Here's what the link to Sing Outs! songfinder comes up with:
"Ann and Marry Cleary's STRONTIUM 90, our intrepid Editor, Mark Moss, blasted back with the following: "There were two recordings of the song that I know of ... both from the early 1960s: Inman and Ira, Singing Spokesmen from the New Generation, Mercury #20778, LP (196?), cut#A.06; and Johnson Boys, Singin' and Pickin', Bethlehem #4013, LP (1963), cut#A.01 (Strontium Ninety)."
Unfortunately no lyrics but I think they are in the Sierra Club Environmental Songbook that is buried somewhere in my livingroom; I might be able to access that book after the spring thaw!