Iran's growing industrial and medical capabilities could enable the country to produce chemical or biological weapons if it chose to do so, security expert Anthony Cordesman said in two draft reports released this month.

Drugs intended to be used as nonlethal weapons are almost certain to kill people if used during a crisis, the British Medical Association said in a recent report.

Chemical weapons have been an international taboo for decades. But now, some in the United States Air Force are pushing to use them again. A recent study out of the Air War College calls for using chemicals as "first-use weapons against terrorists" -- part of a larger pitch to rethink the long-time pariah of military warfare.

An in-depth look at that claim that Iraqi insurgents might be using a military-grade hallucinogen on themselves to artificially increase their agressiveness.

Many experts believe the odds for a chemical attack are relatively high, compared with biological or nuclear terrorism because of the widespread availability of raw materials including millions of military-grade chemical weapons scattered in at least a dozen countries.

They were no-shows in Iraq, but tons of chemical weapons are stoking fears and costing billions to clean up elsewhere in the world - from concrete "igloos" in Oregon, to the Panama rainforest, to the highlands of China, where Japanese war leftovers reportedly have killed hundreds.

The US Defense Science Board, a senior advisory body to the Pentagon, has recommended exploration of the use of calmatives as strategic weapons. Calmatives, such as anesthetic or psychoactive drugs, are the same type of weapon was that tragically used at the end of the Moscow Theater siege in October 2002.

Over the past year harrowing first-hand testimonies from North Korean defectors have detailed execution and torture, and now chilling evidence has emerged that the walls of Camp 22 hide an even more evil secret: gas chambers where horrific chemical experiments are conducted on human beings.

Senior U.S. military officials and independent experts are concerned North Korea would use chemical or biological weapons tactically to devastate U.S. and South Korean forces in the event of war, potentially producing a dilemma of U.S. retreat or nuclear retaliation.

North Korea?s weapons of mass destruction remain the subject of speculation, guesswork and rough estimates, but the secretive nation has probably developed both nuclear and chemical weapons, according to a panel of experts who spoke at a recent forum.