THE HIDDEN DANGER OF MANTLE LAMPS

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

The Physicist further advises that the initial preburning, and all subsequent lighting, of mantles be performed in an open area with adequate air circulation . . . and that only after 15 to 20 minutes of burning should a mantle lamp be brought into a closed environment. What's more, Wagner notes that the thorium is in place even after the mantle has been burning. You see, one of the reasons manufacturers use thorium is that it has a very high melting point. Therefore, a mantle will continue to emit alpha radiation during use, with most of these particles being stopped by the glass chimney. On the other hand, once the mantle is lighted, most of the radium will boil off in the first 15 to 20 minutes, and the mantle won't emit further beta radiation until several days later . . . when Ra-224 is produced by the decaying thorium.

Wagner suggests that if you light your lamp once a day, it should be vented to the outdoors. If the lantern is used continuously, however, venting is probably not necessary, as the air change in the room should be adequate.

Users of mantle lamps should especially avoid breathing in the particulate ash or getting any ash in their food. ("Thorium ash is very bad to inhale," Walter says, "as it simply sits in the lungs for months to years, and when it eventually gets into the blood, it goes directly to the bone, where—again—it stays for years.")

It's impossible, of course, to avoid some exposure while changing the mantles . . . however, since that procedure normally requires only a few minutes, the total risk is small (less than one chance in a million of a resulting cancer). By contrast, leaving a mantle in a pocket for hours at a time increases the risk of cancer considerably (up to one chance in 10,000).

When it comes time to dispose of a mantle, Wagner suggests that the ashes not be deposited on a compost heap or tilled into garden soil, where the radiotoxicity could become part of the food chain. Rather, it's better to put the old mantle with trash that will be going to a landfill or other dump.

Given all the facts, why haven't mantle manufacturers admitted the hazard of thorium? That's a question Walt hopes to have answered when the suit comes to trial. (Following two postponements, a hearing is scheduled— as of this writing—for September or October of this year.) Coleman has called Wagner's allegations "preposterous" and charged that his conclusions are more "emotional than scientific".

RSS | Comments | E-mail | Print