The researchers also suggested they were open to increased oversight to prevent misuse of research in the life sciences, but that governmental intervention would not be welcome.

The council, working with the American Association for the Advancement of Science, sent surveys in 2007 to 10,000 AAAS members to assess their thoughts on "dual-use" biological research that produces vaccines and other clear benefits but also expertise, tools and procedures that could be misused. A total of 3,524 scientists submitted full or partial responses.

In response to a question asking for the percent chance that terrorists would conduct a biological attack somewhere in the world in the next five years, the scientists returned an average estimate of 51 percent. They also estimated a 35 percent chance of such an attack occurring in the United States during the time frame.

Respondents -- most of whom were in the biological, health and agricultural sciences -- said there was only a 28 percent likelihood that complicated dual-use research would "facilitate" an incident. The study indicated that scientists believe terrorists would instead use relatively primitive methods.

"There was more concern about information available on the Internet than there might be in scientific journals relating to potential dual use," University of Louisville biology and public health professor Ronald Atlas, chairman of the panel that conducted the survey, said yesterday at the report's official release. Extremists were seen as "more likely to use the low-hanging fruit that was easy to access and simple to use than to deal with ... than the high-end biotech potential for the creation of real weapons of mass destruction," he said.

Responses to the risk questions, however, were "not normally distributed," the report says. It notes that
the most common answer to to the global-threat question was that the chance of an attack was
50 percent, while the second-most common answer was 100 percent. That estimate was made by nearly as many respondents as those who answered 50 percent.

The survey did not ask the scientists for the reasoning behind their threat perceptions, Atlas said. He noted that the assessment of the immediacy of the threat against the United States appeared less dire than those issued recently by the Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism and former Vice President Dick Cheney.

"I'm not saying who's right and who's wrong in this, but there's a difference of perception," Atlas said.

Atlas added the caveat that the limited number of responses -- less than half of the surveys sent out were returned -- makes it impossible to generalize the results across the field of science. There is also the potential for bias in the findings, if scientists who conduct biological defense research or work with diseases that are characterized as bioterrorism agents made up a significant number of the respondents.

Today's concerns regarding certain areas of science were spurred largely by the terrorist attacks of Sept. 11, 2001, and the anthrax mailings that followed that year. Helping to sustain those worries have been several research projects in recent years that raised security concerns, including the recreation of the massively lethal 1918 influenza virus and an analysis of the use of botulinum toxin to taint the U.S. milk supply. Advances in microbe engineering and other scientific endeavors have also been cause for anxiety.

The National Science Advisory Board for Biosecurity, a federal panel of science and security professionals, defined "dual-use research of concern" as "research that based on current understanding can be reasonably anticipated to provide knowledge, products or technologies that could be directly misapplied by others to pose a threat to public health, safety, agricultural crops and other plants, animals, the environment or materiel."

Science professionals have addressed the question in various fashions in the United States and around the world, said Atlas and fellow survey panel member David Franz, chief biological scientist at the Midwest Research Institute in Frederick, Md.

A number of scientific journals have enacted guidelines to reduce the likelihood that published research could be put to bad uses. Meanwhile, the advisory board and other experts panels have encouraged increased education within the scientific community on the dual-use threat, development of a code of conduct for the life sciences and a heightened review system for potentially sensitive research, among other measures.

"There's a subset of the scientific population that is very actively involved, but there's a broader population that I think is less involved," Franz said. "That, I think, was really the purpose of ... this survey, to attempt to understand the thinking of that broader community."

The panel found, to its surprise, that some scientists had taken voluntary measures to address concerns regarding dual-use dangers. A total of 260 respondents indicated that at some point they had suspended collaboration with other scientists, chosen against a particular project or decided not to communicate a finding.

"It suggests that the community, at least a portion of it, is both aware and responding," Atlas said. "What we are not sure of ... is whether those responses are in fact appropriate. Were the individuals who changed their research activities responding to a bona fide concern ... or were they simply paranoid?"

The survey found significantly more support among the responding scientists for self-governance than for mandatory government oversight. Eighty-two percent of those surveyed backed development of codes of conduct by professional science organizations, while only 26 percent said they saw the necessity for increased government monitoring of dual-use research.

If the government does step in, scientists indicated they would find restrictions on access to biological material or mandatory certification of research personnel less objectionable than controls on communication of research findings.

The report calls for more discussion among life scientists of dual-use research and for publications and professional groups to more effectively communicate any biosecurity guidelines. There is also a need for improved and additional education, along with new surveys that would provide a broader perspective on the issue and address the question of bias in the results, the panel said.

"I'm encouraged with the results of this survey, that there is in fact a level of awareness among the scientific community of these issues, whether it be clear or not or muddle or not, nonetheless those you surveyed were aware of it," said Carol Blum, research compliance and administration director at the Council on Governmental Relations.