The administration “has sought to impose growing restrictions on the free flow of scientific information, unreasonable barriers on the use of scientific materials and increased monitoring of and restrictions on foreign university students,” the ACLU said.

Since the Sept. 11, 2001 attacks the government has actively increased the use of classifying information to keep it secret, including the use of the category “unclassified but sensitive” and extending classification authority to more departments, the ACLU said.

Robert Hopkins of the White House Office of Science and Technology Policy criticized the ACLU for seeking to politicize the issue.

“The report chooses to criticize actions taken to address security concerns in the wake of the 9/11 terrorist attack,” Hopkins said. “The administration has worked in good faith with serious members of the science community, including the National Academies, to determine the best way to enable the conduct of science without providing terrorists with a road map for pursuing their aims.”

Indeed, the National Academy of Sciences delayed publication of an article at the request of the Department of Health and Human Services over concerns the paper could provide terrorists information on poisoning the milk supply. Negotiations over the report are continuing.

But the ACLU contends that the administration has been overzealous, reversing past government openness by creating a presumption of secrecy and lengthening classification periods.

The report lists other science restrictions, including limiting the access of foreign scholars to information, restricting their participation in some areas of research and tightening visa rules with the result of blocking or delaying visits to this country by foreign students and teachers.

And the ACLU charged the administration with trying to suppress information on such topics as global warming, mercury emissions and emergency contraception.