The largest radiation spill in US history was at Church Rock, NM on July 16, 1979.  1ooo tons of solid radioactive waste and 93 million gallons of acidic radioactive solution broke through an earthen dam and flooded 80 milles of the Puerco River from Gallop NM to Navajo County, Arizona.  Navajo Indians requested, but NM Governor Bruce Kind refused to declare a national disaster emergency. In 1983, the United Nuclear Corp site was declared a superfund site; since then the cost of cleaning the 250 acre site has been $250 million. In 2014, the EPA recommended Navajo Indians living on contaminated lands along the Puerco River leave their contaminated homes.