Highly radioactive water is leaking into the Pacific Ocean from an eight-inch crack at Japan’s crippled Fukushima Daiichi nuclear power plant, Japanese officials announced today. Radiation levels in the leaking pit are twice the legal limit, but officials stressed they’re still well below levels that are dangerous to human health. The Tokyo Electric Power Company is planning to fill the crack with concrete in order to stop the leak. The news ends the search to explain a spike in contaminated seawater measured near the plant. With contaminated water injuring workers and now seeping into the sea, some experts in the nuclear industry are questioning the decision to continue pumping Japan’s heated nuclear reactors with water in order to cool them off. [NYT, CNN, Guardian UK] Update: The first attempt to plug the crack has failed, so officials are now exploring alternatives, spokesmen for Tokyo Electric Power Co. said. Officials will try again Sunday using polymer instead of concrete.