http://www.nytimes.com/2001/10/17/national/17WEAP.html?pagewanted=print Sign of Escalating ThreatBy STEPHEN ENGELBERG and JUDITH MILLERNews AnalysisThe discovery of what government officials say is high-grade anthraxin a letter mailed to Congress is the most worrisome development yetin a series of bioterrorist attacks that has already rattled thenation.The officials and weapons experts said yesterday that it suggestedthat somewhere, someone has access to the sort of germ weapons capableof inflicting huge casualties.So far, the officials said, the attacker or attackers have used arudimentary delivery system: the mail. Their intent and capabilitiesremain unknown, as does the amount of anthrax available to them. Butwhat worries the officials in Washington is the possibility that anadversary with even a small quantity could easily find much moreeffective means of spreading the disease.Until yesterday's preliminary analysis of the letter received by TomDaschle, the Senate majority leader, the spate of anthrax-lacedenvelopes stirred considerable anxie! ty! but posed a limited threat.Some experts assumed that the anthrax being sent around the countrywas crudely made, composed mostly of large particles that fell to theground and thus endangered primarily those in the immediate area.What government officials say arrived in Senator Daschle's office wassignificantly more threatening. Following the use of anthrax inFlorida, it suggests that for the first time in history asophisticated form of anthrax has been developed and used as a weaponin warfare or bioterrorism.The key to understanding the danger, experts said, is in the size ofthe particles. The anthrax sent to Mr. Daschle, government officialssaid, was finely milled so that it would float a considerable distanceon the smallest of air currents.Producing germs that could be spread as a mist had been the maintechnical challenge facing germ warriors throughout the 20th century.Anthrax is what the Nobel laureate Joshua Lederberg calls a"professional pathogen," a hardy germ that co! ul! d wreak havoc ifinhaled. The trick was turning it into an aerosol that lingers.Decades ago, Soviet and American scientists separately devised methodsto dry and grind anthrax into the tiny particles five microns orless that could easily enter the nostrils and lodge in the lungs.Experts say an adversary armed with anthrax in this form would have ahost of possible targets for mass terrorism. Experiments by the UnitedStates in the 1960's showed that anthrax released in the New York Citysubway could spread widely underground, infecting large numbers ofpeople. Federal officials used a benign germ related to anthrax todemonstrate the possible effects.An enemy with large quantities of high-grade anthrax could mount acredible attack on a city or large office building. Dried anthraxcould be spread using a crop-duster or small airplane equipped withthe appropriate nozzles. Buildings are an easier target and could becontaminated with a much smaller amount of anthrax pumped through a! ga! rden spray bottle, experts say.Victims of an anthrax attack can be easily treated with antibiotics,but that requires that public health officials recognize the germ hasbeen dispersed at a particular location. Experts say that detectionequipment is far from reliable, which means the first signs could comewhen people show up in the emergency room with flulike symptoms.Anthrax was one of the most important weapons in both the SovietUnion's and the United States' germ weapons arsenals.Officials from both countries say they never used germ weapons, thoughKen Alibek, a prominent defector from the Soviet germ warfare program,maintains that Moscow may have used germs as weapons against Germanyand in Afghanistan.The United States abandoned its own germ program in 1969, and soonafter most of the world's nations signed an international treatybanning the development and possession of such weapons.The Soviet Union also signed the pact, but cheated on a massive scale,say former Soviet off! ic! ials who worked to refine the strains ofanthrax, among other germs, until the fall of the Soviet Union in1990.In the 1980's, other nations, notably Iraq, began developing the germas a weapon. Iraqi scientists spent more than five years on theproject, cultivating anthrax and processing it into a wet slurry thatwas loaded into bombs and missiles.United Nations inspectors who later studied the Iraqi program saidBaghdad did not manage to produce dry anthrax that could be deliveredas an aerosol though it did buy specialized nozzles for its fleet ofcrop- dusters.In the years since, United Nations officials say, Iraq has acquiredthe capability to produce the high-grade, dry anthrax of theappropriate particle size.None of this history gives investigators much of a hint as to theorigins of the current attack. It is not clear whether the anthraxsent to Senator Daschle was produced by the attacker or attackers,bought from a foreign nation or made with the help of a roguescientist.Nor w! as! it known whether the attacker or attackers could make orobtain larger quantities.Former germ weapons scientists say that neither is easy. It tookexperienced Iraqi scientists several years to figure out how tocultivate large amounts of anthrax, which is the crucial first step tomaking a weapon.Drying the germs is relatively straightforward. But that processcreates a mix of particles that stick together, and most of them arefar too large for use as an effective weapon. Grinding the material toa small, uniform size without damaging a significant portion of thegerms is not easily done, former American and Soviet germ scientistssay.The discovery of expertly processed anthrax, one former scientistsaid, casts serious doubt on the theory advanced by some investigatorsthat the germ attacks were the work of a lone amateur with asmattering of knowledge about biology."I do think in one form or another, a state was involved," one formerAmerican scientist said. "It could be employees of ! a ! former state,such as a Russian scientist."Nor is it clear whether Al Qaeda, Osama bin Laden's network, wasinvolved in any way. American intelligence officials say Mr. bin Ladenhas tried to acquire nuclear, chemical and biological weapons.Until now, there has been no suggestion that he has succeeded in thisgoal, although there have been reports of testing chemicals and crudebiological weapons on animals at one of his training camps inAfghanistan.The attempted use of anthrax against a United States senator takesPresident Bush into a new, uncharted realm, particularly if the attackis ever linked to a specific nation. On the eve of the gulf war, hisfather weighed the question of whether to respond with nuclear weaponsto a germ attack against the United States-led coalition. After adiscussion among his senior advisers, President George Bush decidedagainst such retaliation. Instead, American officials sent Baghdad anambiguously phrased warning that was delivered in a letter from M! r.! Bush to Saddam Hussein."Your country," the letter said, "will pay a terrible price if youorder unconscionable acts."