A rented mailing list used by several charities mistakenly included recipients' religious affiliation on the envelope, offending many who received the letters.
One letter from the Alliance for Retired Americans went to Herbert Kaiser of Palo Alto, who said the religious designation on the envelope reminded him of past labels forced on Jews.
"That's the first thing that popped into my mind when I got that letter," Kaiser told the New York Times.
The fund-raising letter was addressed to "Herbert Kaiser, Jewish."
Kaiser, a former World War II submariner and retired foreign service officer, and at least a dozen other donors complained after getting letters from charitable organizations that identified their religious affiliation on the label. His complaint was first reported in The Washington Post.
The error was traced to a list of donors from the California-based United Farm Workers, which rented the database to other charities. The UFW said it was embarrassed by the incident.
"We feel very badly about it," UFW spokesman Marc Grossman told The Associated Press on Saturday. "It's unclear how many people were affected by it, but even it was one that was offended -- that's too many."
The UFW sent its donor database to Triplex, a data management and collection company that breaks down the information so mailing lists can be shared with other companies and nonprofits.
"We'll take the blame for quality control, because we should have checked the mail before it went out, but we're not the provider of the data," said Fred Vakili, chief administrative officer of infoUSA, Triplex's owner.
Triplex added information, such as religion, to the list of donors at the request of the UFW, Grossman said. The mailing labels included donors names, followed by designations such as "Catholic" and "Hindu."
"Without those breakdowns, many other organizations would not be interested in exchanging or renting our list," Grossman told the Times. "Jewish groups want to send mail to Jewish donors, Catholic groups want to send to Catholics."
But he said the UFW doesn't ask donors directly for religious information and hasn't done a mailing based on religion.
"If we did, we certainly wouldn't place such religious information on the address label," he told The AP. "That would be a gross violation of their privacy."
UFW apologized to individuals and the affected charities, Grossman said. They include the Drug Policy Alliance, SOS Children's Villages, Amnesty International USA and the American Civil Liberties Union.
Grossman said the error came from faulty internal controls at Triplex, citing a Dec. 10 e-mail message from the company. In that e-mail, a Triplex employee wrote: "While processing the update file, our Reformat Department mistakenly moved the religious code to a business name field, which is outputted in the auxiliary address field."
The UFW will use a different database management firm in the future, Grossman said.