Naturally Occurring Radioactive Materials (NORM) and
Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) consist of materials, usually
industrial wastes or by-products enriched with
radioactive elements found in the environment, such as
uranium,
thorium and
potassium and any of their decay products, such as
radium and
radon. These natural
radioactive elements are present in very low concentrations in earth's crust and are brought to the surface through human activities such as
oil and gas exploration or
mining and through natural processes like leakage of
radon gas to the atmosphere or through dissolution in ground water. Another example of TENORM is
coal ash produced from coal burning in
power plants. If radioactivity is much higher than background level, handling TENORM may cause problems in many industries and transportation.