NORM (Naturally Occurring Radioactive Material) is found in many naturally-occurring materials, including some oil and gas deposits.
Sources of NORM include:
- Uranium;
- Thorium;
- Radium; and
- Lead-210
When NORM is transported to the surface in production streams it can precipitate and accumulate inside tubing strings, surface equipment and piping as sulfate and carbonate deposits. NORM can also be found in refinery piping. It has been estimated that, every year, the US oil and gas industry produces roughly 260,000 tonnes of NORM contaminated sludge and scale, and around 18 billion barrels of contaminated waste fluid. NORM-contaminated materials typically contain uranium, thorium, lead and radon, and their respective decay elements ('progenys'). These materials present a risk to workers due to direct gamma radiation exposure and airborne radioactive dust inhalation.