dbeeksci, you might as well forget about the Potassium Iodide, it's more of a band-aid fix in a situation that requires a tornoquet.
As the other guys said, two major hazards:
Particulate: Alpha and Beta particles, commonly called fallout. Keeping the dust and ash in a "Magic Mushroom" scenario is imperative, but very difficult depending upon the density (CPM's) and extent of the contamination. A rain suit with hood, boots and some creative use of duct tape works fine. For repiratory under 10K CPM, you need a very high efficiency filter on a full face mask, taped to your hood to form a seal. Over 10K CPM, you need Positive Pressure Full Face SCBA or supplied air, at that rate, it's so thick, it will clog a filter. In our "dirty" training room in Albuquerque, the stuff looks like talcum powder, and just fills the air from walking around in it, it's like a fog. Granted, Alpha particles can usually be just washed and brushed off. We recently have dropped the "sand scrub" technique recently in lieu of "duct tape patting", I'm not sure wich one sucks worse. The upside to sand or cornmeal scrubbing is if you are alone (or not within a CCA) you can get the vast majority of material off of yourself, the downside is that if any is left, you are just grinding it into your skin deeper. We use the tape pat because we usually have medical support handy to remove said material. Beta particles on the other hand are pretty nasty and leave some vicious "burns". They are still so hot, that they are still producing quite a large quantity of X-ray and Neutron radiation, so they are just killing cells, getting them off of you is a priority, knowing that it's there before it's too late is the hard part, Tape pat and medical are your best bet. The good part is that the stuff is so heavy that it cant usually move around, so it at least stays where it is, no breezes taking it across town like Alpha.

Transient or "Hard" radiation are another story. Gamma, Neutron, and X-Ray are all by products of nuclear material. You cant see it, smell it, or hear it. If you catch a pulse and see that "blue flash", just grab a good bottle of Scotch Whisky pull off your mask, have a seat, and relax, it won't be long. We joke about this in our teams SOP.
"The contaminated individual is required to step into a contamination collection bag and hand out all personal items for decon, then all government property for reissue, load pistol and ensure that assistant has control of the lanyard, fill out own hazardous material shipping label and hand to assistant, pull bag over head and use pistol, ensuring trajectory of bullet will not exit contamination control bag. Assistant then removes and safes pistol for decon, applies label and seals bag, repeat as necessary."
Gallows humor, gotta love it.

Seriously, if you get a good pulse, all those little pocket detectors are good for is letting you know it, because when you're bit, then you're bit, end of story. As stated, find some train tracks and look for the pretty blue train to step in front of.
The positive side is that you pretty much need a "Magic Mushroom Maker" to produce significant(fatal) ammounts of "hard" energy, not to many of those out there thank goodness. An RDD, or Radiation Dispersal Device (dirty bomb) is just a device to spread the particulate contamination around. They are more hype than most think, fairly small area, and not that much dirty material leads to news panic and only a couple hundred contaminated people. Not much in the grand scheme. Not panicking, and going through decon as soon as possible will save one nine times out of ten. If you inhaled any particulat, just be glad they have made some wonderful advances in cancer research lately.
If you want to see why you need to step in the way of that train, I have copies of the pictures from the accident in Los Alamos during the "Manhattan" project. I'll send them to you, but I won't post them, they are pretty graphic. Basically, a ball park frank in the microwave!

"The old father wove the skein of your life long ago, hide in a hole if you like, you won't live one second longer"

Have a nice day folks!

Not to minimize the danger faced by first responders here who will put their lives on the line if something like this ever occurs, but for your average Joe Citizen, I would say that the dangers of radiation from a dirty bomb, another Chernobyl type accident, etc. are very overhyped. Now, if a nuclear bomb actually detonated, that's all she wrote. And if I were a fire fighter or doing hazmat and a dirty bomb went off, then I would gear up with everything I could, including the kitchen sink, but I'm not a first responder. Just trying to give a Big Picture perspective to the discussion here. The danger of a dirty bomb is mostly psychological, not physical.

Putting aside the first question of "Well, what's the actual chance of a dirty bomb going off anywhere in the US?", then there's the question of what the damaging health effects would be? I see that you've done some reading from credible sources, like the CDC, about how experts think you should respond. And it all sounds frighteningly dangerous, but if you read medical literature that describes the actual risk involved, you'll probably be surprised that even if a dirty bomb went off right in your own city and you walked around in the stuff, on average, you're still more likely to die while driving or crossing the street or from your Happy Meal-a-day diet than from anything associated with the dirty bomb. There's plenty of credible info accesible on the web. Here's just one article on the dangers of plutonium from some of our friendly neighborhood experts over at Lawrence Livermore National Laboratory.

The 20th anniversary of the Chernobyl disaster was just a couple weeks ago. There's been an incredible amount of research into the health effects of that event, particularly in the most affected areas in Ukraine, Russia, and Belarus. And you know what? Except for a small but detectable increase in childhood thyroid cancers (the majority treatable, by the way), there's no detectable increase in cancer or leukemia above the background noise of all the other reasons people die of every year, including the usual assortment of cancers. I'm not saying that radiation doesn't cause cancer or doesn't kill or doesn't burn your skin or doesn't have any health effects--I'm saying that when taking a bird's eye look on all these millions of people who were directly and indirectly exposed to radiation from Chernobyl--some close, some farther away--there's little to see. "Only" 28 workers died from acute radiation syndrome (ARS) and about 125 diagnosed with ARS in the immediate aftermath of that disaster. And over 600,000 workers (called "liquidators") actually worked on the clean up over the years. And even among these people, the vast, vast majority of them are still going to die from the usual stuff. If you're interested in some summaries of the research done about the effects of Chernobyl, go to the International Atomic Energy Agency's website , you can find links to the IAEA's summary of the Chernobyl disaster, and a link to the WHO's 2006 report on the topic. A lot of good stuff in there.

So, in reality, sheltering in place at home or at work with the ventilation/air conditioning off for a relatively short while until the fallout settles or is dispersed will significantly reduce your already small risk of ever being negatively affected by a dirty bomb blast. Leave the lead-lined suit to Superman to protect him from kryptonite.

Very well founded post.

As emergency workers, we carry personal dosimeters in a disaster scenario. The dose limit per year is 200 millisieverts (mSv), which translates to about half a chest X-ray. For actual disasters, we've agreed on a dose of two sieverts, which (statistically speaking) causes rad poisoning in 2.something percent of healthy individuals if said radiation is absorbed within ten minutes. This is of course only if human lives are in danger. Otherwise, we foam the hell out of the area (to keep dust down), keep people away, and wait until the radiation either dies down or until the Army shows up.

Our protective suits are standard hazmat suits. They offer very little beta-, and no gamma- or neutron radiation protection, but a quick high-pressure was cleans them nicely, so you can get out of the suit in relative safety. Actual danger is minimal, the digital dosimeters have various alarm limits so we can leg it in time if we have to.

Thank you. I just hope that people understand that I'm not saying that a dirty bomb is not a danger, but just to keep it in perspective and in relation to your situation.

I was just reading from the IAEA report I mentioned. It says that on average, residents living in areas of "strict radiological control" close to Chernobyl received about 50 mSv or more in total over 20 years. (Of course, emergency workers had far higher exposures) So that's well below your annual limit of 200 mSv. In spite of this nuclear disaster that released a tremendous amount of radiation and radioactive material into the environment, the actual radiation dose over 20 years, even living near the reactor, was very minimal. Now, compare Chernobyl to the radioactive potential inside a "suitcase" dirty bomb. Danger certainly exists for emergency workers responding to a dirty bomb, but the risk for someone like me, not affected by the initial explosive blast? Like I said, the danger is more psychological than physical.

Potasium iodide has never been in the picture at any of the outages I've been to... exposure levels aren't that high. I don't know enough about it's use to answer your question, but I'd bet that it's more of a (I'll be OK, I've got these pills) last ditch/last hope type of thing to build SOME level of false security... if I"m going to die from massive cancer, I'd just as soon get it over with right now... which brings us back to the train(chuckle, snicker).

And yes, decon is the first step... clean it up so you don't spread it around.

Troy

KI pills are designed to saturate the thyroid (Iodine uptake) to avoid it taking in one of the radioacitve isotopes instead during an airborne event, that's all. No other benefit other than that; preventive.

Regards,
Bill
(former submarine officer)

'Bout what I figured, that's why they're not (common) at the big tea kettles...If things are bad enough to have to "Med Up", I'm gonna drag up <img src="/images/graemlins/shocked.gif" alt="" /> <img src="/images/graemlins/ooo.gif" alt="" /> <img src="/images/graemlins/wink.gif" alt="" />, thanks for the clarification <img src="/images/graemlins/cool.gif" alt="" />

Troy

> Now, if a nuclear bomb actually detonated, that's all she wrote.

I think that depends on how far away it is. My understanding is that there are some radiation scenarios where shelter-in-place makes sense, and where a gadget to tell you when it is safe to go outside would be useful.

Generally, the nastier the fallout the shorter its half-life, so we are probably talking about sheltering for a couple of weeks.

I tuned into the tail end of 20/20 last night and John Stossel's segment caught my attention because he was talking about the ultimate health impact of Chernobyl (I think he refers to the same IAEA report that I did in an earlier post). Overall, the 20/20 segment's topic was the "myth" that radiation is bad for you (20/20's choice of words, not mine). A webcast of that segment isn't available, but the transcript can be read here. Anyway, just more food for thought.