A truck that plunged into a central North Island stream this morning was not carrying any radioactive substances, according to the Fire Service, but its driver is still missing. Radiation fears were sparked after the fully-laden B-train truck, marked with a radioactive materials sign, was found in the Waihohonu Stream on State Highway 1 between Waiouru and Turangi. Emergency services were called to the scene outside the Tongariro National Park boundary at 4.22am.