Better Killing through Chemistry

I was reading up on nuclear proliferation when our editorial assistant came by my office. "You¿ve got a package downstairs," he said. I took the elevator to the lobby of our building, scribbled my signature on the invoice and carried my box upstairs. I then had all the material I needed to make sarin nerve gas.

Experts have been arguing for years over how realistic chemical terrorism is. Some believe it is just too hard to make and disperse deadly gases; others think we shouldn¿t underestimate terrorists¿ ability and recklessness. But everyone agrees that we shouldn¿t make it easy for them, which is why our experience is so sobering. The tightened security and heightened awareness following September 11 wasn¿t enough to stop Scientific American, just a few blocks away from Grand Central station and one floor below American Media Group (whose Palm Beach, Fla., office had just received anthrax), from acquiring the precursors of one of the world¿s most notorious chemical weapons.

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It all started when James M. Tour, a well-known organic chemist at Rice University and sometime Scientific American author, began to ring the alarm bells about chemical terrorism. While serving on a U.S. Defense Department panel to study the possibility, Tour concluded that nothing stood in the way of someone trying to acquire the ingredients of a chemical weapon. In an essay last year in Chemical & Engineering News he argued for restricting the purchase of key chemicals. "They¿re too easily available," Tour told me. "There are no checks and balances."

Unfortunately, his essay seemed to fall into the same wastebaskets as previous such warnings. One defense analyst assured Tour that the feds already monitored "every teaspoonful" of potential weapons material.

So Tour decided to do a little test. He filled out an order form for all the chemicals needed to make sarin¿the nerve agent used by the Japanese cult Aum Shinrikyo in its 1994 and 1995 attacks¿and two of its relatives, soman and GF. His secretary then placed the order with Sigma-Aldrich, one of the nation¿s most reputable chemical suppliers. If any order should have rung the alarm bells, this one should have.

Instead Tour got a big box the next day by overnight mail. By following one of the well-known recipes for sarin¿mixing dimethyl methylphosphonate, phosphorus trichloride, sodium fluoride and alcohol in the right amounts and sequence¿he could have made 280 grams of the stuff or a comparable amount of soman or GF. (That¿s more than 100 teaspoonfuls.) All this for $130.20 plus shipping and handling.

(Incidentally, some people have asked whether it is foolish to list the ingredients here. The short answer is no. For a longer answer, click here. We aren¿t telling terrorists anything they wouldn¿t already know. We are, however, telling the rest of us what we need to know if we are to prevent terrorists from acquiring these materials.)

Nor would delivering the agent be rocket science. To avoid handling poisons, terrorists could build a binary weapon, which performs the chemical reaction in situ. An off-the-shelf pesticide sprayer could then blow the miasma into a building ventilation system. Depending on how well the sprayer worked and how crowded the building was, 280 grams of sarin could kill between a few hundred and tens of thousands of people. The Aum attack on the Tokyo subway involved about 5,000 grams and left 12 people dead, but the cult didn¿t use a sprayer.

There was just one loophole in Tour¿s argument: he is an established name and could probably order just about any chemical from Sigma-Aldrich he wanted. What about the rest of us? Surely we couldn¿t just call up a supplier and buy the ingredients for sarin? Yet Tour contended that most suppliers don¿t do any screening of their buyers. "You just go to an online distributor, you give them a credit card number and it comes in the mail," he says.

And so it was. Scientific American placed our own order from a small local supply house and the materials arrived a few days later. To some extent, it wasn¿t a fair test, either, because the president of the company turned out to be a longtime reader of the magazine. But I could have been faking it.

Nerve agent experts agree that something has to be done to keep tabs on such chemicals, especially since the other difficulties of mounting a gas attack seem less daunting after September 11. Says Rudy J. Richardson of the University of Michigan, "Some of the barriers that we might have thought would be there¿like, Can terrorists disperse the agent and then escape?¿are not there. Today¿s terrorists don¿t care if they escape."

Some worry that restrictions would put an undue burden on industry, which has legitimate uses for the chemicals, and wouldn¿t stop a determined terrorist anyway. But firms already manage with controls on drug-related chemicals, and some protection would be better than no protection. "Everybody points out the ways in which a monitoring system could be bypassed, and I¿m the first to agree," Tour says. "But the thing is, right now there¿s nothing to have to bypass."

A version of this article will appear in the December 2001 issue of Scientific American. Subscribe TODAY and SAVE!