July 16, 1979, Church Rock, New Mexico, accidental release of radioactive mine tailings

September 29, 1979 - Tritium leak at American Atomics in Tucson, Arizona at the public school across the street from the plant. $300,000 worth of food was found to be contaminated; the chocolate cake had 56 nCi/L (2,100 Bq/L). By contrast, the EPA safety limit for drinking water is 20 nCi/L (740 Bq/L) based on consumption of two liters per day.

https://en.wikipedia.org/wiki/List_of_civilian_nuclear_accidents

https://www.wikiwand.com/en/List_of_civilian_radiation_accidents