If there were, they would have put heavy funding into hardening all of our seaports, chemical plants, nuclear facilities, and water/food supply lines. Someone could walk to the reservoir, drop a few tablets, and kill half of Boise today, there would be no resistance to speak of. Recently the FBI I believe it was, crossed our southern border with god knows how much explosives, a small nuke or some-such, I can't remember the details offhand. They met with no resistance.
Meanwhile, back at the ranch, they're planning to build 125 nuclear bombs per year. How the hell to you fight a loosely defined conglomeration of suicide bombing religious zealots, divided into small cells with nuclear bombs? You don't.
There is no war on terror. It's a ruse to enable other plans, and it's working very well. The next attack will result in martial law, as per General Tommy Franks own words.
Edited to add, it was radioactive material they brought in, enough to make two dirty bombs apparently.
http://abcnews.go.com/Politics/wireStory?id=1774664