Radiation leak at Japan Atomic Energy Agency facility in Ibaraki TOKYO, May 25 (UPI) -- Japan's Nuclear Regulation Authority said Saturday radioactive substances leaked into the atmosphere at a nuclear physics laboratory in Ibaraki prefecture. The leak occurred Thursday outside the controlled area at the Japan Atomic Energy Agency facility, Kyodo reported. Fifty-five researchers and others involved at the lab may have been exposed by inhaling the substances, but no one was hospitalized, the government said. The highest radiation dose measured was 1.6 millisieverts.