Despite decades of denials, government records confirm that the U.S. Census Bureau provided the U.S. Secret Service with names and addresses of Japanese-Americans during World War II.

The Census Bureau surveys the population every decade with detailed questionnaires but is barred by law from revealing data that could be linked to specific individuals. The Second War Powers Act of 1942 temporarily repealed that protection to assist in the roundup of Japanese-Americans for imprisonment in internment camps in California and six other states during the war. The Bureau previously has acknowledged that it provided neighborhood information on Japanese-Americans for that purpose, but it has maintained that it never provided "microdata," meaning names and specific information about them, to other agencies.

A new study of U.S. Department of Commerce documents now shows that the Census Bureau complied with an August 4, 1943, request by Treasury Secretary Henry Morgenthau for the names and locations of all people of Japanese ancestry in the Washington, D.C., area, according to historian Margo Anderson of the University of Wisconsin–Milwaukee and statistician William Seltzer of Fordham University in New York City. The records, however, do not indicate that the Bureau was asked for or divulged such information for Japanese-Americans in other parts of the country.

Anderson and Seltzer discovered in 2000 that the Census Bureau released block-by-block data during WW II that alerted officials to neighborhoods in California, Arizona, Wyoming, Colorado, Utah, Idaho and Arkansas where Japanese-Americans were living. "We had suggestive but not very conclusive evidence that they had also provided microdata for surveillance," Anderson says.

The Census Bureau had no records of such action, so the researchers turned to the records of the chief clerk of the Commerce Department, which received and had the authority to authorize interagency requests for census data under the Second War Powers Act. Anderson and Seltzer discovered copies of a memo from the secretary of the treasury (of which the Secret Service is part) to the secretary of commerce (who oversees the Census Bureau) requesting the data, and memos documenting that the Bureau had provided it [see image below].

The memos from the Bureau bear the initials "JC," which the researchers identified as those of then-director, J.C. Capt.

"What it suggests is that the statistical information was used at the microlevel for surveillance of civilian populations," Anderson says. She adds that she and Seltzer are reviewing Secret Service records to try to determine whether anyone on the list was actually under surveillance, which is still unclear.

"The [new] evidence is convincing," says Kenneth Prewitt, Census Bureau director from 1998 to 2000 and now a professor of public policy at Columbia University, who issued a public apology in 2000 for the Bureau's release of neighborhood data during the war. "At the time, available evidence (and Bureau lore) held that there had been no release of microdata," he says. "That can no longer be said."

The newly revealed documents show that census officials released the information just seven days after it was requested. Given the red tape for which bureaucracies are famous, "it leads us to believe this was a well-established path," Seltzer says, meaning such disclosure may have occurred repeatedly between March 1942, when legal protection of confidentiality was suspended, and the August 1943 request.

Anderson says that microdata would have been useful for what officials called the "mopping up" of potential Japanese-Americans who had eluded internment.

The researchers turned up references to five subsequent disclosure requests made by law enforcement or surveillance agencies, including the Federal Bureau of Investigation, none of which dealt with Japanese-Americans.

Lawmakers restored the confidentiality of census data in 1947.

Officially, Seltzer notes, the Secret Service made the 1943 request based on concerns of presidential safety stemming from an alleged March 1942 incident during which an American man of Japanese ancestry, while on a train from Los Angeles to the Manzanar internment camp in Owens Valley, Calif., told another passenger that they should have the "guts" to kill President Franklin Delano Roosevelt.

The incident occurred 17 months before the Secret Service request, during which time the man was hospitalized for schizophrenia and was therefore not an imminent threat, Seltzer says.

The disclosure, while legal at the time, was ethically dubious and may have implications for the 2010 census, the researchers write in a paper presented today at the annual meeting of the Population Association of America held in New York City. The U.S. has separate agencies for collecting statistical information about what people and businesses do, and for so-called administrative functions—taxation, regulation and investigation of those activities.

"There has to be a firewall in some sense between those systems," Anderson says. If a company submits information ostensibly for documenting national economic growth but the data ends up in the antitrust division, "the next time that census comes they're not going to get that information," she says.

Census data is routinely used to enforce the National Voting Rights Act and other policies, but not in a form that could be used to identify a particular person's race, sex, age, address or other information, says former director Prewitt. The legal confidentiality of census information dates to 1910, and in 1954 it became part of Title 13 of the U.S. Code, which specifies the scope and frequency of censuses.

"The law is very different today" than it was in 1943, says Christa Jones, chief of the Census Bureau's Office of Analysis and Executive Support. "Anything that we release to any federal agency or any organization all of those data are reviewed," she says, to prevent disclosures of individual information.

The Census Bureau provided neighborhood data on Arab-Americans to the U.S. Department of Homeland Security in 2002, but the information was already publicly available, Jones says. A provision in the controversial Patriot Act—passed after the 9/11 attacks and derided by critics as an erosion of privacy—gives agencies access to individualized survey data collected by colleges, including flight training programs.

The Census Bureau has improved its confidentiality practices considerably in the last six decades, former director Prewitt says. He notes that census data is an increasingly poor source of surveillance data compared with more detailed information available from credit card companies and even electronic tollbooths.

Nevertheless, he says, "I think the Census Bureau has to bend over backwards to maintain the confidence and the trust of the public." Public suspicion—well-founded or not—could undermine the collection accurate census data, which is used by sociologists, economists and public health researchers, he says.

"I'm sad to learn it," he says of the new discovery. "It would be sadder yet to continue to deny that it happened, if, as now seems clear, it did happen. You cannot learn from and correct past mistakes unless you know about them."