Answer to Question #7501 Submitted to "Ask the Experts"

Category: Environmental and Background Radiation — Chemical Elements and Compounds

The following question was answered by an expert in the appropriate field:


We have a researcher who would like to use samarium powder in a chemistry catalyst experiment. The MSDS (material safety data sheets) for the samarium powder lists it as radioactive. However when talking to the manufacturer they could not tell me the radionuclide type or the activity. From the company: "Our samarium products are shipped as 'radioactive' according to the department of transportation simply because they are extracted from natural ore materials and will have a certain level of radioisotopes present. However, the material is not considered radioactive according to Occupational Safety and Health Administration or the Nuclear Regulatory Commission. Unfortunately, we do not measure the radioactivity, so we don't have an exact value."

I was hoping for some advice as to how to  handle exposure issues and the generated waste.


Thank you for your question pertaining to the use of samarium and its associated radioactive material concerns. As your question correctly indicates, samarium is a rare earth element that is extracted from natural ore materials such as mineral monazite and bastnasite. As such, the use of this material MAY require a radioactive materials license. It is recommended that you contact your state radiation protection program for guidance in this matter.

Specifically, the samarium powder may be associated with sufficient concentrations of source material (e.g., uranium and thorium) that can result in having a licensable radioactive quantity. The following regulation was obtained from the Conference of Radiation Control Program Directors (CRCPD) Web site:

Sec.C.3,a. "Any person is exempt from this Part to the extent that such person receives, possesses, uses, owns, or transfers source material in any chemical mixture, compound, solution, or alloy in which the source material is by weight less than 1/20 of 1 percent (0.05 percent) of the mixture, compound, solution, or alloy. b. Any person is exempt from this Part to the extent that such person receives, possesses, uses, or transfers unrefined and unprocessed ore containing source material; provided that, except as authorized in a specific license, such person shall not refine or process such ore."

As indicated in the above language, the key is whether the associated natural ore has a source material concentration less than 1/20 of 1 percent (0.05 percent). Again, your state radiation protection program will be able to provide much more detailed support in this matter.

Eric W. Abelquist, CHP

Answer posted on 12 May 2008. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.