Congressional lawmakers on Tuesday introduced a bill intended to reduce the threat of "dirty bombs" and radiological sabotage.

Sens. Hillary Clinton, D-N.Y., Judd Gregg, D-N.H., and Rep. Ed Markey, D-Mass., introduced the measure, which calls for better tracking of radioactive materials.

The bill would create a task force, headed by the Nuclear Regulatory Commission, to help prevent a "dirty bomb" attack in the United States.

Radioactive material that could potentially be used by terrorists would be classified and tracked by the NRC, and a national system for recovery and storage of unused material would be established.

"While the federal government has made great strides in tightening security and passing legislation to prevent bioterrorism, we are still vulnerable in counter-radiological terrorism," Gregg said.

The NRC reports that although radioactive material is lost or stolen an average 375 times per year, the recovery rate is only 60 percent. The NRC stopped tracking radioactive material by serial number in 1984.

In addition, the International Atomic Energy Agency, the same organization that conducts nuclear inspections in Iraq and North Korea, says that over 100 nations may have inadequate control and monitoring programs for radioactive material.

"Fed Ex and Lands' End have a better tracking system that the United States has in tracking radiological sources," Markey said.

Clinton pointed out that radioactive materials are widely used in hospitals, research labs, oil drilling facilities and even smoke detectors. She said the bill would help ensure proper tracking, recovery and storage of such materials and would impose more rigorous export controls.

Markey said it was no secret that terrorist groups such as Al Qaeda are trying to build "dirty bombs" or homemade nuclear weapons.

U.S. and allied troops have found documents containing nuclear information in caves in Afghanistan, and a recent report released by the British government said that Usama bin Laden's Al Qaeda network has already built a crude radiological weapon, he said.

"Despite this, and despite the recent designation to a 'Code Orange' security threat in which dirty bombs were explicitly mentioned by [Homeland Security] Secretary [Tom] Ridge," Markey said, "we have yet to do anything to improve the security of these materials."

The NRC estimates that even a small "dirty bomb" — conventional explosive stuffed or wrapped with radioactive material — could contaminate several city blocks.

Clinton said that while the U.S. government was talking about protecting the homeland from terror threats, and individuals were being told to take steps such as storing water and keeping duct tape handy, "there's been a reluctance [on the part of the administration] to establish any requirements [that might help thwart an attack]."

"Our heightened state of 'Code Orange' alert reminds us the war against terrorism continues and we must be prepared on all levels," Gregg said. "I hope our efforts will impose cradle-to-grave control of powerful radiological sources that could potentially be obtained and used by terrorists."

Markey noted that the Federation of American Scientists found that blowing up a foot-long cobalt rod would contaminate hundreds of square miles and increase the risk of death from cancer dramatically for years.

Large food and medical sterilization facilities containing millions of curies of cobalt could become dirty bombs if a large truck bomb was detonated nearby, or if conventional explosives were hidden in a shipment to one of these facilities.

Markey also took aim at U.S. Customs, pointing out that Customs agents don't screen every package entering the this country from abroad to make sure it's not leaking radiation.

"In has been 18 months since the attacks of Sept. 11, and on the eve of war with Iraq, we are probably at a higher risk of new terrorist attacks than we have been since then," Markey said. "It is time to take action to address the threat of a dirty bomb attack."

The Bush administration believes that Al Qaeda probably was in possession of often-stolen radioactive contaminants such as strontium 90 and cesium 137, which could be used to make a dirty bomb.

Fox News' Julie Asher contributed to this report.