign commercial featuring tainted ice cream, doing little to calm anxiety around the Plowshare program he supported as president.

Blasts were increasingly protested by activists and locals, who were deemed backward “natives” by some blindly enthusiastic government scientists. But Plowshare’s opponents had a point: All tests produced radiation, with a handful accidentally releasing large amounts into the atmosphere. In fact, the new emphasis on natural resource extraction and storage after 1967 partly responded to growing domestic and international objections over potential fallout. According to historian Victor McFarland, mining and extraction tests conducted deep underground “meant that the radioactivity would remain trapped and wouldn’t reach the surface.”

Still, the AEC continued to underestimate radiation levels, and the public’s willingness to endure them. Gasbuggy contaminated the gas it freed and released significant radioactivity when scientists accessed the underground cavity to begin processing. And despite government assurances that products would be safe after sufficient time and treatment, the public fear of isotope-laden fuel — along with tunnels and canals — highlighted the impracticality of the entire project.

The combination of popular disapproval and high costs ultimately doomed Plowshare. After 20 years, in the mid-1970s the besieged program finally shut down. The AEC simply could not overcome the fact that nuclear weapons were designed to cause destruction and alarm. While government scientists had believed they could literally reshape the planet, Plowshare’s legacy today is limited to some largely forgotten data, a few craters out West and shrinking no-drill zones around contaminated underground test sites.