Study Shows How Terrorists Could Use Milk to Kill

WASHINGTON —  About a third of an ounce of botulinum toxin poured into a milk truck en route from a dairy farm to a processing plant could cause hundreds of thousands of deaths and billions of dollars in economic losses, according to a scientific analysis published Tuesday despite efforts by federal officials to keep the details secret.

The study by Lawrence M. Wein and Yifan Liu of Stanford University discusses such questions as how terrorists could release the toxin and what effective amounts might be.

Bruce Alberts, president of the National Academy of Sciences, said in an accompanying editorial that a terrorist would not learn anything useful from the article about the minimum amount of toxin to use. “And we can detect no other information in this article important for a terrorist that is not already immediately available to anyone who has access to information from the World Wide Web.”

In fact, he said, publication of the article by the academy could be valuable for biodefense.

The analysis, posted Tuesday on the website of the Proceedings of the National Academy of Sciences, seeks to quantify security weaknesses in the nation’s milk supply chain and makes recommendations for closing those gaps.

Although some of the suggested changes are underway, federal officials thought the material had enough potential for misuse to warrant a last-minute effort to halt publication. That effort, which delayed the report’s unveiling by a month but ultimately failed to keep it from becoming public, proved to be as contentious as the publication itself and assured the report’s place in the scientific canon as one of the first test cases of how to balance scientific freedom and national security in the post-9/11 era.

Wein, whose previous research had forecast the likely effects of terrorist attacks involving anthrax and smallpox, said he was surprised by the government’s push to block publication.

As long ago as last fall, Wein said, he had briefed high-ranking officials of the Departments of Homeland Security and Health and Human Services, along with dairy industry representatives, on his work.

“It was clear the dairy people were nervous about this paper coming out,” Wein said.

But when federal officials did not follow up, he said, he assumed they had concluded that everything in the article was already publicly available and easily obtained through an Internet search.

Bill Hall, a spokesman for HHS, said Tuesday that his department still opposed publication but was not in a position to block release of the data, which were not classified.

“We respect the academy’s position but we don’t agree with it,” Hall said. The “consequences could be dire and it will be HHS, and not the academy, that will have to deal with it.”

The report describes the milk supply chain from cow to consumer. It describes points where a toxin could be introduced, such as a holding tank at a farm, a truck transporting milk to the processing plant or a raw milk holding tank at the plant.

The analysis by Wein and Liu considered what might happen if terrorists poured into a milk tanker truck a couple of gallons of concentrated sludge containing botulinum toxin, a potent bacterial nerve poison now popular in low doses as a wrinkle eraser.

Because milk from many sources is combined in huge tanks, the toxin would get widely distributed and within days be consumed by about 568,000 people, the report concludes.