The Utah Bureau of Radiation Control has ordered an Oregon company to stop shipping sludge containing uranium to a uranium mill in southeastern Utah.

Larry F. Anderson, director of the bureau, said Tuesday that he issued the order because of uncertainty about the type of material being moved and how it should be regulated."We want to be certain the mill is not being turned into an unlicensed waste repository," he said.

Teledyne Wah Chang Albany has shipped about 1,500 tons of sludge from its plant near Albany, Ore., to the White Mesa uranium mill in Blanding. Another 4,500 tons awaits shipment to Utah. The sludge contains small quantities of uranium to be recovered by the mill.

The operator of the Blanding mill, Umetco Minerals Corp., is the same company that wants to develop a disposal site at Uravan in southwestern Colorado for mildly radioactive materials. Utah officials, including Anderson, have been critical of the plans for the waste site.

Wallace Brice, White Mesa mill maintenance superintendent, said the company has complied with all regulations and can legally accept the sludge.

"It contains an economical ratio of uranium and will greatly enhance our chances of staying in business over a long period of time," he said.

Dale Smith, director of the Nuclear Regulatory Commission's Uranium Recovery Field Office in Denver, said he inspected the Blanding mill Thursday and found no items of non-compliance.