One of three JCO Co. workers exposed to massive radiation in September in the nation's worst nuclear accident died of organ failure at a Tokyo hospital late Tuesday night, becoming the first fatality of his kind in Japan. Hisashi Ouchi, 35, was critically injured during an accident Sept. 30 at the JCO uranium processing plant in the village of Tokai, Ibaraki Prefecture, where hundreds were forced to evacuate or stay indoors as an uncontrolled chain reaction spewed forth radiative particles. The amount of energy that hit him is thought to be equivalent to that at the hypocenter of the Hiroshima atomic bombing. He died at 11:21 p.m., the Science and Technology Agency said. His death, which comes 83 days after the incident, is expected to rekindle opposition to the nation's controversial nuclear power program, which has been tainted by a spate of accidents and coverup scandals in recent years. Ouchi is the second Japanese to die of acute radiation-related injuries since 1954, when U.S. fallout from thermonuclear testing in the Bikini Atolls of the Marshall Islands claimed 40-year-old Aikichi Kuboyama, who was exposed on the fishing boat Fukuryu-maru No. 5. Ouchi's body was returned to his home in Kanasago, Ibaraki Prefecture, on Wednesday afternoon, accompanied by his wife, Chizuru. Several senior JCO officials were in attendance as the casket entered the house. A statement released by Prime Minister Keizo Obuchi expressed condolences to Ouchi's family and pledged to strengthen nuclear safety measures and prevent further accidents. Tokai Mayor Tatsuo Murayama, however, portrayed Ouchi as the "victim of the safety myth" surrounding Japan's nuclear energy program, now more than 40 years old. Ouchi was part of a crew that had sidestepped safety procedures and used a bucket to pour a highly excessive amount of uranium into a processing tank, triggering a self-sustained nuclear chain reaction that neither he, his company, nor the government had thought possible at such a facility. It is suspected that their actions were accepted, if not condoned. In a matter of minutes, Ouchi had been exposed to an estimated 17 sieverts of radiation, or about 17,000 times the maximum annual permissible exposure level set by the government. The accident effectively destroyed Ouchi's immune system by sending his white blood cell count plummeting to nearly zero. As his condition worsened, the National Institute of Radiological Sciences in Chiba, Chiba Prefecture, transferred him to University of Tokyo Hospital, where he reportedly underwent the world's first transfusion of peripheral stem cells on Oct. 6 and 7. Doctors kept Ouchi alive by pumping huge amounts of blood and fluids into him on a daily basis and treating him with drugs normally unavailable in Japan, indicating the high priority the government placed on his survival, observers said. A group of top experts was assembled from Japan and abroad to treat him, with some of the sources saying they felt "silent pressure" from no particular person or body to treat his quick death as a matter of national dignity. Many who were called in to help voiced surprise that the worker had managed to hang on, despite being perhaps the only person in the world to have ever been subjected to so much radiation so quickly. But despite the urgent efforts, his overall condition did not improve, and his heart failed for about 70 minutes on Nov. 27. Doctors managed to keep him alive, but a slight recovery afterward took a turn for the worse. He had been in critical condition since Sunday, and various drugs were being used just to maintain his blood pressure and pulse at adequate levels. His unstable blood pressure was probably caused by septicemia. Despite several skin transplants, however, he continued to lose body fluids through the pores of his skin. Doctors who treated Ouchi told a news conference Wednesday that they did not take special measures such as heart massage to resuscitate him after his heart failed. They said his family had wanted his death to come peacefully. Meanwhile, Ibaraki police said they plan to step up their investigation into the criminal liability of JCO and its parent company, Sumitomo Metal Mining Co., for the accident.