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.

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.

Read the rest of this story, listen to the two-episode podcast, review primary documents and see historical images through the links below. Watch for more stories coming in December.

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EXPOSED: THE HUMAN RADIATION EXPERIMENTS AT HUNTERS POINT | A series investigating the forgotten history of Cold War San Francisco

1. OVERVIEW: How a San Francisco Navy Lab Became a Hub for Human Radiation Experiments • List of Studies

🎧 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

2. THE DECISION-MAKERS: After Atomic Test Blunder, Government Authorized Study of Radiation in Humans

COMING SOON:

3. THE STUDIES: Human Radiation Studies Included Mock Combat, Skin Tests and a Plan to Inject 49ers [Dec. 4]

4. ETHICS: Cold War Scientists Pushed Ethical Boundaries With Radiation Experiments [Dec. 6]

5. FADING HISTORIES: Destroyed Records, Dying Witnesses Consign San Francisco Radiation Lab to Obscurity [Dec. 9]

6. PERPETUAL EXPERIMENT: Shuttered Radiation Lab Poses Ongoing Health Risks for Growing Neighborhood [Dec. 11]