French officials barred residents in three towns from using two rivers in southern France after waste containing uranium leaked into the waterways.
The accident happened at the Tricastin nuclear site at Bollene, about 25 miles from Avignon, the BBC reported. Residents along the Gaffiere and Lauzon rivers were banned from fishing, using water from wells, swimming in the rivers or using river water for crops.
The unenriched uranium was toxic but the French nuclear safety agency said the risk to humans was slight.
Uranium concentrations in the Gaffiere River initially were about 1,000 times higher than normal but were falling, spokeswoman Evangelia Petit said.
About 7,925 gallons of solution containing the uranium spilled from an overflowing reservoir at the site into the ground and the rivers, the British broadcaster said.
Abandon Nuclear Power, an anti-nuclear group, said it thought authorities were downplaying the danger posed by the waste.
It is impossible that such a spill, containing uranium, does not have important consequences for the environment and for health, the group said in a statement.
About 80 percent of France’s electricity is from nuclear power.