The amount of radiation that has seeped into the Pacific Ocean from Japan’s damaged Fukushima-Daiichi nuclear reactors is more than three times higher the original estimate conducted by Tepco, the company that owns the power plant. Takyua Kobayashi of the Japan Atomic Energy Agency said on Friday that the faulty estimate was likely the result of Tepco’s failure to measure the airborne radiation that landed at sea. Researchers found that, contrary to Tepco’s estimate of 4,720 trillion becquerels of cesium-137 and iodine-131, more than 15,000 trillion becquerels was released into the ocean between March 21 and April 30. On top of that, the researchers didn’t measure the presence of cesium-134, meaning that the true amount of radiation in the Pacific is higher still. In the aftermath of the nuclear meltdown caused by an earthquake and tsunami earlier this year, radiation has been found in seafood and seaweed off the coast of Japan. Tepco hopes to have the reactors in a state of cold shutdown by January.