WASHINGTON, June 28 - The National Academy of Sciences published a paper Tuesday describing how terrorists could poison the nation's milk supply, despite a protest from top federal health officials that the publication provides "a road map for terrorists."
The article, by two Stanford University scholars, offers a case study in a continuing debate among scientists over the wisdom of publicizing the country's vulnerabilities. Some scientists believe only an open discussion of weaknesses in defenses against terrorism will prompt the government and the private sector to take action. Others fear Al Qaeda or other enemies could exploit the knowledge to launch attacks.
The six-page paper, called "Analyzing a Bioterror Attack on the Food Supply: The Case of Botulinum Toxin in Milk," was submitted to The Proceedings of the National Academy of Sciences this spring and approved for publication the week of May 30.
The authors, Lawrence M. Wein, a Stanford business professor, and Yifan Liu, a graduate student, suggested that a small quantity of toxin surreptitiously added to a tanker truck loaded with milk might poison hundreds of thousands of Americans.
But on May 27, after the article had already been distributed to some reporters under an embargo, Stewart Simonson, assistant secretary of the Department of Health and Human Services for public health emergency preparedness, wrote to the National Academy of Sciences asking that it not be published.
Mr. Simonson's letter said the article "is a road map for terrorists and publication is not in the interests of the United States." The letter objected to the article's discussion of "vulnerability nodes" in the milk supply chain, the dose of botulinum toxin required to kill or injure large numbers of people and possible inadequacies in milk testing.
The letter said Lester Crawford, the acting commissioner of the Food and Drug Administration, joined in the request not to publish.
Officials of the Academy of Sciences decided to postpone publication to study the matter. On May 30, The New York Times published an Op-Ed article by Dr. Wein summarizing the longer scientific article, with some numbers and details omitted. Dr. Bruce Alberts, the academy's president, wrote in an editorial accompanying the milk article's online publication Tuesday that the academy decided on publication only after meeting with Health and Human Services officials and considering the potential danger.
"All of the critical information in this article that could be useful to a terrorist," Dr. Alberts wrote, is "immediately accessible on the World Wide Web through a simple Google search."
But department officials have not changed their view, said Bill Hall, a spokesman.
"We respect the academy's decision," Mr. Hall said. "But we simply do not agree with their position. If the academy is wrong on this, the consequences could potentially be very dire, and it's going to be H.H.S. and not the academy that has to deal with it."
Dr. Wein, a mathematician who has also written about the potential of smallpox and anthrax attacks, said concerns about his paper were first raised by dairy industry and government officials after he presented it in Washington last September.
"I realize it's a difficult issue - security by obscurity, versus security by transparency," Dr. Wein said. He said he decided to proceed with publication because so much of the information was already public and because he was proposing concrete steps to safeguard the milk supply.
Some experts have asserted that Dr. Wein's paper exaggerates the danger. Dr. Alberts's editorial said recent improvements in pasteurization methods might inactivate far more than 68 percent of the botulinum toxin, the assumption used in the paper.
In addition, Milton Leitenberg of the University of Maryland, and George Smith, of GlobalSecurity.org, have posted a critique of the milk paper on the Web, calling the paper "inflammatory" and asserting that a botulinum toxin attack would be difficult to mount.