"That's a lot of waste," said Arjun Makhijani, executive director of the Institute for Energy and Environmental Research, a nuclear watchdog group. "As far as I know, it's unprecedented for such a large amount to come to this country for disposal."

In a statement Tuesday, EnergySolutions argued that licenses had been grantedto companies that import radioactive items from France and the Czech Republic. The company also said it is a leader in safe handling and disposal of radioactive materials.

However, two congressmen wrote in a letter to federal regulators who will ultimately decide if the material can be shipped to the U.S. that EnergySolutions had not said exactly where the waste would come from, other than "reactors, fuel cycle facilities, research facilities, and material licenses or facilities equivalent to U.S. Superfund sites."

Limits may be exceeded

Reps. Joe Barton, R-Texas, and Ed Whitfield, R-Kentucky, also argued that some of the waste could exceed federal radiation limits, meaning it would not be allowed to enter the country and would have to be shipped back to Italy.

Nuclear Regulatory Commission spokesman David McIntyre said the agency will begin taking public comments on EnergySolutions' application soon. The approval process typically takes six months.

EnergySolutions, which handles radioactive waste for hospitals, universities and companies, has operated a nuclear waste landfill site in South Carolina since 1971. But under legislation passed earlier this year, that landfill will close to all but three states next year — South Carolina, New Jersey and Connecticut. If EnergySolutions gets approval, it's not clear where the materials would be unloaded in Charleston.

"We don't handle any radioactive materials," said Byron Miller, spokesman for the State Ports Authority.