Defense Secretary William Cohen [op-ed, July 26], who believes we should prepare for a "grave new world" of chemical and biological weapons, may be aware of facts and circumstances Milton Leitenberg is not aware of ["False Alarm," Free for All, Aug. 14]. Leitenberg seems to argue that because there have been no large, successful biological terrorist attacks in the past, there can be none in the future.

A June 13 New York Times article, "Government Report Says 3 Nations Hide Stocks of Smallpox," reported that Iraq, North Korea and Russia are assessed to be harboring undeclared stocks of smallpox virus. North Korean and Iraqi soldiers have been vaccinated against smallpox, although the disease was declared eradicated almost 20 years ago.

In 1993, North Korea was assessed by the Russians as having a smallpox weapon program. This gained a general concurrence from the CIA in an open hearing, and also is supported by defector reports. If the North Korean regime implodes, control of the virus could break down. If the local population is exposed, the virus could spread quickly to China, Japan and around the world.

Russian or Iraqi germs might find their way to the United States. Osama bin Laden has stated that it is his duty to try to acquire weapons of mass destruction. We know that he has tried for chemical and nuclear ones. He has declared war on the United States and its citizens. He has been in contact with Saddam Hussein and Iraq. He has struck in the United States before, at the World Trade Center. The chief counterterrorism organization in the United States, the FBI, has suspended giving tours of its headquarters, in part because of concern that bin Laden's supporters could strike within the United States.

The United States is ill prepared to respond to biological terrorism. There is no cure for smallpox. If a smallpox case were identified, for example, everyone who had come in contact with that person would need to be vaccinated immediately, both to protect those exposed and to prevent the spread of the virus. There are currently 15.4 million doses of vaccine in the U.S. inventory, which sounds like a lot, but Yugoslavia needed more than 18 million doses in 10 days during its bout with smallpox in 1972 -- and that was in a population of 21 million who had already been vaccinated.

The U.S. stock of vaccine is old, and some samples have failed quality-control checks. The FDA does not authorize use of the vaccine stock we do have. The vaccine often provokes reactions that must be treated with Vaccinia Immune Globulin (VIG). The U.S. stock of VIG has turned pink. It may still be effective, but the FDA does not wish to take the chance that it's not. New supplies are being contracted but will continue to be limited.

A contract is in place to provide smallpox vaccine to the military. But that vaccine is not expected to be available until approximately 2005. The Department of Health and Human Services is seeking to contract for a larger civilian supply to be available some time after the military has been vaccinated.

In 1993, the Defense Science Board stated its concern about a biological attack on the United States: "If such an attack should occur, the military establishment will be blamed for a failure in national defense, regardless of the purported mandate -- and above all, we would blame ourselves." Perhaps that is why Secretary Cohen has made increasing preparedness against weapons of mass destruction his "signature issue," as Leitenberg states. Secretary Cohen's concerns should not be dismissed, but rather should be a spur to increase preparedness.

-- David Siegrist

The writer is a research fellow at the Potomac Institute for Policy Studies.