The first people known to have been exposed to radiation by the U.S. Navy in San Francisco were part of an atomic cleanup crew.
Wrapped in cotton overalls and clunky gas masks, with pockets sewn shut and canvas booties covering their shoes, workers from the Navy’s shipyard at Hunters Point in late 1946 began to board ships irradiated by an atomic bomb test over the summer. Their job was to “decontaminate” the vessels, which meant scraping and sandblasting potentially deadly plutonium and fission byproducts off paint, metal and wood.
They knew the work was dangerous. They did not know they were among the first participants in a vast, years-long science experiment.
- 1. OVERVIEW: How a San Francisco Navy Lab Became a Hub for Human Radiation Experiments • List of Studies
- 2. THE DECISION-MAKERS: After Atomic Test Blunder, Government Authorized Study of Radiation in Humans
- 3. THE STUDIES: Human Radiation Studies Included Mock Combat, Skin Tests and a Plan to Inject 49ers
- 4. ETHICS: Cold War Scientists Pushed Ethical Boundaries With Radiation Experiments
- 5. FADING HISTORIES: Destroyed Records, Dying Witnesses Consign San Francisco Radiation Lab to Obscurity
- 6. PERPETUAL EXPERIMENT: Shuttered Radiation Lab Poses Ongoing Health Risks for Growing Neighborhood
- 🎧 Podcast Episode 1: A Community of Color Contends With the Navy’s Toxic Legacy
- 🎧 Podcast Episode 2: Why the Navy Conducted Radiation Experiments on Humans
Both the decontamination and the special clothing were part of a research agenda, Navy Cmdr. K.J. Hoffman, an officer assigned to what would become a major radiation laboratory, wrote in a December 1946 memo to superiors at the Pentagon. While the workers tried to clean the ships so they could be pressed back into service or sold for scrap, the Navy’s new San Francisco lab would “conduct suitable experiments” to determine if the protective outfits and other measures were adequate, Hoffman wrote.
Hoffman’s missive is one of the earliest documents showing that officials intended to conduct atomic research at the lab that would include exposing humans to radiation, a risky act with unknown consequences. The military staked human health on a gamble meant to glean badly needed information about how nuclear war might affect people and their surroundings, and discover if there was any hope of defense against such an onslaught.
This investigative series details how the U.S. Naval Radiological Defense Laboratory, based at the Hunters Point Naval Shipyard in San Francisco, exposed at least 1,073 dockworkers, military personnel, lab employees and others to radiation in technical exercises and medical experiments early in the Cold War.
A review of thousands of pages of government and academic records by the San Francisco Public Press shows scientists there conducted at least 24 studies exposing humans to radiation from 1946 to 1963, nearly three times more than a federal inquiry acknowledged decades later. Researchers reported dozens of safety violations without any apparent repercussions. There is no evidence the government tracked the long-term effects on study participants, or on residents of the historically African American neighborhood who have long suspected their health problems were connected to pollution from the lab.
In Part 2, we examine public records that prove that exposing humans to radiation was part of the known cost of the lab’s research program, a toll accepted by top military and civilian brass at every level of the chain of command, from Washington down to the docks.
What started as a rushed, ad-hoc effort led from makeshift waterfront quarters would grow in scope and ambition over the next decade and a half to become a sophisticated, multimillion-dollar operation — and one of the most important atomic research outfits in the Pentagon’s orbit.
The lab was part of an effort to “develop how the United States might actually use nuclear weapons,” said Gabrielle Hecht, a history professor at Stanford University who has taught a course and led research focused on the shipyard, and who led an archival project documenting the burden of radioactive waste in the Bayview-Hunters Point neighborhood.
“One of the ironies,” Hecht said, “is the active decontamination actually involved spreading the contamination in ways they were not able to control — and perhaps did not attempt to control.”
TOWING THE COLD WAR HOME
While strangers embraced in the streets to celebrate the end of World War II, the Navy confronted an existential crisis. Sea power had done most of the fighting in the Pacific, only to see the war won by a technological terror dropped from an airplane.
Fear that nuclear weapons made fighting ships obsolete motivated the Navy to lobby for Operation Crossroads, the first postwar weapons test and “the largest scale laboratory experiment in history,” as a shipyard commanding officer described it a decade later.
To see if the fleet could survive an atomic attack, in July 1946 the Navy planned to hit more than 90 surplus warships anchored at Bikini Atoll in the Pacific Ocean with plutonium bombs. One, dropped from a B-29 bomber, the same model of plane that delivered the devices that destroyed Hiroshima and Nagasaki, missed its target by a half mile. The other, detonated underwater, created “the world’s first nuclear disaster,” in the words of Glenn Seaborg, a scientist at the Manhattan Project, the U.S. government’s secret wartime atomic bomb program. (Seaborg was not counting the two bombs dropped on Japan the previous year.) Dozens of ships remained afloat but were poisoned by a rolling radioactive wave that also threatened tens of thousands of observers aboard support vessels.
A planned third shot was canceled. But for the Navy, catastrophe presented opportunity. In the vessels lurked invaluable data on the aftermath of nuclear explosions and what defenses, if any, might be useful. Whoever could extract that data would be a major player in the atomic weapons program. Since the ships were the Navy’s, so was the data.
“The main question was whether to use some place already in existence, or set up an entirely new headquarters” to study them, according to an official history of the lab📄 published in 1958. The heavily militarized Bay Area, which included five Navy bases, had the dock space to host the radioactive ships. And the Bay Area was already a hub for atomic research — including human experimentation.
Scientists plucked from research labs at the University of California, Berkeley, provided much of the brainpower behind the Manhattan Project. And the military was already working with Joseph Hamilton, a physician trained at the University of California, San Francisco, and educated as a chemist at Berkeley. He previously led a series of biology experiments that injected unsuspecting patients with plutonium at hospitals in Berkeley and San Francisco.
Notoriously cavalier about radiation exposure — colleagues would later recall with amazement how he would casually lean against unshielded particle accelerators and other sources of cell-destroying energy — Hamilton died in 1957 of leukemia, at age 49. Records from meetings held in Washington, D.C., in October and November 1946 show that when the Navy was pondering what to do at the lab and how much radiation they could expose people to, it consulted Hamilton.
From the beginning, Hamilton dismissed safety standards📄, which he called, according to meeting minutes, “mainly guess work and calculated risk.” He also dissuaded Navy officials from asking too many other scientists their opinion on the matter, since “the more advisers the more ridiculous the standards because of the personal variation in opinions of safe limits.”
Vessels still contaminated were to be returned to service, sold for scrap or preserved for research. Hamilton is on record saying that when spots with plutonium were painted over, they would “not present a hazard.”
Some of the same junior officers assigned to oversee the decontamination work in San Francisco took their first radiation dose in the Pacific, either by viewing the July bomb blasts or participating in recovery efforts that began in August. Exactly how much was unknown, as only 18,875 film dosimeters, strips of material that change color when exposed to radiation (at the time the best and cheapest measure), were available for the more than 42,000 people present at Bikini. The 1958 official lab history bragged about how little the lab had to work with: “Their equipment consisted of one coffee pot and six Geiger counters, only two of which worked.”
As more ships arrived, Rear Adm. Clifford A. Swanson, the Navy’s top doctor, outlined safety regulations in a memo dated Jan. 31, 1947. In contrast to Hamilton, Swanson seemed to grasp the gravity of the situation and had a sophisticated understanding of how radiation worked.
Workers aboard the ships were at risk of inhaling radioactive particles. Health complications “might not appear for many years,” said a memo from Swanson’s office📄. “Even when the exposure is not of such an order as to cause death, it may cause tumors of various tissues which may be disabling. This subtle, lurking hazard requires respect.”
Two weeks later, a memo from Swanson’s office issued further orders: The Navy would send medics and doctors to conduct “radioactive counts on urines” and stools of men who had been aboard the vessels. Results would be recorded in a special set of medical files kept by the lab, distinct from the workers’ regular health records.
Some workers did not share Swanson’s concern and had been pocketing pieces of the radioactive ships as mementos. Others were photographed sitting by the docks, masks off and eating lunch a stone’s throw from radioactive ships. It was common for workers to be lackadaisical about masking. A memo from Aug. 27 that year underscored the danger📄. “Careful policing aboard target ships,” it said, “is required to insure strict mask discipline.”
But Swanson signaled that some level of human exposure to radiation was an acceptable risk, as long as it was spread around. He had ordered in his January safety memo that “a sufficient number of personnel must be employed to assure that all individuals be exposed to the least possible degree.” The workers would wear dosimeters similar to the ones at Bikini. Anyone whose clothing or protective gear was damaged would be removed from the job. And anyone foolish enough to try to palm a hunk of a hot ship would be in trouble. “The practice of souvenir hunting must be absolutely suppressed,” he wrote📄.
EXPANDED MISSION
The February 1947 memo from Swanson’s office, signed by naval physician George M. Lyon, encouraged researchers to think bigger than just monitoring shipyard workers. It offered a wide range of objectives for the lab to pursue, including “the establishment of levels of maximum permissible exposures and total dosage.”
While requesting “observations on personnel in regular contact with ex-target vessels,” the memo called for “investigations of toxicity of fissionable materials, fission products, and their chemical compounds, including biological studies.”
This was all well beyond ship decontamination. It was also the first known official mandate for the lab to study the effects of radiation on living organisms — including humans.
Five monthly radiological safety reports📄, published from 1948 to 1950, survive. They chronicle workers’ and sailors’ exposure based on urine tests. The Public Press found copies at the National Archives branch document repository in San Bruno, a few miles south of the San Francisco shipyard, and the Department of Energy’s Nuclear Testing Archive in Las Vegas.
The technology used back then to monitor radiation exposure, the badges of film that changed color, was unreliable. But there were still safety standards for the lab to follow.
Total exposure was measured in units called roentgen. The “absorbed dose” a person might be exposed to was measured in rad, short for “radiation absorbed dose.” The “dose equivalent,” meant to convey how much radiation a person received as well as its medical effect, was measured in rem, short for “roentgen equivalent man.”
According to the U.S. Nuclear Regulatory Commission, “for practical purposes,” exposure to 1 roentgen of gamma radiation — high-energy photons that can cause DNA damage, cell mutations and cancer — will result in an absorbed dose of 1 rad and a dose equivalent of 1 rem. That is roughly on par with the X-ray radiation someone would receive during a full-body CT scan, though exact dosage depends on factors including distance from the source and the type of radiation.
That level is also what some modern-day researchers say is a minimum threshold leading to negative health outcomes, though others argue that even lower doses could be harmful. However, clinicians do stress that medical procedures using radiation come with therapeutic benefits that often exceed the health risks.
Lab records show that seven shipyard workers decontaminating the Operation Crossroads vessels were exposed to in excess of 1 roentgen. Six were identified by last names and first initials, with one person’s name entirely redacted. A worker named B.R. Bishop absorbed 4.04 rem of gamma radiation📄 during 630 hours spent onboard by July 1948.
Though at the time it broke no laws, Bishop’s exposure was in excess of standards that emerged the following decade, when the lab was asking the Atomic Energy Commission for permission to expose more humans.
By 1958, federal standards limited exposure to 3 rem over a 13-week period. A more complicated formula regulated lifetime exposure, with younger people’s exposure more limited, but 12 rem per year was the maximum.
Americans today receive a dose of about 0.62 rem of radiation every year from background, medical and other sources, according to the Environmental Protection Agency. For adults working in environments where radiation exposure is an occupational hazard, federal law forbids an annual whole-body dose greater than 5 rem, as it has since 1960.
Anything close to 5 rem per year “is not good,” said Alex Wellerstein, a nuclear historian at the Stevens Institute of Technology in Hoboken, N.J. “That adds to your overall cancer chances. If you get your yearly dose, you really don’t want to pick up any more.”
Four years’ worth of the San Francisco Navy lab’s “radiological safety” reports, in 1956📄, 1958📄, 1959📄 and 1960📄, obtained via a Freedom of Information Act request, record 33 instances of exposures in excess of federal standards at the time. The highest full-body dose recorded was more than 7 rem.
Some were accidental or at least unintended, as in the case of the unnamed worker who held a door to a radiation source open while conducting a test. Others were deemed essential and done deliberately, like the workers at Camp Parks, an Army base in Dublin, Calif., sent into a restricted zone to fix equipment in 1960.
Lab officials reported the overexposures to the Atomic Energy Commission and the Pentagon and acknowledged a need to do better: “Changes are being made.”
Images from the series
NUCLEAR COMPETITION
The Hunters Point lab helped the Navy secure its relevance as one of the three legs in the military’s modern-day “nuclear triad”: land-based missiles, bombs carried by airplanes and submarine-deployed nukes. Studying radioactive ships and the people aboard them gave the service an advantage in its internecine struggle with the Army and Air Force.
The entire Pentagon was engaged in a separate feud — with the Atomic Energy Commission, the bureaucracy created in 1947 as the civilian successor to the Manhattan Project — over command and control of the nuclear arsenal. Yet the commission appreciated the potential of the Navy’s lab, which earned endorsements from top scientists. On Oct. 27, 1947, researcher William Sullivan, who was to become the lab’s first scientific director, outlined his vision.
“In the simplest possible statement, the objective of the Laboratory is to study the defensive aspects of atomic warfare,” Sullivan wrote📄 in a letter to the commission’s Paul McDaniels. The lab would participate in future nuclear weapons tests. This meant the Navy, which would provide logistical support as well as data collection and analysis, was relevant indeed.
It was also a sign that the catastrophe at Crossroads was, if not forgotten, at least forgiven. And it was more indication that exposure was an accepted cost of the weapons program.
The lab would write radiological defense manuals and develop respirators and other personal protective equipment required to work, fight or simply survive around nuclear material or radiation from a bomb, Sullivan wrote. The lab would determine human tolerance to radiation and, in anticipation of a wartime scenario, perform “studies leading to the predictions of the performance of personnel who might receive sub-lethal acute doses under certain tactical situations and who must perform useful services thereafter.”
By the end of 1948, most Crossroads ships were “disposed of” — used as targets in other exercises, sold for scrap or simply scuttled — whether or not they were “decontaminated.” Others would remain anchored at Hunters Point. The USS Independence, a light aircraft carrier, served as a floating lab and radioactive waste dump before being deliberately sunk off the Farallon Islands west of San Francisco a few years later.
Other branches of the military wanted to pursue atomic research projects, like studying how to fight in a radioactive battlefield or fly planes in radioactive clouds. That meant they had to pitch the Navy.
The lab was the “only military organization actively carrying out research in the field of radiological decontamination,” Army Gen. Kenneth David Nichols, chief of the Armed Forces Special Weapons Project, the Pentagon’s nuclear-weapons bureaucracy, acknowledged in a memo📄 on Dec. 13, 1948. Rather than each service building its own operations from scratch, “The Navy Department should continue its research program at the NRDL with increased participation by both the Army and the Air Force,” he added, using the radiation lab’s initials. Other branches’ “research projects deemed necessary in this field” would be assigned to it.
An Army officer tasked with “the development of practical field applications” had already contacted the lab. During a January 1948 visit, Army Capt. D.F. Kimbel made arrangements “for future liaison in connection with field tests” based on the lab’s research. The Army needed data about fighting in atomic war zones, but only the Navy had a dedicated research facility where this question could be pursued.
That was how Army soldiers like Cpl. Eldridge Jones would be ordered to shovel radioactive dirt created by the San Francisco lab, under the scientists’ close supervision.
Additional reporting by Rebecca Bowe. Listen to Episode 1 and Episode 2 of her podcast.
A series investigating the forgotten history of Cold War San Francisco
The San Francisco Public Press sifted through thousands of pages of obscure records, interviewed experts and tracked down elderly veterans who were subjected to ethically questionable radiation exposure by the U.S. Navy in San Francisco during the Cold War. What we found reveals a troubling history with effects still felt today.
Reporting: Chris Roberts and Rebecca Bowe | Editing: Michael Stoll and Liz Enochs | Research Editing: Ambika Kandasamy | Web Design: John Angelico | Copy Editing: Kurt Aguilar, Michele Anderson and Richard Knee | Archival Research and Illustration: Stacey Carter | Audio Editing: Liana Wilcox, Mel Baker and Megan Maurer | Sound Gathering: Justin Benttinen | Photography: Sharon Wickham, Yesica Prado and Guillermo Hernandez | Graphic Design: Reid Brown | Fact Checking: Dani Solakian and Ali Hanks | Proofreading: Lila LaHood, Noah Arroyo, Zhe Wu and Sylvie Sturm | Special thanks to Alastair Gee and Danielle Renwick at The Guardian and Ben Trefny at KALW Public Radio, and to Laura Wenus and Amy Pyle
Funding for “Exposed” comes from the California Endowment, the Fund for Environmental Journalism, the Local Independent Online News Publishers Association and members of the San Francisco Public Press. Learn more at sfpublicpress.org/donate.
