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Phosphogypsum
Fertilizer is added to soil to improve the quality or quantity of plant growth. Natural fertilizer is composed
primarily of manure. While man-made fertilizer contains the same main components of manure, man-made
fertilizer ingredients are always consistent and are formulated to produce the best results from plants. One of
these components, phosphorous, is inserted into the man-made fertilizer through a process that leaves behind a
radioactive waste called phosphogypsum.
Phosphate ore - the source for phosphorous - is recovered by open pit mining. The rock is transported to a
washing facility, separated from accompanying soil, and processed. To get the phosphorous into a water-
soluble form that the plants will absorb, the phosphate is converted into phosphoric acid. Phosphogypsum,
the byproduct from this conversion, contains uranium and radium. The radium is of particular concern
because it decays to form radon, a cancer-causing, radioactive gas.
Phosphogypsum is virtually useless, and is disposed of in large, above-ground stacks, or piles. A total of 63
phosphogypsum stacks were identified nationwide in 1989, in 12 different states. Two-thirds of these stacks
were located in Florida, Texas, Illinois, and Louisiana. In Central Florida, one of the major phosphoric acid
producing areas, the industry generates about 32 million metric tons of phosphogypsum each year, which
equals the combined weight of approximately 6.4 million elephants.
Who is protecting you
U.S. Environmental Protection Agency (EPA)
EPA has regulated phosphogypsum since 1989 and has banned all use of the material, except for
phosphogypsum with extremely low radionuclide concentrations. EPA requires phosphogypsum to be placed
in large piles or "stacks" to prevent it from entering the environment.
The States
Through partnering with EPA, some states have placed restrictions on the management of this material. The
State of Florida, for example, has regulations in effect that require proper management and closure of the
phosphogypsum stacks in the state. There are also State efforts to minimize the amount of waste generated in
the phosphoric acid process, meaning less phosphogypsum generated.
What can you do to protect yourself
Phosphogypsum stacks pose little risk to people because they are highly regulated to prevent unnecessary
exposure to the public. The stacks are kept on private property, away from the general public, and workers
are required to follow specific radiation safety procedures at the stacks and the phosphate fertilizer plants.
Resources
You can explore this radiation source further through the resources at the following URL:
http://www.epa.gov/radtown/phosphogypsum.htmltfresources
We provide these resources on-line rather than here so we can keep the links up-to-date.
United States Environmental Protection Agency
Office of Radiation and Indoor Air (6608J) | EPA 402-F-06-015
April 2006
www.epa.gov/radtown/phosphogypsum.html
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