The Tri-City Herald reported Friday that the Washington Department of Health took the action late last month against Energy Northwest.
State officials say the utility on July 20 sent a mislabeled shipment of radioactive waste to the Hanford nuclear reservation in southeastern Washington.
Energy Northwest spokesman Mike Paoli says the mislabeling was minor and did not endanger public health or safety.
Paoli says the state health department acted correctly, but the shipment itself was properly packaged and accepted for storage at the Hanford site.
He says the no-shipping order means material will be stored at the Columbia Generating Station while officials review shipping procedures.