Radioactivity in fertilizer

[mwilliam@mailbox.uq.oz.au (Michael Williamson)]

Does anyone know if there are US EPA regulations concerning allowable
radioactive content of fertilizers?

I recall that some fertilizers obtained from natural phosphate deposits can
have a significant U or Th content; were regulations to control such
releases ever drawn up?

If so, I would appreciate information such as the title of the regulation
and if possible, some hard numbers.

Michael Williamson                              ph +61 7 365 4504
Radiation Protection Adviser                    fax +61 7 365 1577
Occupational Health and Safety Unit
University of Queensland
Brisbane 4072
Australia