Democratic gubernatorial candidate Vincent Sheheen says Charleston Harbor could be put at risk if nuclear waste shipped from Germany is allowed to travel through on its way to the Savannah River Site.

"We can't allow South Carolina to become the intake and dumping ground of radioactive nuclear spheres from Germany," Sheheen said during a news conference in Charleston on Tuesday as he described the shipments of tiny, billiard-ball-size waste units under consideration.

The state and Republican Gov. Nikki Haley should do more to stand up to the federal government, he said, and not allow the waste in.

"The tremendous value of this port, of our waterways in the Lowcountry will be eliminated if South Carolina once again recklessly allows ourselves to become a dumping ground for international nuclear waste," the state senator from Camden said.

Sheheen's comments mirror press statements he made last week in which he recalled the actions of previous Democratic governor Jim Hodges, who threatened to lie down in the road to prevent trucks carrying new nuclear waste from entering SRS.

Sheheen's challenge comes as the U.S. Department of Energy is still in the public comment and feasibility study stage of the idea. It could be a year before a decision is made on whether the site near Aiken would become the holding area.

SRS spokesman Bill Taylor said the U.S. is obligated by treaty to accept the waste from German reactors, adding that removing the material to a secure site in North America would keep it from falling into the hands of terrorist groups.

The U.S. is looking at accepting some 900 kilograms of the waste units. There would be almost one million of them according to Sheheen's calculation.

If the waste is moved across South Carolina from Charleston by way of a local military port - probably by rail - it would be with high security and under sealed traveling conditions, Taylor said.

Shawn Drury, of the Conservation Voters of South Carolina, was at Sheheen's news conference. He said one fear is what happens if there is a mishap or a packaging error that affects South Carolina air or environmental quality.

"We have to consider the risks from accidents and poor oversight during the transportation of these materials," Drury said.

Haley's press office rejected Sheheen's assertions, saying Haley and her administration have demonstrated numerous instances of holding the Department of Energy accountable for cleaning up SRS.

"No one has fought harder to get the federal government to live up to their promise to remove the nuclear waste from SRS than Gov. Haley - including personally asking President Obama to remove it in 2010 and directly speaking with the Secretary of Energy four different times about the issue since then," spokesman Doug Mayer said Tuesday.

"While we certainly welcome Sen. Sheheen to this important conversation about protecting our state from federal inaction and nuclear waste, this is something the governor has been fighting to get done from the moment she stepped into office."

The Savannah River Site has about 10,000 employees. It started out as part of the government's nuclear bomb production program but has shifted roles toward nuclear cleanup.

Sheheen said although SRS is a federal facility, loud voices of opposition raised at the state level would go far in stopping South Carolina from being forced to accept the German waste.

"It's not right for South Carolina to bear that burden," he said.

Reach Schuyler Kropf at 937-5551