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15 March 2010

Answer to Question #6125 Submitted to "Ask the Experts"

Category: Consumer Products — Watches, Clocks, and other Glow-in-the-Dark

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

I have inherited an office desk with a fluorescent tube (not compact fluorescent, but an actual tube) light fixture mounted underneath it. The desk is from 1990.

Recently I read that some fluorescent lights use a radioactive material as a "starter." Is this the case for fluorescent tubes? The ballast unit appears to be in the housing and I don't see any little "canister" in contact with the fluorescent. Is the radioactive "glow tube" starter up in the ballast unit? Or would it be obvious? I'm curious about this since it is in my home and want to make sure it is not hazardous (other than the mercury vapor in the tube!).

Part of the answer to your question, regarding the risk, is covered in ATE Question 5304. I have done a search to see what I could find about fluorescent lights containing radioactive materials and have not been able to find much. But I learned enough to feel comfortable making a few comments that should help out.

First, no matter what the product is, there are limits to the amount of radioactive materials that can be put into anything that can be sold to a member of the general public. The bottom line is that nobody is going to be permitted to buy something at the store if it contains a potentially hazardous amount of radioactivity. To do that, you have to apply for a radioactive materials license. So, the fact that you can buy these light bulbs—compact or linear—at the store rules out any sort of health risk from whatever amount of radioactive materials might be inside of them. In fact, the mercury vapor is probably more dangerous than whatever amount of radioactivity might be inside.

Second, I have only found information on radioactivity inside of the compact fluorescent lights. I even checked in our home, and none of our fluorescent bulbs are listed as containing radioactivity except for the packages for the compact bulbs. Finally, referring to ATE Question 5304, the exact amount of ¹⁴⁷Pm inside the compact fluorescent lights is much smaller than the amount in a watch dial. Given that the watch dials are also going to contain a safe amount of ¹⁴⁷Pm, we can be even more confident that the lights do not contain a dangerous amount of radioactivity.

So I think there are several lines of evidence suggesting that fluorescent lights don't contain enough radioactivity to be a danger to you or to your family. Just don't eat them and watch out for the mercury, and you'll be okay!

P. Andrew Karam, PhD, CHP

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