Plans to dump more than a million tons of contaminated water from Japan’s Fukushima nuclear power plant disaster into the ocean are being highly criticized. Greenpeace warns in a report that the water stored after the 2011 meltdowns at the facility has such high levels of the isotope carbon-14 that it could damage human DNA if released into the Pacific. The move has also been strongly opposed by local fishermen. The Greenpeace report says that carbon-14 has a half-life of 5,370 years and would become “incorporated into all living matter” over time if released into the wild. But Japan’s Prime Minister Yoshihide Suga says the dumping can’t be postponed forever.