We have learned little from the cataclysms of September 11 and Hurricane Katrina. When it comes to catastrophe, America is living on borrowed time--and squandering it.

The truth is, acts of terror cannot always be prevented, and nature continues to show its fury in frighteningly unpredictable ways. Resiliency, argues Flynn, must now become our national motto. With chilling frankness and clarity, Flynn paints an all-too-real scenario of the threats we face within our own borders. A terrorist attack on a tanker carrying liquefied natural gas into Boston Harbor could kill thousands and leave millions more of New Englanders without power or heat. The destruction of a ship with a cargo of oil in Long Beach, California, could bring the West Coast economy to its knees and endanger the surrounding population. But even these alarmingly plausible terrorist scenarios pale in comparison to the potential destruction wrought by a major earthquake or hurricane.

Our growing exposure to man-made and natural perils is largely rooted in our own negligence, as we take for granted the infrastructure handed down to us by earlier generations. Once the envy of the world, this infrastructure is now crumbling. After decades of neglect, our public health system leaves us at the mercy of microbes that could kill millions in the next flu pandemic. Flash flooding could wipe out a fifty-year-old dam north of Phoenix, placing thousands of homes and lives at risk. The next San Francisco earthquake could destroy century-old levees, contaminating the freshwater supply that most of California relies on for survival.

It doesn't have to be this way. The Edge of Disaster tells us what we can do about it, as individuals and as a society. We can--and, Flynn argues, we must--construct a more resilient nation. With the wounds of recent national tragedies still unhealed, the time to act is now. By tackling head-on, eyes open the perils that lie before us, we can remain true to our most important and endearing national trait: our sense of optimism about the future and our conviction that we can change it for the better for ourselves--and our children.

In 1920, the Irish Republican Army reportedly considered a terrifying new weapon: typhoid-contaminated milk. Reading from an IRA memo he claimed had been captured in a recent raid, Sir Hamar Greenwood described to Parliament the ease with which "fresh and virulent cultures" could be obtained and introduced into milk served to British soldiers. Although the plot would only target the military, the memo expressed concern that the disease might spread to the general population.

Although the IRA never used this weapon, the incident illustrates that poisoning a nation's milk supply with biological agents hardly ranks as a new concept. Yet just two weeks ago, the National Academy of Sciences' journal suspended publication of an article analyzing the vulnerability of the U.S. milk supply to botulinum toxin, because the Department of Health and Human Services warned that information in the article provided a "road map for terrorists."

That approach may sound reasonable, but the effort to suppress scientific information reflects a dangerously outdated attitude. Today, information relating to microbiology is widely and instantly available, from the Internet to high school textbooks to doctoral theses. Our best defense against those who would use it as a weapon is to ensure that our own scientists have better information. That means encouraging publication.

The article in question, written by Stanford University professor Lawrence Wein and graduate student Yifan Liu, describes a theoretical terrorist who obtains a few grams of botulinum toxin on the black market and pours it into an unlocked milk tank. Transferred to giant dairy silos, the toxin contaminates a much larger supply. Because even a millionth of a gram may be enough to kill an adult, hundreds of thousands of people die. (Wein summarized the article in an op-ed he wrote for the New York Times.) The scenario is frightening, and it is meant to be -- the authors want the dairy industry and its federal regulators to take defensive action.

The national academy's suspension of the article reflects an increasing concern that publication of sensitive data can provide terrorists with a how-to manual, but it also brings to the fore an increasing anxiety in the scientific community that curbing the dissemination of research may impair our ability to counter biological threats. This dilemma reached national prominence in fall 2001, when 9/11 and the anthrax mailings drew attention to another controversial article. This one came from a team of Australian scientists.

Approximately every four years, Australia suffers a mouse infestation. In 1998, scientists in Canberra began examining the feasibility of using a highly contagious disease, mousepox, to alter the rodents' ability to reproduce. Their experiments yielded surprising results. Researchers working with mice naturally resistant to the disease found that combining a gene from the rodent's immune system (interleukin-4) with the pox virus and inserting the pathogen into the animals killed them -- all of them. Plus 60 percent of the mice not naturally resistant who had been vaccinated against mousepox.

In February 2001 the American SocietyforMicrobiologists' (ASM) Journal of Virology reported the findings. Alarm ensued. The mousepox virus is closely related to smallpox -- one of the most dangerous pathogens known to humans. And the rudimentary nature of the experiment demonstrated how even basic, inexpensive microbiology can yield devastating results.

When the anthrax attacks burst into the news seven months later, the mousepox case became a lightning rod for deep-seated fears about biological weapons. The Economist reported rumors about the White House pressuring American microbiology journals to restrict publication of similar pieces. Samuel Kaplan, chair of the ASM publications board, convened a meeting of the editors in chief of the ASM's nine primary journals and two review journals. Hoping to head off government censorship, the organization -- while affirming its earlier decision -- ordered its peer reviewers to take national security and the society's code of ethics into account.

Not only publications came under pressure, but research itself. In spring 2002 the newly formed Department of Homeland Security developed an information-security policy to prevent certain foreign nationals from gaining access to a range of experimental data. New federal regulations required that particular universities and laboratories submit to unannounced inspections, register their supplies and obtain security clearances. Legislation required that all genetic engineering experiments be cleared by the government.

On the mousepox front, however, important developments were transpiring. Because the Australian research had entered the public domain, scientists around the world began working on the problem. In November 2003, St. Louis University announced an effective medical defense against a pathogen similar to -- but even more deadly than -- the one created in Australia. This result would undoubtedly not have been achieved, or at least not as quickly, without the attention drawn by the ASM article.

The dissemination of nuclear technology presents an obvious comparison. The 1946 Atomic Energy Act classifies nuclear information "from birth." Strong arguments can be made in favor of such restrictions: The science involved in the construction of the bomb was complex and its application primarily limited to weapons. A short-term monopoly was possible. Secrecy bought the United States time to establish an international nonproliferation regime. And little public good would have been achieved by making the information widely available.

Biological information and the issues surrounding it are different. It is not possible to establish even a limited monopoly over microbiology. The field is too fundamental to the improvement of global public health, and too central to the development of important industries such as pharmaceuticals and plastics, to be isolated. Moreover, the list of diseases that pose a threat ranges from high-end bugs, like smallpox, to common viruses, such as influenza. Where does one draw the line for national security?

Experience suggests that the government errs on the side of caution. In 1951, the Invention Secrecy Act gave the government the authority to suppress any design it deemed detrimental to national defense. Certain areas of research-- atomic energy and cryptography -- consistently fell within its purview. But the state also placed secrecy orders on aspects of cold fusion, space technology, radar missile systems, citizens band radio voice scramblers, optical engineering and vacuum technology. Such caution, in the microbiology realm, may yield devastating results. It is not in the national interest to stunt research into biological threats.

In fact, the more likely menace comes from naturally occurring diseases. In 1918 a natural outbreak of the flu infected one-fifth of the world's population and 25 percent of the United States'. Within two years it killed more than 650,000 Americans, resulting in a 10-year drop in average lifespan. Despite constant research into emerging strains, the American Lung Association estimates that the flu and related complications kill 36,000 Americans each year. Another 5,000 die annually from food-borne pathogens -- an extraordinarily large number of which have no known cure. The science involved in responding to these diseases is incremental, meaning that small steps taken by individual laboratories around the world need to be shared for larger progress to be made.

The idea that scientific freedom strengthens national security is not new. In the early 1980s, a joint Panel on Scientific Communication and National Security concluded security by secrecywasuntenable. Its report called instead for security by accomplishment -- ensuring strength through advancing research. Ironically, one of the three major institutions participating was the National Academy of Sciences -- the body that suspended publication of the milk article earlier this month.

The government has a vested interest in creating a public conversation about ways in which our society is vulnerable to attack. Citizens are entitled to know when their milk, their water, their bridges, their hospitals lack security precautions. If discussion of these issues is censored, the state and private industry come under less pressure to alter behavior; indeed, powerful private interests may actively lobby against having to install expensive protections. And failure to act may be deadly.

Terrorists will obtain knowledge. Our best option is to blunt their efforts to exploit it. That means developing, producing and stockpiling effective vaccines. It means funding research into biosensors -- devices that detect the presence of toxic substances in the environment -- and creating more effective reporting requirements for early identification of disease outbreaks. And it means strengthening our public health system.

For better or worse, the cat is out of the bag -- something brought home to me last weekend when I visited the Tech Museum of Innovation in San Jose. One hands-on exhibit allowed children to transfer genetic material from one species to another. I watched a 4-year-old girl take a red test tube whose contents included a gene that makes certain jellyfish glow green. Using a pipette, she transferred the material to a blue test tube containing bacteria. She cooled the solution, then heated it, allowing the gene to enter the bacteria. Following instructions on a touch-screen computer, she transferred the contents to a petri dish, wrote her name on the bottom, and placed the dish in an incubator. The next day, she could log on to a Web site to view her experiment, and see her bacteria glowing a genetically modified green.

In other words, the pre-kindergartener (with a great deal of help from the museum) had conducted an experiment that echoed the Australian mousepox study. Obviously, this is not something the child could do in her basement. But just as obviously, the state of public knowledge is long past anyone's ability to censor it.

Allowing potentially harmful information to enter the public domain flies in the face of our traditional way of thinking about national security threats. But we have entered a new world. Keeping scientists from sharing information damages our ability to respond to terrorism and to natural disease, which is more likely and just as devastating. Our best hope to head off both threats may well be to stay one step ahead.

The horrifying events of 11 September 2001 serve notice that civilization will confront severe challenges in the twenty-first century. As national security budgets expand in response, we should recognize that only a broad conception of security will be adequate to meet some of the threats that we may face. Biological security provides a powerful example. It must address both the challenge of biological weapons and that of infectious disease. The right approach should benefit public health even if major acts of biological terrorism never occur. Our thinking about biological security must transcend old misplaced analogies to nuclear and chemical security.

Nuclear security has been based on nonproliferation, deterrence, and defense, with intelligence woven throughout. Nonproliferation seeks to prevent the diversion of materials from civilian programs to military or terrorist weapons. Should nonproliferation fail, the United States relies on deterrence through the threat of retaliation. Defense, active or civil, has so far been less central.

Effective biological security requires a different mix. For all its challenges, nuclear nonproliferation is comparatively robust, in part because the production of weapons-usable uranium or plutonium provides a conspicuous bottleneck through which any nuclear program must pass, unless those materials are stolen. This is why preventing nuclear theft is such a high priority in the post-Cold War world. Biological agents

are easier to acquire. Most can be found in naturally occurring outbreaks. Weaponizing these agents has proved challenging for terrorist groups, but the Aum Shinrikyo's unsuccessful efforts to spray the anthrax organism throughout Tokyo in 1993 warned that attempted mass urban attacks were no longer in the realm of the fantastic.

The transfer of dangerous biological agents should be controlled where possible, and the spread of the technologies and personnel to weaponize them should be impeded. But any biological nonproliferation regime will necessarily be less robust than its nuclear counterpart, because the relevant materials, technologies, and knowledge are far more widespread.

Biological terrorism also challenges requirements for successful deterrence. Because some diseases incubate for a week or more, identifying the perpetrators of an attack may prove difficult. A terrorist group might even hope that its attack would go unrecognized; when followers of the Bhagwan Shree Rajneesh infected 750 Oregonians with salmonella in 1984, it took over a year before the infection was determined to have been intentional. Finally, as with any form of terrorism, some groups may simply be unconcerned about retaliation.

In the face of these difficulties, good intelligence is all the more important. Warning and prevention are preferable to coping with the consequences of an attack, but we must also be ready should an attack occur. This requires that greater emphasis be placed on improving public health, a kind of homeland defense that is applicable to both unintentional and intentional disease outbreaks.

Because of disease incubation times, the first responders to a biological attack may well be health-care workers at hospitals and clinics rather than specialized units. The speed and effectiveness of a response will depend on disease surveillance: the recognition by health-care workers that certain illnesses appear unusual and the rapid notification of the proper authorities. Because incubation times often exceed international travel times, both domestic and international components are required. But the domestic component of disease surveillance in most nations, including the United States, is too weak, and international networks are inadequate. Donor nations need to increase support for these efforts. And there are many other needs, such as developing and stockpiling sufficient vaccines, antibiotics, or antivirals and otherwise preparing to meet the enormous challenges that would be posed by a major outbreak. It is time to quicken the pace of these efforts, to which departments of health are as central as departments of defense.

Disease surveillance and response are not nonproliferation measures, so cannot substitute for an effective verification regime under the Biological Weapons Convention. But biological security requires the developed world, especially the United States, to see that its ongoing self-interest is closely allied with sustainable public-health improvements in the developing world. And the explosion of biotechnology, with the weapons implications that follow from it, requires the scientific community to discuss its responsibilities in earnest.

STANFORD, Calif.- For the past seven years, the United States has been negotiating a verification protocol to the Biological Weapons Convention of 1972, hoping to put teeth into the convention's ban on biological weapons production. The Bush administration recently rejected the latest draft of the protocol, viewing it as irredeemably flawed. This is a good time to ask what a new American strategy should be for security against biological threats. It is difficult to predict the likelihood or scale of biological attack. The right policy will provide benefits whether or not an attack occurs.

The first step is conceptual: we must stop thinking about biological security in the way we think about nuclear security. Few aspects of the United States strategy for nuclear security carry over cleanly to the biological case. Security against nuclear attack has relied upon nonproliferation and deterrence, with comparatively little role, so far, for defense. Security against biological-weapons threats should lean primarily on defense.

Nonproliferation, for example, is far more difficult in the biological case. Biological agents are microscopic organisms that can be grown with equipment readily available all over the world -- although the resulting weapons have proved difficult for terrorists to master. Many of the organisms can be acquired during naturally occurring outbreaks. Controls remain valuable, but they will never play the central role that they do in nuclear security. And as biotechnology explodes in the coming decades, nonproliferation will face ever greater challenges.

Deterrence may likewise be of limited use in preventing attacks with biological weapons. While the use of battlefield biological weapons may be deterred by threats, biological terrorism could remain largely immune. The incubation times of most diseases -- for example, seven to 17 days for smallpox -- may lead terrorists to hope they can cover their tracks through covert releases of biological agents. Deterrence relies on the threat of punishment. An attacker who cannot be identified cannot be threatened.

When the Aum Shinrikyo cultists sprayed an anthrax organism in Tokyo -- they did so unsuccessfully several times before their deadly 1995 nerve-gas attack -- they made no announcements and the attacks went unnoticed. When followers of the Bhagwan Shree Rajneesh infected 750 Oregonians in 1984 with salmonella, it took over a year for the attack to be distinguished from a natural outbreak.

Rather than nonproliferation and deterrence, biological security must emphasize civil defense. Civil defense in the biological realm means improving the public health system. Most important, it requires improving disease surveillance. Unusual disease outbreaks must be recognized quickly, so that a rapid response is possible. Health care workers in clinics, hospitals and private practice must know how to identify such outbreaks and be ready and able to pass their information rapidly to city, state and national authorities.

This kind of preparedness would also help to prevent unintentional outbreaks of disease. Because infected passengers can travel the world in less time than it takes for a disease to incubate, it is crucial, for the national interest as well as for humanitarian reasons, to improve disease surveillance overseas. The United States welcomes 50 million visitors every year and imports $40 billion worth of food. Disease cannot be stopped at the border. The United States must act internationally as well as nationally.

Because biological security would offer protection against both natural and nefarious transmission of disease, a sound policy would directly benefit society even if no attack ever happened. Effective biological security requires that we fit the cure to the disease.

A biological terrorist attack probably would first be detected by doctors or other health-care workers. The speed of a response would then depend on their rapid recognition and communication that certain illnesses appeared out of the ordinary. For this reason, preparing for biological terrorism has more in common with confronting the threat of emerging infectious diseases than with preparing for chemical or nuclear attacks. Defense against bioterrorism, like protection against emerging diseases, must therefore rely on improved national and international public-health surveillance. Too often, thinking about bioterrorism has mimicked thinking about chemical terrorism, a confusion that leads to an emphasis on the wrong approaches in preparing to meet the threat.

Background: In the 1980s, many medical organizations identified the prevention of nuclear war as one of the medical profession's most important goals. An assessment of the current danger is warranted given the radically changed context of the post–Cold War era.

Methods: We reviewed the recent literature on the status of nuclear arsenals and the risk of nuclear war. We then estimated the likely medical effects of a scenario identified by leading experts as posing a serious danger: an accidental launch of nuclear weapons. We assessed possible measures to reduce the risk of such an event.

Results: U.S. and Russian nuclear-weapons systems remain on high alert. This fact, combined with the aging of Russian technical systems, has recently increased the risk of an accidental nuclear attack. As a conservative estimate, an accidental intermediate-sized launch of weapons from a single Russian submarine would result in the deaths of 6,838,000 persons from firestorms in eight U.S. cities. Millions of other people would probably be exposed to potentially lethal radiation from fallout. An agreement to remove all nuclear missiles from high-level alert status and eliminate the capability of a rapid launch would put an end to this threat.

Conclusions: The risk of an accidental nuclear attack has increased in recent years, threatening a public health disaster of unprecedented scale. Physicians and medical organizations should work actively to help build support for the policy changes that would prevent such a disaster.