So ... oil drilling creates radioactive waste? Interesting.

[eppur_se_muova]

Radium-bearing barite (radiobarite) is a common constituent of scale and sludge deposits that form in oil-field production equipment. The barite forms as a precipitate from radium-bearing, saline formation water that is pumped to the surface along with oil. Radioactivity levels in some oil-field equipment and in soils contaminated by scale and sludge can be sufficiently high to pose a potential health threat.
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Barium sulfate (barite) is one of the more common minerals that occur as coatings or sediments in oil-field production equipment (Wilson, 1994). Precipitates of barite form when saline formation water (produced water) is pumped to the surface with oil and is then separated from the oil and disposed of, most commonly via an injection well. Produced water can become oversaturated with barite in response to decreases in solution temperature, pressure, or salinity ( Blount, 1977).

As early as the 1930s it was recognized that some of these barite precipitates are unusually radioactive (Kolb and Wojcik, 1985). The ionizing radiation originating from barite is derived from radioactive decay of naturally occurring radium isotopes (226Ra and 228Ra) and their decay products (Kolb and Wojcik, 1985). Radium and barium are chemically similar alkaline-earth elements and dissolved radium is efficiently sequestered by barium sulfate precipitates ( Doerner and Hoskins, 1925). Oil-field brines, particularly chloride-rich varieties, can contain tens to thousands of picocuries per liter (pCi/l) of dissolved 226Ra (Fisher, 1998). For comparison, the US drinking water standard for total dissolved radium (226Ra+228Ra) is 5 pCi/l (Federal Register, 1976. National Interim Primary Drinking Water Regulations. 41 CFR, Part 132, 28404, July 9, 1976.Federal Register, 1976). Barite scale and barite-bearing sludge can likewise contain tens to thousands of picocuries per gram (pCi/g) of radium ( Wascom, 1994), compared to typical soil values of 0.5–5.0 pCi/g ( American Petroleum Institute, 1992).

Concerns about the possible health risks of radioactivity in the US oil industry were raised to a higher level in the 1980s, as industry and regulators realized that the problems were more widespread than originally thought and that some radioactivity levels could be quite high. Radioactive oil-field equipment, and radium-bearing scale and sludge from oil-field operations are varieties of a special type of waste designated as ‘naturally occurring radioactive material’ (NORM). At present (1999) there are no federal regulations in the United States that specifically address the handling or disposal of NORM from oil-field production. Several States with significant amounts of oil production have implemented their own regulations for oil-field NORM (NORM Report, 1996). The magnitude of the oil-field NORM problem in the United States has been estimated ( Otto, 1989), but it remains to be completely assessed.

Assessment of radioactive contamination at oil-field production sites typically requires detailed radiation surveys of equipment and contaminated soil, and measurements of radium isotopic abundance in selected soil samples. Clean-up costs are largely determined by the volume of material that exceeds State regulatory thresholds for radioactivity of equipment or for total radium concentration of soil. Individual States have enacted or are considering regulations that allow as little as 5 pCi/g or as much as 30 pCi/g of radium in the upper 15 cm of soil (NORM Report, 1996). Surface radioactivity of oil-field equipment is typically limited to some low multiple of local background values.
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more: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VB5-42YW1SJ-7&_user=558534&_coverDate=08%2F31%2F2001&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1350809123&_rerunOrigin=google&_acct=C000028489&_version=1&_urlVersion=0&_userid=558534&md5=cb0c0d0e294c2aaefccbb25cd4357544