Authorities in Western Australia are searching for a dangerously radioactive capsule, which they believe fell off a truck while being transported. But they have a problem: The capsule is smaller than a penny, while the search zone is a stretch of vast desert highway about as long as California’s coastline. The capsule, a silver cylinder measuring 0.3 inches by 0.2 inches, came from a Rio Tinto mine and formed a part of a sensor used in mining. The sensor had been put onto a truck and driven from the mine, near Newman in the remote north of Western Australia, to Perth, the state’s capital, on a trip that took several days. The capsule, which contains a small amount of cesium-137, is dangerously radioactive, according to authorities. An hour of exposure at about a meter (about 3 feet) away is the equivalent of having 10 X-rays, and prolonged contact can cause skin burns, acute radiation sickness and cancer, they said. The truck carrying the sensor arrived in Perth on Jan. 16. On Friday, nearly two weeks later, authorities called an emergency news conference to alert the public that the capsule had disappeared along the 1,400-kilometer (870-mile) journey. “We want the public to be alert to the possibility of finding the small capsule and the risks,” David Gill, a chief superintendent for the Western Australia emergency services department, said Friday. The state’s chief health officer, Dr. Andrew Robertson, warned the public to stay at least 5 meters away from the capsule if they spot it. According to authorities, the sensor containing the capsule was placed inside a wooden box, which was screwed onto a pallet and placed in the back of a flatbed truck. They believe that vibrations from the truck caused the sensor to shake apart and also dislodged a mounting bolt, leaving a hole in the bottom of the box. The capsule is believed to have fallen out of the sensor, through the bolt-hole, onto the surface of the truck, and bounced off into the road. Although the truck made the journey from Jan. 12 to Jan. 16, the capsule was not discovered to be missing until Wednesday. Police believe the disappearance was an accident, and there is no evidence that the box was tampered with after arriving in Perth, Robertson said.
