Answer to Question #11448 Submitted to "Ask the Experts"

Category: Nuclear Power, Devices, and Accidents — Nuclear Devices

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


My question is about the effects of the U.S. nuclear tests in Nevada. I read that testing stopped in 1992, but since then subcritical tests have been performed in the area. Could the fallout products from subcritical tests be carried on the wind to nearby cities like Las Vegas? I am asking because my solid carbon water filter (which I've been using since 2011) is made and assembled in Las Vegas, Nevada. Could radioactive particles from subcritical nuclear tests be absorbed into things like my water filter that's made in Las Vegas?


In the subcritical testing since 1992, there has been no nuclear chain reaction (the reactions did not go critical). Because there was no chain reaction, no radioactive fallout was created. The Nevada testing area is under strict controls, and ambient radioactivity levels are carefully monitored. Monitoring data are available online at

It should be noted that trace amounts of naturally occurring radioactive materials from rocks and soils are ubiquitous, and they can be found in air, food, and water everywhere. Those radioactive particles, along with any residual fallout from past atmospheric weapons testing, are considered part of "background" radiation. Your water filter is designed to remove various particles from your drinking water, including background radioactive particles. But don't worry about your filter becoming radioactive from the few particles that are removed—background radiation is not a health problem. The fact that your filter is manufactured in Las Vegas should not be an issue.

Joel I. Cehn, CHP
Phil Egidi

Answer posted on 25 February 2016. 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.