On February 1st of 1996 four kittens (about 3 weeks old) were found in Unit 1 of the heavily guarded San Onofre reactor near San Diego. Initially, these kittens had a reading of 6000 counts/min. After a shampoo bath this was reduced to 1000 counts/min. Cesium-137 accounts for 98% of the counts with Cesium-134 and Cobalt-60 accounting for the other 2%. The day before, an adult female cat became contaminated from contact with dirty areas in of the defunct reactor in Unit 1 that were exposed to the environment. This cat was taken to the other side of the Interstate 5 and released. Unfortunately, it is believed that she died (remains of a slightly radioactive adult female cat were found). Once the level of radioactivity in the kittens dropped to acceptable levels they were given up for adoption. The names of the kittens are Alpha, Beta, Gamma and Neutron.


http://facilities.uchicago.edu/organization/radiation/uofcinfo/Newsletters/DECEMB~1.HTM
http://www.vanderbilt.edu/radsafe/9602/msg00249.html