Forty years ago today, the United States and the Soviet Union signed the Biological and Toxin Weapons Convention, which banned the development, production and stockpiling of biological weapons. The treaty, which went into effect three years later, officially ended the other arms race of the 1960s, and seemed to forge the way for a world safe from the horrors of germ warfare. But 40 years later, is the danger of a bio-weapons attack any more remote than it was then? Most experts say that the opposite is true.

Dramatic advances in the life sciences have resulted in more widespread access to deadly pathogens—and to the enabling technologies that can turn those pathogens into weapons. Most biological research today is “dual use,” meaning it can be used to improve human health or to cause harm. And unlike nuclear weapons programs, biological research is easily concealed, making adherence to the 1972 treaty almost impossible to verify. The most striking example of this was the case of the former Soviet Union. While the United States destroyed all of its biological weapons prior to signing the BTWC treaty 40 years ago, the Soviets secretly maintained an illicit bio-weapons program known as Biopreparat, which employed tens of thousands of scientists at some 100 facilities. One of the most chilling projects in the program was carried out at its massive Stepnogorsk facility, which produced 300 tons of weaponized anthrax a year, more than enough to kill the entire United States population. It was only after a leading Soviet biologist, Vladimir Pasechnik, defected to the West in November 1989 that the scope and details of the program began to come out.

As many as a dozen other nations have pursued or developed offensive biological weapons programs since the treaty came into effect, U.S. officials believe, including North Korea, China, Iran and Syria. But perhaps more troubling is the fact that it has become easier for potential terrorists to obtain biological weapons. As Secretary of State Hillary Clinton said at the Biological and Toxin Weapons Convention Review Conference in Geneva last December (the seventh such international conference since the treaty was signed): “Unfortunately, the ability of terrorists and other non-state actors to develop these weapons is growing.” So, too, apparently, is their desire to do so. In 2010, for instance, al-Qaeda in the Arabian Peninsula called for “brothers with degrees in microbiology or chemistry to develop a weapon of mass destruction.” The world community remains focused on potential nuclear threats—from Iran to North Korea to Pakistan—even though a biological attack could be just as devastating, and more unpredictable.

This was the message that Ellen Tauscher, undersecretary of state for Arms Control and International Security, took to the 2009 annual meeting of the States Parties to the Biological Weapons Convention. Tauscher warned that “… a major biological weapons attack on one of the world’s major cities could cause as much death and economic and psychological damage as a nuclear attack.” Her comments came in conjunction with President Obama’s National Strategy for Countering Biological Threats, which set a platform for identifying and responding to possible bio-attacks. This new national strategy was clearly a step in the right direction, updating some of the objectives and principles of the 1972 treaty (which now has 165 signatories). But a more robust international dialogue on improving global health security—something akin to the nuclear threat dialogue—is still sorely needed.

To understand how insidiously disruptive even a small-scale biological event could be, we need only look at the anthrax attacks of September and October 2001. Several letters containing anthrax spores were mailed anonymously to news organizations and two United States senators. Five people died as a result, 17 others were infected. Congress was paralyzed and the country was on high alert for weeks—although the heightened concern was mostly transitory. The federal investigation into the attacks went on for more than eight years without an arrest. The case was finally closed in 2010, a year and a half after the FBI’s major suspect, a government bio-defense researcher named Brice Ivins, killed himself.

The potential for an “anonymous” event is one of the most frightening aspects of the increasingly complex biological threat. As new diseases emerge, as the life sciences grow more sophisticated and as globalization draws everyone closer together, there are simply more ways that a deadly virus could get loose than there were even a few years ago. It is possible that a deadly pathogen could sweep the planet and we would never know for certain if it was naturally occurring, accidental, a terror attack or something deliberately let loose by a deranged scientist—which is what the FBI believes happened with the anthrax attacks of 2001. As President Obama said recently, “We must come together to prevent and detect and fight every kind of biological danger, whether it’s a pandemic like H1N1 or a terrorist threat or a terrible disease.”

The guiding idea behind the BWTC of 1972 was that the use of biological pathogens as weapons is “repugnant to the conscience of mankind and that no effort shall be spared to minimize this risk.” The threat has grown more complicated since then. But the 40-year anniversary of the BWTC is as good a time as any to revive the spirit of that 1972 agreement and to reinvigorate the international dialogue—to make a more comprehensive and integrated effort to protect the world from the potential terror of bio-weapons.

James Lilliefors explores the issue of biological weapons research in his novel Viral, to be published today by Soho Press.