The bombings that paralyzed Paris last summer and the nerve-gas attacks in Tokyo last year are typical of the modern breed of terrorism.

There were immediate conjectures that it had been a deliberate attack, possibly linked to the nerve-gas attack last month.

The episode today and the one on Wednesday were similar to a gassing that occurred in Yokohama just days before the nerve-gas attack in the subway.

They need expensive injections of antropine, the antidote that soldiers carried in the Persian Gulf war in case of nerve-gas attacks from Iraq.

"They had a variety of different flavors to them, whether it was a building collapse," she said, "or a possible nerve-gas attack," which, for instance, would involve the Health Department.

Japanese police officers searched for leaders of the sect suspected of planning the nerve-gas attack on the Tokyo subway system last month.

Mr. Asahara is accused of ordering the nerve-gas attack on the Tokyo subway in March that killed a dozen people and injured more than 5,500.

The nerve-gas attacks would have to be scaled back now, but they would take place nevertheless.

One Brooklyn woman caught herself wondering if she should keep a wet washcloth in her purse, in case of a nerve-gas attack during her subway commute.

Aum leaders have repeatedly denied any involvement in the nerve-gas attack on March 20, which killed 12 people and injured more than 5,500.