MICHELE NORRIS, host:
Health physicists say this is the first case they can think of in which polonium was used as a poison.
We asked NPR's Richard Harris to find out a bit more about Polonium 210. The assignment sent him down the block from NPR headquarters.
RICHARD HARRIS: Polonium is actually a naturally occurring element. You can find it in trace quantities in the soil, you can find miniscule amounts of it in seafood and if you know where to look, you can find it in consumer products.
I'm at a camera shop in downtown Washington, D.C.
Hi, I'm Richard Harris from National Public Radio.
Mr. BOB GITOWSKI(ph): Bob Gitowski, Pen Camera.
HARRIS: Nice to meet you. Do you have anti-static brushes perchance?
Mr. GITOWSKI: Yes, we do.
HARRIS: Could I see one?
Mr. GITOWSKI: Certainly. They're right over this way. This is the brush itself. It does use a static charge to remove the items that are clinging to the negatives.
HARRIS: Do you know where the static charge comes from?
Mr. GITOWSKI: It comes from a cartridge that is inside the brush here, and I'm going to mispronounce, Polonium 210?
HARRIS: That's right. Recently an infamous ingredient, I guess.
Mr. GITOWSKI: I have heard that, yes. But it actually does the work.
HARRIS: It actually does the job?
Mr. GITOWSKI: It does an excellent job, yes.
HARRIS: Of course if you want enough polonium to do real damage, you wouldn't buy a brush. You'd probably find some way to get it from a nuclear reactor where it is made for anti-static brushes and related products used industrially. And it doesn't take much to do harm.
Mr. ANDREW KARIM(ph) (MJW Corporation): It's actually one of the nastier radioisotopes that we have.
HARRIS: Andrew Karim is a certified health physicist in New York State at MJW Corporation.
Mr. KARIM: It's got a fairly high energy radiation that it gives off so it does not take very much of it to really hurt somebody.
HARRIS: It doesn't take much at all to make a lethal dose.
Mr. KARIM: We're probably looking at a couple of grains of salt.
HARRIS: So what's it doing in a commercially available anti-static brush? Easy. It's actually quite harmless unless you ingest it. That's because the radiation it emits is in the form of big, slow moving particles. It's called alpha radiation.
Mr. KARIM: As long as the alpha radioactivity stays on the outside of you, you don't get any radiation dose at all. We're all surrounded by a layer of dead skin cells a couple layers thick. That's what peels off, for example, when you get sunburned. And that thickness of skin cells is enough to completely shield you against alpha radioactivity.
HARRIS: Karim says you can safely carry it around in a sealed jar, for instance, and no radiation will get out.
Kelly Classic, a health physicist at the Mayo Clinic, speaks for the Health Physics Society. She says the trouble begins with these alpha particles get inside you through air, food or a puncture wound.
Dr. KELLY CLASSIC (Health Physics Society): Well when they get inside the body and they get into critical tissues, all of their energy is deposited in that very, very small area. So they deliver a very high dose to a very small area and if that's a critical organ, they can shut that organ system down.
HARRIS: That's apparently what happened to Alexander Litvinenko. But that's also why health officials are apparently not too worried about people who may have come in contact with this material in most of the areas where traces of Polonium 210 have been found. Again, Kelly Classic.
Dr. CLASSIC: If I were on one of those planes, I personally wouldn't be concerned simply because unless I would have taken microgram amounts of this material into my mouth or inhaled it, it's not going to be a health hazard for me.
HARRIS: Health physicist Andrew Karim says he also wouldn't be worried about being on those flights. He says passengers almost certainly got more radiation exposure on the planes simply from being up in the air and exposed to more cosmic rays.
Richard Harris, NPR News.