Fallout from the Trinity nuclear test

Main article: Trinity (nuclear test)

Trinity test fallout pattern, 12 hours after test, in rads.

Fallout from the Trinity nuclear test in 1945 impacted a broad swath of eastern New Mexico with hundreds of thousands of people exposed to radioactivity. The most-at-risk counties had a population of about 65,000. The priority of the U.S. government was to develop a bomb that could be used to end World War II. The scientists and the military conducting the test had limited insight and paid little attention to the effect of radioactive fallout on the health of local residents. Radioactive fallout was heaviest 20 miles (32 km) to the northeast of the bomb test and in one location at that distance fallout was measured at levels likely to cause serious illness. Not many locations were monitored.

According to studies undertaken decades after the bomb test, cancers attributable to fallout probably numbered several hundred. Anecdotal evidence cites many deaths, especially a high incidence of death among infants born shortly after the test. Compensation by the U. S. to people impacted by later nuclear tests in Nevada did not include New Mexicans impacted by the Trinity nuclear test.

Trinity

The Trinity nuclear test took place on the morning of July 16, 1945 on what is now the White Sands Missile Range in New Mexico. The bomb was detonated on top of a 100 ft (30 m) tower. The bomb contained 13 lb (5.9 kg) of plutonium, but only about three pounds was necessary to create a critical mass of fissionable material for a bomb. The remaining 10 pounds of plutonium was dispersed in the fireball and cloud that followed the blast and climbed to an altitude of an estimated 60,000 ft (18,000 m) into the atmosphere, much higher than the scientists predicted. The explosion also swept up into the fireball hundreds of tons of dirt from below the tower which became highly radioactive. The distribution far and wide of the excess plutonium plus the radioactive dirt gave the Trinity test the characteristics of what would later be called a dirty bomb.

The test was conducted with a maximum of secrecy, but the fireball and the emblematic mushroom cloud were seen as far away as 160 miles (260 km)in Albuquerque and El Paso. The radioactive cloud broke into three parts. One part drifted east, a second west and northwest, and the third and largest to the northeast where it covered an area 100 miles (160 km) long and 30 miles (48 km) wide. The cloud from the blast was visible to near Vaughn, 96 miles (154 km) from the Trinity site.

Groves devised a cover story to be distributed to newspapers to explain what was seen by New Mexicans after the blast. "A remotely located ammunition magazine containing a considerable amount of high explosives and pyrotechnics exploded. There was no loss of life or injury to anyone, and the property damage outside of the explosive magazine itself was negligible. Weather conditions affecting the content of the gas shells exploded by the blast may make it desirable for the Army to temporarily evacuate a few citizens from their homes."

The scientists and the military

Map of the Trinity Site. The highest radiation detected was 20 miles (32 km) to the northeast of the detonation site.

Army officer Leslie Groves led the Manhattan Project to build the bomb. He and a sizeable contingent of scientists and military personnel observed the blast from bunkers constructed 10,000 yd (9,100 m) from the blast site. J. Robert Oppenheimer headed the scientists. They had little insight as to what would happen when the bomb was detonated. Their speculations of what the bomb would yield in its explosion varied from 300 to 45,000 tons of TNT. (In 2021, the yield of the Trinity bomb was calculated to have been 24,800 tons of TNT.) The initial euphoria of the scientists that their work had succeeded faded quickly as they became aware that "something very grave and strong had happened..." In a seminar five days later British mathematician William Penny emphasized the gravity saying that "this [weapon] would reduce a city of three or four hundred thousand people to nothing but a sink for disaster relief, bandages, and hospitals."

The scientists thought that the dangers to the public from the Trinity test "were modest given the proper weather." However, the weather (which was not ideal) became secondary to the desire of President Harry Truman to inform allies of the bomb at the Potsdam Conference, which convened on July 16.

Scientists were aware of the risk of radioactive fallout. Five years before the bomb blast, physicists Otto Frisch and Rudolf Peierls said, "Owing to the spread of radioactive substances with the wind, the bomb could probably not be used without killing large numbers of civilians...[I]t would be very important to have an organization which determines the exact extent of the danger area, by means of ionization measurements, so that people can be warned from entering it." In June 1945, two physicists warned that "radiation effects might cause considerable damage in addition to the blast damage ordinarily considered." One of the scientists, Joseph O. Hirschfelder later said, "very few people believed us when we predicted radioactive fallout from the atom bomb." Less than a month before the Trinity test, Stafford Warren, chief of the medical section of the Manhattan Project, persuaded Groves to assemble a team to track radioactive fallout, "a hasty effort motivated primarily by concern over legal liability." A critic later said that "the spectre of lawsuits haunted the military, and most of the authorities simply wanted to put the whole test and its aftermath out of sight and mind."

General Groves concluded that the Trinity site "is too small for a repetition of a similar test of this magnitude except under very special conditions." He proposed that future tests have a site "with a radius of at least 150 miles without population."

Civilian population

The official report of Los Alamos National Lab said that "wartime pressures to maintain secrecy and minimize legal claims led to decisions that would not likely have been made in later tests." Military and scientific personnel on the scene took precautionary measures to avoid radiation, but the public was not informed nor knowledgeable about the risks. Even though predetermined tolerances for exposure to radioactivity were exceeded, "project staff did not call for evacuations or protective measures." A researcher for the Bulletin of the Atomic Scientists said that "Exposure rates in public areas from the world's first nuclear explosion were measured at levels 10,000 times higher than currently allowed." A monitoring team at Carrizozo, 35 miles (56 km) from the blast site and beneath the radiation cloud, reported at 4:20 pm on July 16 that the radiation level was too high to be measured on the beta-gamma meter. Evacuation of the town was considered, but the radiation cloud passed over quickly.

After the Trinity test, radioactive ash from the explosion fell from the sky for days. In Ruidoso, 50 miles (80 km) from the blast site, white flakes began falling on a group of teenage campers a few hours after the explosion. The falling flakes looked like snow, but were hot, and the youngsters played among them. Barbara Kent, thirteen-years old at the time, said than when she was 30 years old, she was the only survivor of the campers, and that she "had had several cancers, including endometrial cancer and “all kinds of skin cancer.” Tina Cordoba's family lived in Tularosa also 50 miles (80 km) from the blast site. She listed six members of her immediate family who developed cancer after the Trinity test. In 1947, Kathryn S. Behnke, a health provider in Roswell, wrote to Warren, stating there were about 35 infant deaths in the month after the bomb was tested. She said she understood that the number of infant deaths in Alamogordo, closer to the test site, was even larger. Responding to Behnke, an assistant of Warren's said he "wanted to assure you that the safety and health of the people at large is not in any way endangered" and added that he had not heard about an increase in infant deaths.

The heaviest fallout found was at a place dubbed "Hot Canyon", 20 miles (32 km) northeast of the bomb site. The dose on the ground there totalled 139 Rads over a two week period. That is Category Four on the radiation hazard scale, likely to make unprotected people seriously ill, but not die. The fallout in Hot Canyon was observed to settle in a white mist onto some of the livestock in the area, resulting in local beta burns and a temporary loss of dorsal or back hair. Patches of hair grew back discolored white. The Army bought 88 cattle in all from ranchers; the 17 most significantly marked were kept at Los Alamos while the rest were shipped to Oak Ridge for long-term observation. Several other sites northeast of the blast site in an area 12 miles (19 km) long and one mile wide had radioactive levels in Category 3 of the radiation hazard scale which indicates an "increased risk of cancer".

The five New Mexico counties most impacted by radiation were Socorro, Lincoln, Guadalupe, San Miguel, and Torrance which had a combined population of about 65,000 in the mid-1940s. A 2020 study by the National Cancer Institute cited those counties as most at risk and said that several hundred cancers, primarily thyroid cancer, had probably occurred since the blast and more were likely in the future. The study also cited "great uncertainty" due to poor and limited data. For example, New Mexico only began collecting on cancer in 1966 and some cancers develop much quicker than that after radiation exposure.

Legal issues

New Mexicans impacted or possibly impacted by the Trinity test were not included in the 1990 Radiation Exposure Compensation Act (RECA). That act authorized lump sum payments of $50,000 to "downwinders" (people downwind from the nuclear test) and suffering from several designated cancers possibly caused by nuclear tests in Nevada. By 2015, $2 billion had been paid claimants. New Mexican "downwinders" were not included in the law. In 2005, Tina Cordoba, whose parents and grandparents suffered from cancers possibly attributable to the Trinity bomb, founded the Tularosa Basin Downwinders Consortium to lobby the U.S. government for compensation and an apology. New Mexican lawmakers attempted to have New Mexican downwinders included in the law, but in 2024 Speaker of the House Mike Johnson declined to consider an extension of RECA and the law expired.