Vehicles transporting the following radioactive materials are exempt from the requirements in §B of this regulation: Radionuclides for medical, industrial, agricultural, or research purposes; Natural uranium metal; Depleted uranium; Magnesium-thorium alloys in formed shapes (not powdered, and which shall contain not more than 4 percent nominal thorium 232); Radium or radon sealed in needles, capsules, or similar platinum-iridium or gold containers used for medical purposes; or Manufactured articles, other than liquids, containing radioactive material as component parts, such as clock and instrument dials, electronic tubes, test instruments, watches, X-ray machines, etc. A vehicle may not enter upon any Authority property if its load includes any Class 1 explosives or any radioactive materials except under the following conditions: Prior permission shall be granted by the Administrator of the facility or the Administrator’s authorized representative at least 1 hour before intended travel over the facility; Operators of the transporting vehicles shall comply with all lawful orders, instructions, and directions of authorized Maryland Transportation Authority police personnel; Vehicles shall remain at least 300 feet behind any vehicle travelling in the same direction on the facility; Vehicles transporting Class 1 explosives shall travel at least 2,000 feet from any other vehicle transporting explosives and travelling in the same direction on the facility.