By harnessing the power of the atom and capturing the potential to unleash divine fire in its hands, humanity understandably developed something of a Prometheus complex when we made the first nuclear bomb. As the Cold War dragged on in the years after World War II, scientists on both sides of the Iron Curtain started looking for ways this new ability could be used for the benefit of humanity, not just to kill everything and render the planet uninhabitable. But we're not talking about nuclear power—no, we're talking about the U.S. government's very real plan to detonate a bunch of nukes in the California desert and blast a highway bypass for Route 66 into existence.
What has to be the most spectacularly violent infrastructure proposal in American history came out of the federal government's Project Plowshare, conceived in 1951 as a way of "beating atomic arms into plowshares." It was our exploration of constructive uses for nuclear weaponry. Bombs detonated underground, officials theorized, could make for cheap ways of moving large volumes of earth—be it for mining, hollowing out caverns to store natural gas, or prepping for other kinds of infrastructure. Dams and reservoirs could be created with single bombs, while dozens-long chains of detonations could carve new canals or even entire harbors.
Project Plowshare was running alongside another massive federal effort in the 1950s and '60s: the birth and rapid expansion of the Interstate Highway System. Really, it was a matter of time before those twin ambitions would collide. And collide they did, in a rugged stretch of the Bristol Mountains in southeast California through which highway planners hoped to route the yet-to-be-completed I-40 as one of America's major east-west corridors and a replacement for dinky old Route 66.
Carryall, an infrastructure proposal under Project Plowshare, began in 1963 while the California Department of Highways (today's Caltrans) was in the early stages of constructing the western end of Interstate 40. Its goal was to sidestep the scenic but slow Route 66, a road that didn't fit into the national defense-supporting highway network advocated by President Eisenhower. A feasibility study conducted by the Atchison, Topeka and Santa Fe Railway—or ATSF—asked the U.S. Atomic Energy Commission for help to build a shortcut through the Bristol Mountains.
Together, with the Commission's San Francisco office and the Department of Energy-funded Lawrence Radiation Laboratory—a U.C. Berkeley offshoot—the study concluded a nuke-excavated bypass would be "technically feasible," and more importantly, "much" cheaper than conventional excavation.
As detailed in the Atomic Energy Commission's 1963 report to Congress, Carryall sought to blast a path through the Bristols about 11 miles north of Amboy—a tourist destination along Route 66—as indicated in the maps above. Here, engineers proposed boring 22 holes along a 10,940-foot stretch of mountainside, each of them 36 inches wide, 343 to 783 feet deep, and lined with corrugated metal. Nuclear devices with yields between 20 and 200 kilotons would be lowered into each of them for a combined yield of 1,730 kilotons, or about 115 times that of the "Little Boy" bomb the U.S. dropped on Hiroshima less than two decades before.
An additional 100-kiloton device would also be detonated nearby to create a drainage basin, preventing flash floods from the nearby Orange Blossom Wash. In displacing an estimated 68 million tons of earth, the blasts would create a canyon with a maximum depth of roughly 350 feet, through which the ATSF railway and the Division of Highways could route two rail lines and up to eight lanes of traffic, respectively.
The planners' outlook was optimistic and their schedule aggressive, with work already underway at the time the Atomic Energy Commission submitted its report to Congress in January of 1964. They expected Carryall's approval later that year, two rounds of detonation to occur in early 1966, and highway construction to begin by the end of 1967. Both the highway and rail routes could be open for traffic as early as 1969.
Dealing With the Nuclear Fallout
But anyone could start digging holes, Carryall's planners had to work out a solution for the biggest side effect of all: dealing with the fallout—figuratively and literally—of setting off almost two dozen nuclear bombs in southeast California. Air and ground shock posed the risk of damaging an aboveground gas pipeline in the area, not to mention the structures in Amboy. The blasts would also throw up clouds of dust estimated to be seven miles wide and 12,000 feet high, which, as they dispersed, could significantly lower visibility as far as 100 miles away, thus forcing highway closures.
Radiological hazards were initially considered minimal, however. "Entry for an eight-hour workday or 40-hour workweek without unusual safeguards will be possible," the feasibility study declared. Citing detonation data from 1962's Project Sedan, the Atomic Energy Commission "estimated that post-shot work in the area could begin after four days," according to the University of Nevada Reno-affiliated Desert Research Institute in a 2011 report.
It all still looked feasible to planners. But to "ensure the proper parameters for Carryall," railway planners decided to wait on results from two other Plowshare experiments that were supposed to run back-to-back: Buggy and Galley.
This pair of row charge tests involved the detonation of several buried nuclear bombs; in Buggy's case, consisting of five identical devices as first outlined in the Atomic Energy Commission's 1962 report to Congress. Data from that experiment would then inform the Galley plan: a more complex test with devices of disparate yields buried across "varying terrain or geology" somewhere in southwest Idaho, according to the Desert Research Institute's report. Galley would be the real dry run for Carryall that would provide "basic data on radioactivity distribution, ground shock, and air blast" to help determine Carryall's potential impact on the California desert.
Neither experiment had been run when work began on Project Carryall in 1963, despite assurances from the Atomic Energy Commission that it would happen. But only "Pre-Buggy" proofs-of-concept with high explosives were executed that year, not the actual nuclear tests, meaning the Galley experiment couldn't proceed. In January 1965, the Commission still sounded optimistic that Buggy (and subsequently Galley) would go ahead, telling Congress in a report it was assumed the Carryall project would be "feasible, safe, and otherwise possible and desirable" based on the "necessary studies and experiments" from Buggy and Galley.
"If mutually satisfactory schedules can be arranged," the Atomic Energy Commission wrote, "the next step in the [Carryall] project would be collection of data on the site and more detailed engineering and safety evaluations."
What initially seemed like a bureaucratic delay in getting the first trial experiment off the ground would soon become a death knell for Project Carryall. The lack of progress created a domino effect that caused it to miss its window; in the Atomic Energy Commission's 1965 report, it declared there had been "no further activities in 1965 in connection with Project Carryall in view of the present incompatibility of the pace of the nuclear excavation development program and the interstate highway construction program."
By that, the Commission meant the California Division of Highways was about out of patience. In September 1966, the Atomic Energy Commission announced I-40 construction through the Bristols would proceed using traditional means—highway officials couldn't wait on Project Plowshare any longer. Though according to the Desert Research Institute, the ATSF railway remained supportive of nuclear excavation through at least May 1970.
Fizzled Out—and for the Better
Whether or not the ATSF held out, the fuse on Carryall would be extinguished in 1973. That year, the California cities of Barstow and Needles were at last united by I-40, according to The San Bernardino Sun. The new stretch of interstate crossed the Bristols only about a mile north from Carryall's proposed detonation site. Carryall's final disarmament was carried out in June 1975, when Project Plowshare was formally terminated by the U.S. Department of Energy. All possibility of beneficial nuclear excavation went with it.
While towns along Route 66 like Amboy were spared the earth-shaking moment of learning their own obsolescence, they met an arguably crueler fate. Its artery of tourism severed, Amboy bled out, dwindling from a population of hundreds to just four people as of a 2015 short film. Maybe it would've been kinder to relocate all of Amboy's residents at once, as some evidence leads us to believe Carryall's bombs could have done.
The first possible reason to uproot Amboy's denizens was over the risk of nuclear fallout, which the Lawrence Radiation Laboratory's 1964 study of nuclear excavation's risks effectively wrote off as a non-issue. It forecasted Carryall's fallout likely fanning eastward from the detonation site, missing Amboy by a couple miles.
Its map, however, may have severely underestimated—if not underrepresented—the risk of irradiating Amboy, according to an Atomic Skies blog post that cited nuclear weapons scientist M. L. Merritt of the Sandia National Laboratories. Merritt apparently believed the fallout would have spread twice as far, and delivered up to five times the projected radiation dosage. He didn't appear to oppose carrying out Carryall, but his criticism gives us reason to question the feasibility study's other impact estimates—which already acknowledged a risk of damaging Amboy's buildings.
In the 1964 Project Plowshare symposium, U.S. Atomic Energy Commission officials projected a pressure wave of up to 4.3 millibars, or just over the threshold to break some glass, according to the National Oceanic and Atmospheric Administration. For comparison, the 15-kiloton Little Boy device detonated over Hiroshima blew out windows as far as 12 miles from ground zero, whereas Amboy would have been just 11 from Carryall's twin blasts of hundreds of kilotons each.
Granted, underground detonations would've shielded Amboy from the worst of the air shock, but the energy channeled into the earth was already of greater concern to officials. The symposium estimated ground shock to range from six to 10 centimeters per second with a damage threshold of eight cm/s; therefore, "minor damage, such as cracked plaster" could happen.
It expected "no large-scale damage," but again, the dubious fallout map casts doubt on this assertion and raises the question of whether Carryall, if rushed, would have resulted in a nuclear disaster.
Such disasters occurred on multiple occasions under the U.S.S.R.'s parallel program, Nuclear Explosions for the National Economy. One seismic sounding test, Kraton-3 in Sakha, Russia, contaminated a Siberian forest's soil with more than twice the average amount of plutonium typical for the Chernobyl exclusion zone, while another, Globus-1, went so awry that Russian media nicknamed it "Ivanovskaya Hiroshima." Had our government caused a nuclear crisis of such scale inside our borders, it might have hastened the populace's turn against nuclear arms, bringing Plowshare to a still-unfulfilled end.
Repurposing arms is a noble goal, one the U.S. proved achievable by adapting the PGM-11 Redstone missile into the Mercury-Redstone 3 rocket, which carried Alan Shepard into space. Neither the U.S. nor the U.S.S.R., however, managed to prove nuclear weapons have real use outside warfare, and if our ongoing nuclear disarmament is anything to go by, we're starting to think they have no place in it now, either.
If there's anything to learn from the failures of Project Plowshare and initiatives like it, it's that we as humans have a tendency to become too enamored with our creations to realize the problems they cause. We're so pleased with ourselves for having made fire that we don't notice how close to our fingertips are to the burning match. Or in this case, an irradiated rest stop in a canyon carved by hubris.
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