New York, July 12 (PTI): An undercover operation conducted by Congressional investigators has revealed a major kink in the United States regulatory mechanism which could enable terrorists to easily obtain enough radioactive material to make a dirty bomb.

Armed with nothing more than a post box address in the name of a fake company, they were able to obtain a license from the Nuclear Regulatory Commission which would have allowed them to buy enough radioactive material for a dirty bomb without breaking any law.

Apparently, the regulators never conducted an investigation into whether the company actually exists and the merchandise it is carrying.

The investigators conducting a sting operation on the Commission, set up a fake construction company and sought license for Americium which is used in some construction equipment called moisture density gauges.

Daniel Hirsch, the president of the Committee to Bridge the Gap, a nuclear watchdog group, says Americium is a material very similar to plutonium and it's about 50 times more toxic than plutonium gram for gram."

Twenty-eight days later, the "company" received a license to legally buy certain quantities of Americium-241 and Cesium-137. During this period no one checked whether the company was genuine.

The dirty bomb uses conventional and radio active material but does not cause any nuclear explosion. The Commission said that it regrets that it issued the license without checking but stresses that dirty bomb is not a significant threat, according to the media reports.

Given that terrorists have expressed an interest in obtaining nuclear material, the Congress and the American people expect licensing programs for these materials to be secure," said Gregory D. Kutz, an investigator at the Government Accountability office, in testimony prepared for the hearing by the Congress.

The bomb the investigators could have built, says The New York Times, would not have caused widespread damage or even high-level contamination. But it still could have had serious consequences, particularly economic ones, in any city where it was set off.

The license, on a standard-size piece of paper, also had so few security measures incorporated into it that the investigators, using commercially available equipment, were able to modify it easily, removing a limit on the amount of radioactive material they could buy, the report says.

With that forged document, the auditors approached two industrial equipment companies to arrange to buy dozens of portable moisture density gauges, which cost about US$ 5,000 each and are used to read the density of soil and pavement when building highways, The Times said.

The machines include americium-241 and cesium-137, radioactive substances commonly used in industrial equipment.

Auditors, convinced they had enough evidence to prove their point, called off the ruse before the devices were delivered. But if they had gone ahead with the plot - which would have required extracting the radioactive materials from the machines and combining them, a job that could harm anyone in close contact - they could have built a bomb that would have contaminated an area about the length of a city block, The Times reported quoting the regulatory commission.