Answer to Question #7517 Submitted to "Ask the Experts"

Category: Radiation Workers

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

I'm a janitor working for a medical products company. I've recently grown concerned about my work environment. I'm in charge of keeping the hallways of the biological test center clean and I'm responsible for taking out the trash. My concern is that there are several signs warning me about radiation or radioactive materials. I know a little bit about radiation but not much so I would really appreciate it if you would let me know of any possible danger that I might encounter while working there. I do not know the levels of radiation that I'm exposed to so I'm really concerned.


Thank you for your question. Although I don't know exactly what your employer uses as far as radioactive materials go, there are some general things I can share with you about a lab environment.

Regulations require postings to alert people who might enter a room or a lab that radioactive materials are present in the room. They also require that anything in the room that is radioactive be labeled as such.

So when you walk into such a posted area, take a broad look around to see what is in the lab that is radioactive. It might be that you see no labeled items—that just means the lab staff have them secured in a cupboard or in the refrigerator/freezer. Or you might see some lab equipment or samples that have a radioactive material sticker on them—that is the source of the radioactive material. As long as you do not touch or move those items, they are of no hazard to you. Most postings simply say "Caution, radioactive material." That means there is something in the room that is radioactive (and it should be labeled as such). Some postings say "Caution, radiation area." This means that if you are close to the source of radiation (which is labeled), you might receive some radiation exposure from it. You usually need to be within a couple of feet of the source to get exposed. The exposure is required to be low or nothing—otherwise you wouldn't be able to go into the area.

Kelly Classic
Certified Medical Health Physicist

Answer posted on 16 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.