One less reason to wet the bed
According to a new study, dirty bombs are highly unlikely to disperse significant amounts of radioactive dust over long distances. They did tests with conventional explosives and non-radioactive dust mimicking common radioactive materials, and found that most of the dust did not travel long distances. This means that relatively few people will be hurt by a dirty bomb, and that a relatively small area will be affected.
The article doesn’t make it clear how small the distance was, but apparently it was smaller than many previous estimates.
Although I must withhold a final technical judgement until I see the numbers and methods, I’m not terribly surprised that experiments would find less dispersal than most fear. In grad school I spent some time doing experiments with ceramic powders, and making really small particles is really hard. The small ones tend to stick together, and it’s the small ones that you need to get wide dispersal.
Not to mention that the wider the dispersal radius, the more radioactive material you need. Think about it: If you spread it out, you’re just reducing the dose of radiation that each person exposed can receive. If you concentrate it, you reduce the number of potential victims and the amount of property that you can put off limits. It’s the sort of weapon that is really difficult to get “just right”, and so it’s no surprise that experiments would confirm that it’s tough. Hence dirty bombs have never scared me all that much.
Still, I would like to encourage terrorists to try to carry out the sort of attacks that require them to first rob a research lab or hospital radiology department. Any attack that first requires a theft from a secure (hopefully secure?) facility will be easier to detect than an attack that can be accomplished with commercially available supplies (e.g. improvised conventional explosives).
So, have at it, terrorists. Pour your efforts into attacks that require theft and great precision.
Comment by Gsnorgathon —
February 22, 2007 @ 8:25 pm
Dirty bombs never scared me all that much, either. Besides, can’t someone just make a soap bomb to clean up the mess?
Comment by michael holloway —
February 22, 2007 @ 8:28 pm
Too many qualified Offerings on that take – interesting though.
Comment by solarjetman —
February 22, 2007 @ 9:14 pm
The lion’s share of the harm caused by a dirty bomb wouldn’t be the actual physical harm directly caused by the radioactive material, but the mayhem and fear that would ensue as soon as the population of a city found out that it went off. And that doesn’t depend at all on how well-designed the dirty bomb is; all it takes is an announcement and a few guys in yellow suits with ticking Geiger counters on television and people will start thinking of the three-eyed fish from The Simpsons. People who haven’t taken any physics classes have a tenuous at best understanding of radioactivity, and they can be quite irrational about it.
Comment by Laertes —
February 22, 2007 @ 9:29 pm
“People who haven’t taken any physics classes have a tenuous at best understanding of radioactivity, and they can be quite irrational about it.”
Indeed. In the immediate aftermath of an attack, I imagine citizens will exhibit extreme skepticism toward statements from first-responders or government officials on the order of “remain in the tower” or “the air at the site is safe to breathe.”
Comment by jlw —
February 22, 2007 @ 10:23 pm
Didn’t the AIP or APS have a big report on dirty bombs back in the 2002 timeframe? Since then, I’ve always considered them to be really “real estate bombs”–barely budging cancer rates above background, but destroying billions of dollars in equity and gutting tourism and agriculture in an area about 100 times the actual affected area.
That gives you two ideas of the best places to set one off–in Manhattan or the Loop, obviously, but also in a branded agricultural region, such as the Napa Valley or Florida citrus area. Who’s gonna want to drink Florida orange juice after a dirty bomb goes off in Orlando?
Comment by Thoreau —
February 22, 2007 @ 10:33 pm
In the immediate aftermath of an attack, I imagine citizens will exhibit extreme skepticism toward statements from first-responders or government officials on the order of “remain in the tower†or “the air at the site is safe to breathe.â€
To play Devil’s Advocate for a moment, there are plenty of good reasons to not trust the government on, well, anything. But, yeah, ignorance will surely make it easier for unfounded fears to grow out of control.
And, IMHO, the greatest damage harm resulting from a dirty bomb will be the damage inflicted by the US military on whatever country we decide to retaliate against. Note that the country we retaliate against may or may not be the one that the attackers and their financial sponsors come from. (see: 9/11, Iraq War, Saudi Arabia)
Comment by John Emerson —
February 22, 2007 @ 11:35 pm
During the anthrax scare I researched as well as I could. The two problems with anthrax are the one you mantioned (making particles fine enough, and keeping them from clumping) and second, that anthrax is treatable with penicillin or other antibiotics.
Apparently the USSR solved the dispersal problem, because 64 people were killed in an accidental release in 1979 (Sverlovsk). Whether this was antibiotic resistant anthrax I don’t know; it seems equally likely that secrecy and poor medical practices were responsible for the deaths.
My guess is that anthrax was chosen because 1.) the spores are extremely hardy and durable, and 2.) by the time anthrax produces obvious symptoms, it tend to be fatal. The fatality rate during the 2001 scare was lower than it had been before, though, suggesting that anthrax’s historically high mortality rate is because of late diagnosis of a very rare disease (normally 1-2 cases a year in the US.)
I’d like to see someone follow up on this. I’ve considered the possibility that weaponized anthrax has been a 50-year boondoggle, but I wouldn’t be able to argue that.
Comment by jeet —
February 23, 2007 @ 8:51 am
Don’t radioactive elements also tend to be very, very dense?
Comment by Thoreau —
February 23, 2007 @ 9:02 am
Don’t radioactive elements also tend to be very, very dense?
The trans-uranics are. I hear that hospitals sometimes use radioactive isotopes of otherwise stable elements (forget which ones they use, but as an example, carbon is generally stable but carbon-14 isn’t). So they could use a lighter element, perhaps.
Anyway, a very fine particle of a heavy element could still travel a long distance. But that greater density just further complicates matters, by requiring an even tinier particle (which is difficult to achieve).
Comment by matthew hogan —
February 23, 2007 @ 10:41 am
The only good WMD is a real geunie exploding nuke WMD; other stuff is moslty hype; though obviously they can kill, injure, and do real psychological damage.
Comment by Donald Johnson —
February 23, 2007 @ 1:10 pm
There might be a lot of traffic fatalities after a dirty bomb attack, so they could be deadlier than a conventional bomb in that way. On top of the harm to the economy from rational or irrational fears about radioactivity. I won’t comment on the rationality of a hypothetical attack, but no doubt the mere mention of the word “radioactivity” would cause people to imagine illnesses where none exist. I knew someone who claimed that radioactive releases from the local nuclear power plant were causing trees to die several miles away. He didn’t seem to know that in that case people would be vomiting and dying in quite noticeable numbers.
And then there was someone in the medical profession who told me once that after Chernobyl she noticed an increase in problems in pregnancy– in NYC. I have no idea if what she noticed was a statistically significant rise, but if so I rather doubt it was from the radiation release.
Comment by Donald Johnson —
February 23, 2007 @ 1:12 pm
“I won’t comment on the rationality of a hypothetical attack”–Um, I left out a few words there. I won’t comment on the rationality of fears people might have after an attack not knowing what sort of attack we’re imagining. That’s what I meant.
Comment by Barry —
February 23, 2007 @ 3:52 pm
“Apparently the USSR solved the dispersal problem, because 64 people were killed in an accidental release in 1979 (Sverlovsk). Whether this was antibiotic resistant anthrax I don’t know; it seems equally likely that secrecy and poor medical practices were responsible for the deaths.”
And the release might have been, shall we say, ‘industrial-sized’.