SALT LAKE CITY - The Nuclear Regulatory Commission delayed on Monday a decision on whether to allow EnergySolutions Inc. to import the largest-ever amount of nuclear waste into the U.S., opening the window for Congress to block all foreign waste from entering the country before the decision is made.

The commission ruled that it will wait until a federal court decides whether an interstate compact can block disposal of the waste in Utah before making the decision on the company's import application.

The Salt Lake City-based company wants to bring the 20,000 tons of low-level waste from Italy through the ports of Charleston, S.C., or New Orleans for processing in Tennessee. The waste would primarily consist of contaminated metals, wood, paper, plastic, liquids and ion-exchange resins, according to the company's application.

After processing, about 1,600 tons would be disposed at the Salt Lake City-based company's dump in the western Utah desert. It is the largest and only commercially owned low-level radioactive waste dump in the country.

The proposal has drawn a record number of public comments - most in opposition to the plan.

"The NRC will defer action on the pending import license application until the dispute over the authority of the Northwest Compact is resolved or EnergySolutions outlines an alternative plan for disposal of the imported LLW (low-level waste)," the NRC order says. "In other words, an integral aspect of the Commission's determination of a facility's appropriateness for disposal of imported waste is whether the facility can actually accept that waste for disposal."

Wyoming Gov. Dave Freudenthal also opposes the plan.

In response to EnergySolutions' application, Reps. Bart Gordon, D-Tenn., and Jim Matheson, D-Utah, introduced legislation that calls for banning the importation of nuclear waste unless it originated in the U.S. or is important for the country's national defense.

The bill has stalled in committee, but Monday's ruling gives Gordon and Matheson new hope - and time. The U.S. District Court in Salt Lake City isn't expected to hear the case until the late summer or fall of 2009.

"Had NRC decided to give the green light to the importation that would have been the worst possible outcome from today's meeting," Gordon said in a statement. "By postponing their decision until this lawsuit is decided, my colleagues and I will have time to get the ban on importing foreign nuclear waste signed into law."

At issue in the federal lawsuit over whether Utah can keep the waste from coming here is the authority of the Northwest Interstate Compact on Low-level Radioactive Waste.

Utah joined the compact in 1982 under a plan by Congress to promote regional solutions for low-level waste. When EnergySolutions, then called Envirocare of Utah, sought to accept low-level waste in 1991, the state backed the company.

But at Utah's urging, the eight-state compact ruled earlier this year that EnergySolutions can only use its dump for domestic waste, not foreign waste.

However, EnergySolutions contended the compact has no authority over operations at its landfill in Tooele County, about 70 miles west of Salt Lake City, and has asked for a declaratory judgment in U.S. District Court. Utah has agreed to become a defendant in the case.

Gov. Jon Huntsman said the NRC's inaction was good for Utah.

"We've joined forces with the Northwest Compact. Together, we're a formidable team, more so than the Northwest Compact doing it on their own," Huntsman told The Associated Press on Monday. "We wanted to put the full force and credibility of the state behind this one because we feel it's important."

The company contends that the compact doesn't have authority over its Utah dump because it is a private facility and not a regional facility created by the compact. It also says the U.S. Constitution doesn't allow the compact to discriminate between domestic and foreign material handled at its Utah dump.

"We look forward to a judge making the ruling," said Jill Sigal, senior vice president of government relations for EnergySolutions.

Sigal said the company had hoped to begin importing the waste this year.

"We're not surprised by the commission's actions. We respect its (the NRC's) decision," she said. "We don't view this as a setback."

Associated Press writer Paul Foy in Salt Lake City contributed to this report.