The nation's duty to protect the public from disease could take a back seat to terrorism preparation and response under President Bush's proposed Homeland Security Department, a House panel was told Tuesday.

The General Accounting Office, which is the investigative arm of Congress, said transferring some public health functions from the Health and Human Services Department to the new agency could undermine the basic effort to keep Americans healthy.

"Although HHS programs are important for homeland security, they are just as important to the day-to-day needs of public health agencies and hospitals, such as reporting on disease outbreaks," the GAO said in testimony to the House Energy and Commerce oversight subcommittee.

Bush's plan, the GAO added, "does not clearly provide a structure that ensures that both goals" can be met.

The president's homeland security point man, Tom Ridge, said in his own testimony before the panel that the GAO and many lawmakers had raised "a very important issue," but that both functions could operate smoothly.

If HHS and the new agency disagreed about how to use people and resources -- for example, to respond to both an anthrax attack and a virulent new strain of influenza -- Ridge said the White House would step in.

"If there's a disagreement between Cabinet members ... the ultimate tiebreaker is the president of the United States," Ridge told the House panel.

His testimony followed the release Monday of a National Academy of Sciences report urging the establishment of an in-depth counterterrorism program to protect essential services, from energy delivery to information systems to emergency medicine.

The report provides a blueprint for using science and technology to prevent or reduce the damage from terrorist attacks, said Lewis M. Branscomb of Harvard University, co-chairman of the committee that prepared the study.

"We assume any potential terrorist is looking at all their options, how they might attack us," he said. "We need to think about how to deprive them of those options."

The study noted, "Our society is too complex and interconnected to defend against all possible threats." Still, it called for prompt action to identify and repair the weakest links.

House Science Committee Chairman Sherwood Boehlert, R-N.Y., welcomed the Academy study. He said it is essential to focus research and development and coordinate it within the new Department of Homeland Security.

The Academy report called for "defense in depth," not just perimeter defense or firewalls.

Alan I. Leshner, head of the American Association for the Advancement of Science, which issued a separate report on combating terrorism, stressed the complexity of the problem.

"Yes, terrorism and terrorist acts can come about because of the availability of technology, and you need technology to protect us from terrorist technology," he said.

But Leshner cautioned against restricting openness in scientific communications.

"While protecting ourselves against potential problems, we don't want it to obstruct the future progress in science that we need to advance society," he said.

The massive National Academy report looked at nuclear and radiological threats; possible attacks on human health systems and agriculture; use of toxic chemicals and explosives; the vulnerability of information technology, energy systems, transportation and cities; and the human response to terrorism.

Suggestions for immediate action included:

--Developing improved methods to protect and account for nuclear weapons and other nuclear materials.

--Ensuring the production and distribution of treatments for disease threats.

--Designing and installing in-depth security for transportation, in particular shipping containers and vehicles that carry toxic or flammable materials.

--Improving security for energy distribution systems.

--Developing improved air filtration methods for ventilation systems.

--Ensuring that first responders such as police and fire departments can communicate with one another.

In its separate report, released at the same time as the Academy's findings, the American Association for the Advancement of Science concluded that the nation is poorly prepared to deal with either bioterrorism or attacks on its information systems.

The report by AAAS, the world's largest association of scientists, includes a series of papers looking at the potential hazards of terrorism.

"Bioterrorism is not going to go away," wrote D.A. Henderson, chairman of the Department of Health and Human Services' Council on Public Health Preparedness