Monitors have been installed around the city to measure for airborne radiological, chemical or biological substances.

Contaminants are any physical, chemical, biological or radiological substances or matter in water.

The final "topic area" is devoted to technology to "monitor, detect and characterize purposely concealed chemical, biological, radiological, nuclear . . . and high-explosive substances," and to neutralize them: Develop methods to determine if terrorists have worked with weapons of mass destruction.

City officials said they were putting more police officers on patrol at landmarks and important sites, establishing checkpoints at bridges and tunnels, and calling in teams of National Guard members who are trained to detect chemical, biological and radiological substances.

Officials were reluctant to discuss terrorism precautions in great detail, but they said that the city regularly monitors the air with machines that can detect the presence of chemical, biological or radiological substances.

Ms. Fernandez plans to work for a few years in nuclear medicine, which involves injecting patients with radiological substances for diagnostic imaging.

But even if loyalty and alliance hold between Washington and its Persian Gulf friends, who can say what the effect would be if Saddam Hussein fired Scud missiles loaded with anthrax, mustard gas or some ghastly radiological substance onto the main Saudi oil loading terminal at Ras Tanura, causing panic and shutdown?