There have been many attempts to use biological weapons. Until quite recently, they have been unsuccessful. Between 1900 and the Summer of 2001, there were 262 attempts to use bioweapons worldwide. With exception of a few Japanese biowarfare attacks on Chinese in World War II, 60 percent of these bio attacks were by terrorists and 40 percent were purely criminal (extortion, attempted murder). However, 66 percent of these 262 attacks were hoaxes, 21 were threats that never came off and only 13 percent real attacks. Of these actual attacks, 24 percent were in the United States , and resulted in no fatalities. But the 76 percent that occurred out side the United States did kill 77 people. The Japanese Aum Shinri Kyo cult made 20 attacks between April 1990 and July 1995. Half the attacks were with biological weapons (Botulinum toxin and Anthrax), but these only killed eight people. Most of the rest of the attacks used VX and Sarin nerve gas. Most of these attacks caused only a handful of injuries. But one Sarin attack, with gas released in five subway cars, killed twelve people and sent over 5,000 to the hospital (but only a fifth of these had noticeable nerve gas injuries.) 

The Aum Shinri Kyo members included many skilled engineers and scientists, graduates of Japans best universities. Aum Shinri Kyo also had plenty of money (over $300 million). Recognizing the shortcomings of their biological and chemical weapons, Aum Shinri Kyo was getting into molecular engineering when the organization was broken up by the police in 1996. Had Aum Shinri Kyo been able to keep at it for a few more years, they might have been able to develop far more deadly designer bugs that, so far, have only been produced in American and Russian military labs.

Many other terrorist organizations have tried to develop and use biological weapons. During World War I, a pro-German doctor in Washington created a supply of Anthrax and Glanders. He then used pro-German dock workers to use these two agents to infect animals being shipped to Europe for the war against Germany. This effort was not terribly successful, but it did have an effect and shows how one man, with the proper knowledge and resources, can create and employ biological weapons.

But there is a major problem, biological weapons are difficult to distribute. Yes, it's true that you can hold a quart bottle that could contain enough of some toxin to kill millions. But that's only if you can deliver to each of these people the minute amount of toxin that will kill them. This has proved to be more complex and intractable a problem than terrorists or government scientists initially realized. Moreover, the bio agents tend to be greatly weakened (or destroyed) by exposure to sun, wind or moisture. In other words, you need some very specific weather conditions for a biological weapon to spread, and the conditions you need are rare, or subject to change unexpectedly. This is what the Aum Shinri Kyo kept running into during their many unsuccessful biological weapons attacks. Even releasing bio weapons inside a buildings air conditioning system can run afoul of air filters and the like. 

Perhaps the most discouraging aspect of terrorist use of biological and chemical weapons is that your attacks are often ignored. This was the Aum Shinri Kyo experience, where many of there carefully prepared and carried out attacks were ignored, even when they caused some injuries. Locals would comment "must have been something in the air," or, "it's the weather" in the wake of the attacks. Not the stuff to be picked up by the media, even if one or two bodies were hauled away. This is the ultimate disappointment for a terrorist, not to be noticed by the media.

Aware of this problem, terrorists have been looking for solutions. The most obvious one is to obtain military grade biological and chemical weapons. Easier said than done, as little of this stuff is made any more and existing stocks are being destroyed. Moreover, most of the terrorists looking for this material are Islamic radicals who have vowed to destroy the nations that made and still possess a lot of it. This makes it very difficult for terrorists to bribe Russian or American officials to part with any of these weapons or the technology to make them. Faced with this, terrorists are trying to duplicate the government technology that has produced more lethal (and easier to distribute) biological and chemical weapons. Aum Shinri Kyo was trying to do this (by obtaining the expensive lab equipment needed) when the group was broken up in 1996. Only five years later, we have new technologies using genetic engineering that can produce even more lethal biological or chemical weapons. Moreover, the technology for genetic engineering (which promises cures for cancer and many other afflictions) is getting cheaper and easier to use. So there is a future out there that is rapidly approaching. And this future features terrorists working in labs, not furtively planting explosives or hijacking aircraft. 

In September, 2001, there was another biowarfare attack, this time using Anthrax spores sent through the mail. As a weapon, the Anthrax was remarkably ineffective. There's good reason for this. For thousands of years, Anthrax was known as a livestock pest, regularly killing animals who grazed on land infested with Anthrax spores (where the animals breathed in the spores as they pulled up grass and released the spores from the soil.) Humans could get infected as well, usually by getting spores on a cut. This skin (cutaneous) form of Anthrax was fatal in up to 20 percent of the victims, depending on how potent the Anthrax strain was and how many spores got into the sore. People who worked with sheep's wool also got cutaneous Anthrax, did those working with the hides of animals who grazed in areas containing Anthrax. In the 1970s, imported wool from an Anthrax area, improperly cleaned, infected a number of Americans. Anthrax is a bacteria, and some people and animals can fight off infections and even develop an immunity. 

Anthrax has long been pitched as an effective bio-warfare weapon. Britain developed a military form of Anthrax during World War II. At the time, it was seen as an effective weapon, because the Germans didn't have antibiotics (only the Allies had this then-new medication that easily cured Anthrax infections.) Since then, work has continued on Anthrax, developing more potent strains (so less of it was needed to kill) and making Anthrax resistant to antibiotics (difficult to do, although current genetic engineering techniques make this easier to do if you have the qualified scientists and engineers.) . The major problem with Anthrax is delivering it. The spores, in their natural form, don't travel well in the air. "Militarizing" Anthrax consists of processing the spores so they don't clump together and thus can more easily float away in a breeze. But sunlight and heat can kill the spores, and even if they float through the air, they can disperse so that anyone breathing them in will not get a fatal dose (10,000 to 50,000 spores.) Thus the need for militarized Anthrax to be grown from more powerful strains. 

Naturally occurring Anthrax (which exists in most parts of the world) varies in its potency. Wealthier nations, like the United States, give animals in Anthrax ridden areas a vaccine that protects them. There have long been vaccines for humans as well, to protect farmers and veterinarians. Agricultural researchers have collected many strains of Anthrax, and the more potent ones are kept and cultured to provide material to test new vaccines. But even the most potent militarized Anthrax isn't that powerful. We know this from an military Anthrax accident in 1979. A Russian biological warfare plant outside the city of Sverdlosk accidentally released some militarized Anthrax. Some 5,000 people were infected. But there were only 70 deaths. What was particularly discouraging to Russian military bioweapon scientists was that only one of the dead was of military age, and he was already ill from other ailments. All of those that died from the Anthrax were old, and usually sick. All the victims had weakened immune systems. Many had lung ailments. The Russians initially denied that there was an accident, and did not treat the locals for Anthrax. Later they said the deaths were caused by people eating meant infected with Anthrax (a common way for people to die from Anthrax.) It was only after the Soviet Union fell apart that Western researchers were able to get into the area and interview survivors and discover that people with normal immune systems were able to fight off an Anthrax infection. 

The 2001 Anthrax attacks in the United States used a form of natural Anthrax. There were six deaths. But more will die and get ill, but not from Anthrax. Millions of people are taking powerful antibiotics just in case they were infected. This massive use of antibiotics will cause other bacteria to become resistant to antibiotics and the resulting "super bugs" will kill a lot of people (a trend that has been noted over the last decade or so.) The problem with Anthrax as a weapon is that you have to use it in secret, and get a lot of people to breathe in the spores. While the less lethal cutaneous form announces itself with a ugly sore (which can then be treated with antibiotics), the pulmonary (breathed in) form announces itself with flu like symptoms a few days after the infection. By then, it is too late and death occurs in almost all untreated cases. With prompt treatment, the death rate is still nearly fifty percent. But if you know you have breathed it in (and a test can confirm this), you can be treated with antibiotics. So far, Anthrax has not really made the jump from livestock pest to biological warfare weapon.