Fake Dynamite Prompts Evacuation

Yes, it's yet another story of knee-jerk overreaction to a nonexistent threat. But notice that the police evacuated everyone within a mile radius of the "dynamite." Isn't that a little excessive, even for real dynamite?

EDITED TO ADD (12/14): Assuming that this information is correct, this was an intentional hoax. The fake dynamite consisted of road flares duct taped together and attached to the side of the home.

Posted on December 6, 2007 at 6:43 AM • 79 Comments

Comments

WooDecember 6, 2007 6:57 AM

Unfortunately, the article doesn't state what the dynamite really was... (or I was too blind to see it.)

I'm eagerly anticipating New Year's Eve in the US.. I mean.. what are the police going to do when there's tons of REAL explosives for sale? Evacuate a whole city and preemptively blow up every fireworks delivery truck that drives in?

AnonymousDecember 6, 2007 7:08 AM

One-mile radius. Hm.

Perhaps the fake dynamite was strapped to some fake plutonium.

Nicholas WeaverDecember 6, 2007 7:13 AM

Uhh, did you SEE how far they had to get out of the way when they blew up that cement truck on Mythbusters? Shrapnel can fly FAR!

And that this was not some random device, but may have been placed because the owner of the motorhome had no idea where it came from and is the one who called the cops?

SparkyDecember 6, 2007 7:24 AM

(video in question in homepage link)

@Nicholas Weaver: that cement truck contained a couple of tons of explosives. The actual amount found in the motorhome is not specified, but it sounds like a few kilos at most.

PaeniteoDecember 6, 2007 7:27 AM

Assuming for a moment that it had been real dynamite, a mile does not seem too excessive, depending on the amount.
A shock-wave from an explosion can break glass in a relatively wide radius and you don't want to sit next to an imploding window.
(As I am writing this, I am looking out through a window several square meters large. It visibly vibrates when someone forcefully opens/closes the office door.)

Apart from this, the evacuation radius is CYA-security again.

BenDecember 6, 2007 7:40 AM

If it really looked like dynamite, and it was found unexpectedly in someone's home, then treating it as a potential bomb doesn't seem like an overreaction.

Mr. MikeDecember 6, 2007 7:55 AM

I'd say the 1 mile radius was a little excessive.

While stationed overseas, the base I was at had an accident where a bomb fell off the loader. I cannot recall if it was a 500lb or a 2000lb bomb. Forturately it did not go off. In that case, they only evacuated a 1/2 mile radius while they made sure the munication was safe to pick back up.

How I know, the dorm I was in was in that 1/2 mile. :-)

Compairing both cases, the munication, with specific design to destroy things with refined high explosives is a far order of magnatude larger than anything this dynamite case could of been.

Of course I've heard that a bullet can travel a mile, and that is nothing more than a piece of lead propelled by black powder (weaker than dynamite). They may be afraid of shrapnel flying that far. But with that logic, should we evacuate everyone within a mile when we see a stray un-fired bullet laying around. :-)

HaseDecember 6, 2007 8:19 AM

You can't always expect the average officer, or even an entire shift, to know everything about everything. Generally, I agree with Bruce's assessments of such things but this time, I don't think it was unreasonable. As an officer, you recognize a threat (notice this was not an abandoned bag or cell-phone), and deal with it quickly, the best way you know how. I'm sure the none of the officers, and probably few if any of you commenters, before reading this, could calculate the effects of a specific amount of dynamite sitting in front of you on the fly. These are cops, not explosives experts.

JohnDecember 6, 2007 8:21 AM

Perhaps the concern wasn't the blast radius, but the range of any wireless transmitters connected to the detonator?

John RidleyDecember 6, 2007 8:30 AM

@John:
If they're concerned about the radius of a wireless transmitter for the detonator, the most common detonator these days is a cell phone. To make sure nobody can set it off, you have to evacuate the planet.

QuercusDecember 6, 2007 8:30 AM

@Hase: No, we shouldn't expect the average officer to be an expert on the appropriate evacuation radius for a given amount of random explosive. However, as far as I know, most police these days do have radios and telephones. I don't think it's unreasonable to expect that the department have someone on call (in the department, or at a state unit) who is an expert on safe bomb disposal, including appropriate evacuation areas.

Nobody's perfect, and this isn't the biggest mistake ever. It's worth talking about, though, because all too often there's an attitude that going too far for security can never be a mistake. That attitude needs to be fought, because as Bruce points out security always has a cost, and spending too much (in money or inconvenience) is just as big a mistake as spending too little.

jeremiahDecember 6, 2007 8:33 AM

@Nicholas Weaver:

That was enough explosive to blow up a cement truck, 3/4 filled with set cement. They used probably 300 lbs of high explosive to do the job, and they went overboard for the cameras.

A few sticks of dynamite is a lot less than you'd think. In comparison to more modern explosives, all dynamite does is make a bang. A one-block evac would have been sufficient if there were less than 10 sticks and it was real.

(I was trained in explosives while in the USAF.)

bobDecember 6, 2007 8:43 AM

@Mr. Mike: Well, they used to be propelled by black powder; since about WWI they have been propelled by "smokeless powder" which is a "high" explosive and capable of much greater velocity. That said, a bullet can only travel any distance at all when the energy of the propellant is focused by a firing chamber (I.e. a firearm). A cartridge firing by itself (sans firearm) will not accelerate a bullet significantly, instead the brass holding the propellant will explode like a very tiny hand grenade.

If anything, the bullet side of an exploding cartridge is the safest side to be on, as the brass disintegrating on the other 5 "sides" will move farther and faster, possibly fast enough that if a brass fragment hit a really sensitive area (like an unprotected eye) it would do permanent damage.

blaisepascalDecember 6, 2007 8:57 AM

@Bob. Smokeless powder burns real fast, but it isn't (intended) to be a "high explosive". High explosives are characterized by a shockwave moving through the explosive. Such shockwaves tend to do bad things, like break the gun.

John WDecember 6, 2007 9:00 AM

@Paeniteo: Assuming for a moment that it had been real dynamite, a mile does not seem too excessive, depending on the amount.

A shock-wave from an explosion can break glass in a relatively wide radius and you don't want to sit next to an imploding window.
_________________

True. It's normal, and often responsible, to exaggerate the lines of evacuation. If you underestimate even a little, someone can get hurt, so over estimating leaves room for ever.

Another consideration is that of human behavior. If it was real dynamite and an explosion did occur (or of people got word that something was happening) people have a tendency to rush to see what happened. That's why we teach kids to yell "fire" instead of "help" when they are in trouble--yell fire, and everyone comes running. The excessive radius took into account any miscalculations about the impact of a possible explosion and kept people further away if something were to occur.

Just a couple weeks ago, there was an explosion at a power plant a half mile from my home. My wife and I stood in the front yard and watched the smoke. We were surprised at the number of neighbors that got in their cars and drove over to see. Fortunately, no one was hurt as the plant was just built and being tested. However, had it been worse, all the gaukers certainly could have got in the way of emergency service personnel.

jdDecember 6, 2007 9:09 AM

That's because most people are getting dumber by the minute.
If everyone's hygiene matched their level of education in math and physics, they would live like in the 1400s. That means bathe once a year and no toilet paper.

Mark J.December 6, 2007 9:10 AM

It may have been "nucular" dynamite, after all. Send the owner of the motor home and anyone who knows him to Gitmo.


But don't tell anyone.

Paul CrowleyDecember 6, 2007 9:25 AM

Being generous...

How expensive was that one mile? If there was very little around besides a truck and two sheep, then maybe the costs of the one-mile radius were so low it wasn't worth getting expert advice on what a more realistic radius would be.

Alan BragginsDecember 6, 2007 9:32 AM

One mile might also be sensible if you are worried there are more sticks of dynamite around that you haven't found yet.

PaeniteoDecember 6, 2007 9:39 AM

@Paul Crowley: "How expensive was that one mile?"

In the article it says something about "more than 200 homes". Assuming an even distribution of homes, halving the radius would have reduce this number to "more than 50 homes".

But you are right as you mentioned the cost: To the authorities, that cost is an externality.

RKDecember 6, 2007 9:56 AM

Emergency responders use the Department of Transportation's Emergency Response Guidebook[1] for determining evacuation distances. Guide entry 112[2] deals with unknown explosive (113[3] deals with wetted TNT specifically) and recommends an initial evacuation of 1/2 mile with a note that fragments can travel a mile or more. A mile is recommended for a rail car or trailer involved in a fire with suspected heavily encased explosives.

[1] http://hazmat.dot.gov/pubs/erg/gydebook.htm
[2] http://hazmat.dot.gov/pubs/erg/g112.pdf
[3] http://hazmat.dot.gov/pubs/erg/g113.pdf

anonymousDecember 6, 2007 10:10 AM

A mile still seems extreme even for metal shrapnel.

From the back of the envelope ... a stick of dynamite is just a bit less than 100cm^3. Guessing at TNT-like density of around 1.7 gm/cm^3. That's about 170g ( a bit more than 1/3 lb) per stick. A bit hard to know with an "unspecified" amount, but to match the 500lb'er that would be roughly 1500 sticks, and probably about double based on relative yields.

A bullet can fly a mile because of the black powder and the gun. Take it out of the chamber and it's far less dangerous. Going back to Mythbusters, in the last week, my local aired an episode where they put shells inside an oven and baked them. Even with 50 cal they couldn't break the glass window. The lighter casing did more damage than the bullet. They finally had to put a loaded gun in the oven to get it to work.

I'd be more worried about glass shrapnel from the motor home which could be nasty and is light enough to throw a long way.

John WDecember 6, 2007 10:13 AM

@RK:

Great post. Thank you.

With hindsight, a mile may have been too much. But with what they knew at the time, having to make an immediate decision on a probably unknown explosive, one mile does not seem unreasonable, especially given the references you cited. Far better to overestimate than underestimate.

Regards,
John

AndrewDecember 6, 2007 10:16 AM

@RK

I was also thinking of the protective action distances in the ERG.

This is why firefighters (who get some engineering training and have access to Real Engineers) need to be involved in these complex scenes and situations.

John WDecember 6, 2007 10:16 AM

@Paul Crowley: maybe the costs of the one-mile radius were so low it wasn't worth getting expert advice on what a more realistic radius would be.
_________

Fair enough. Perhaps, also, the time it would take to get expert advise was too costly. Thankfully, it was a false alarm, but I sure would rather be in a position explaining why I evacuated too large a radius than too small of one (unless it was a clearly absurd radius...which this one doesn't seem to be).

NateDecember 6, 2007 10:25 AM

The article said they used an automated emergency telephone warning system. I wonder if it has a minimum resolution of a mile which might explain this.

AnonymousDecember 6, 2007 10:31 AM

@John W.: Happy to provide some meat.
--
Given no information beyond the linked-to article, I don't think a mile was unreasonable. I conjecture that some of the 200 homes evacuated were also mobile homes; many of them probably had propane tanks. Propane, that's guide entry 115, also a 1/2-mile evacuation distance (1-mile for rail cars and tankers, too, with notes about containers exploding and rocketing). The Contra County Sheriffs will get no criticism from me.

Pierce NicholsDecember 6, 2007 10:43 AM

1 mile is completely excessive. 1250 ft (approx 1/4 mile) is what is called out for quantities of explosives up to 15 tons TNT equivalent in the DoD's explosives siting guidelines (DoD 6055.9, for the curious).

StephenDecember 6, 2007 10:43 AM

"it's possible to calculate that it would require 155 TONS of TNT to create an explosion that would break windows at one mile."

That's an exaggeration. The Enschede explosion in 2000 broke windows at 2 km. That was caused by about 140-150 tons of fireworks, equivalent to about 20-25 tons of high explosive.

But yes, based on the amount of dynamite that one could quickly slip into a motorhome while the owner was away, I'd feel safe enough at 400 metres, and probably at quite a bit less.

jdegeDecember 6, 2007 10:43 AM

How far is safe?

It depends as much on what's being cut, than what's being exploded.

I stood 50 feet away from an M19 AT mine, once, when it went off. Plastic case, no shrapnel, sitting flat on the ground. No big deal (though my platoon sergeant had a quiet word with the squad leader, after.)

I've set off 2000 pounds of ANFO buried under ground. Rocks and dirt flies for hundreds of yards.

But the one time I was scared was with only a couple of pounds of C4, cutting a steel I-beam. We were maybe four hundred yards away, having stepped out from behind the protection of the track to watch, when it went off.

Not a big explosion, not a lot of noise.

But a small piece of steel went whistling by, just over our heads. It missed us, but it it something, a mile or so back through the woods.


RKDecember 6, 2007 10:53 AM

@Andrew: The article is thin on details, but I imagine there were fire units on scene or standby for this as well.

@Paul Crowley: All the fire and EMS response units I've seen carry the DoT's ERG. I've seen it knocking about local and state police cruisers. As far as non-HazMat responders are concerned, consulting the ERG *is* consulting the experts until either the HazMat team or bomb squad show up.

@Pierce Nichols: I doubt the Contra Costa County (CCC) Sheriff's department uses Department of Defense guidelines for their response; local emergency response is guided by the Department of Transportation. You make a valid point, though, in as much as the DoD materials experts and the DoT material experts might find a conversation amongst themselves useful to see if there is some discrepancy in their understanding. It could be that the difference is in a military verses civilian context.

@jdege: Indeed. I've been taught, because I am not a HazMat or bomb technician, to think of all explosives as a person armed with a rifle aimed in all directions. G.T.F.O.

The more I ponder this case (with an admitted derth of information), the less I find fault with the CCC Sheriff's response. If folks want to question the appropriateness of the size of the evacuation, you need to make your case with the materials experts who contributed to the DoT's ERG.

RoyDecember 6, 2007 10:56 AM

That 1 mile radius means about 3 and 1/7 square miles evacuated, and 200 homes utterly without protection. (Burglar alarms will not be answered for the duration.)

Burglary teams now know how to get the police to get the people out of the homes they want to take off, and keep anyone from interfering for several hours.

Bring in teams in vans. Call the rover to call in the 'dynamite' story, then wait for the police to clear everyone out. Then take off the house, put everything in the van, and wait inside until the all-clear. Drive away with the loot.

Over-reaction? Let's call it an extremely lopsided reaction.

WoodyDecember 6, 2007 11:35 AM

As another first responder (Fire/EMS), when we had a "unknown substance" reported as dynamite, it was a 1/2 mile radius hot zone, with another 1/4 mile warm zone. But there were two houses in the entire area, both in the warm zone. We told them to stay indoors (we'd already checked with HazMat, who were en route).

It was a box of nylon airgun pellets made by Dynamit Nobel.

This was right after the anthrax scares post-9/11, so a broken open box of white granules on the side of the road got everyone far more excited than it should have (our dept and the county HazMat team were pretty skeptical, but still kept our distance).

WoodyDecember 6, 2007 11:37 AM

Edit: It said it was from "Dynamit" on the side of the case, and HazMat took a sample and tested to verify it was just plastic (nylon).

AnonymousDecember 6, 2007 11:51 AM

>the police evacuated everyone within a mile radius of the "dynamite." Isn't that a little excessive, even for real dynamite?

- Dominos

Nomen PublicusDecember 6, 2007 12:01 PM

So, as I am a world class criminal, all I have to do is wrap some lengths of cardboard tube with brown waxed paper and leave them somewhere for someone to find. The police will kindly move the entire neighbourhood out of the area and I can burgle some houses in peace...

Sometimes, the pointy end of the stick is not the end to worry about.

giannaDecember 6, 2007 12:19 PM

Possible Scenario:
Sheriff: Deputy, what sys the handbook.
Deputy: Half a mile, Sir!
S: How many homes?
D: About 50, Sir.
S: Double the radius, that's just a 50 homes more.
D: But the are of a circle grows with the square of its radius.
S: ??. Dont talk giberish with me, follw my orders.
D: But sir..
S: FOLLOW MY ORDERS.
D: Sir, Yes Sir!

Huh?December 6, 2007 12:34 PM

It’s amazing to observe a bunch of widely-speculating, non-professional skeptics debate a topic they have at-best, a tiny fragment of knowledge about. This is what the Internet has created?

RoyDecember 6, 2007 12:47 PM

A few years ago a tractor trailer spilled a load of chemical bags. The cops cleared the entire area, assuming the worst. They did let the news cameras in close enough for me to read the labels -- ferric oxide -- which is basically iron rust. It took nearly an hour for a hazmat team to get there to evaluate the situation.

That situation, like the current one, requires a qualified person to make decisions, not an unqualified one.

KyleDecember 6, 2007 12:53 PM

*agrees with Huh?*

RK did a great service by pointing out actual facts rather than relying on inexpert opinions by folks trying to assess the seriousness of a threat without a deep understanding of the underlying considerations.

Just what drives us infosec people nuts.

Also, Schneier's somewhat unfair in his post. It was NOT a nonexistent threat in the sense that, upon first examination, it evidently looked like dynamite. Should the local cops have had everyone remain in their homes pending a closer investigation? Or what other course of action should they have taken instead?

There are times I agree with Schneier about overreaction, but this isn't one of them. Hindsight is 20/20, and if it had turned out that it was in fact dynamite -- an unknown fact at the time -- then I believe this would all be a lot more muted.

dragonfrogDecember 6, 2007 2:30 PM

Interestingly, the story stacy posted says

"After inspection, it was determined that what had appeared to be a bundle of dynamite attached to a timer and antenna wrapped with duct tape was nothing more than a handful of road flares."

But of course they blew the thing up first, just to be safe, then inspected what was left, I guess.

From the attached picture, you can see that the controlled detonation blew a hole in the fellow's wall. Interesting - the attacker had explosives probably only powerful enough to leave unsightly scorch marks on the wall, but managed to get the bomb squad to do more serious damage to the house...

periDecember 6, 2007 4:24 PM

@Ian Mason and RK: thanks for the awesome links!

Here is Ian Mason's 1 mile blast radius actually centered on Knightsen:
http://meyerweb.com/eric/tools/gmap/hydesim.html?ll=-121.665538,37.969189&yd=0.155

http://en.wikipedia.org/wiki/Knightsen

Wikipedia says Knightsen has 861 people in 281 households. This evacuation represented ~75% of the houses in Knightsen, lasted from 2:30 pm to about 6:30 pm! Imagine being the elected police official who evacuated 3/4 of Boston for Lite-Brites or a student project! Sadly, Knightsen only represents about 1% of the county population and the evacuation was conducted by county officials. Now I am really curiuos to see what would happen in tiny town where a police official's election pool is almost entirely evacuated for a false alarm.

Paeniteo's 50 homes came from "200 homes within a mile" and a little math:
200 homes = pi * (1 mile)^2 ~ 3.14 square mile (~64 homes in 1 square mile),
pi * (1/2 mile)^2 ~ 0.79 square miles or ~51 homes and
pi * (1/3 mile)^2 ~ 0.35 square miles or ~22 homes.

Putting all this together suggests to me that 1 mi. is probably excessive for even as much as 3 pounds of dynamite (9 sticks, thanks anonymous); still I am quite grateful the DoD experts seem not to leave up to a county sheriff to determine whether that pile of stuff is road flares, a few pounds of dynamite or ten pounds of C4. As jdege's narrative suggests it takes only a little of the _right_ stuff for shrapnel to be dangerous even a mile away and agree that some untrained county sherrif should be trusted to determine whether it is the _right_ stuff.

AnonymousDecember 6, 2007 4:29 PM

It was all just a ruse so they could use the water cannon with no one watching.

AnonymousDecember 6, 2007 4:34 PM

A few years ago an American bomb was found on our property. During WW2 there was an aircraft factory across the street, and during one bombing night several houses in the neighborhood were destroyed by stray bombs when this factory was attacked. This one obviously was a dud, it buried itself several feet underground, lying only inches from the basement wall of the house for over 50 years. It was discovered during construction work when an excavator was digging a hole and brought the bomb to the surface.

We immediately called the cops, and they evacuated the surrounding houses and blocked the road. Then the unexploded ordnance guys arrived, had a look at the bomb and demanded a bigger evacuation. The radius of the evacuated area was several hundred meters (maybe 500?), but certainly not a mile. And this was a real bomb weighting in at several hundred pounds filled with military high explosive! It was severely rusted on the outside, but the detonators were in excellent condition. They showed us when they were done defusing the bomb.

Here in Germany thousands of bombs and shells and other leftovers from WW2 are found every year. In some areas you can pretty much count on some shit showing up when the excavators start digging. A relative once discovered the remains of a German officer in her backyard who apparently was executed there by Russian soldiers during the last days of the war. He was lying only about a foot below the ground and was only found 30 years after WW2 ended!
An old grenade, the equivalent of this "dynamite" certainly isn't reason enough to evacuate several square miles over here, and it happens all the time.

I wonder what the usual evacuation radius is when the glorious Unites States Armed Forces defuse IEDs or unexploded ordnance e.g. in Iraq or Afghanistan. Do they evacuate the local population in a one mile radius too? or maybe not since we are only talking about brown people here which are all potential targets anyway...

JamesDecember 6, 2007 4:48 PM

A mile does seem to be overkill. The IRA bomb at Bishopsgate in London contained an estimated 1000kg of ammonium nitrate/fuel oil. It showered debris for about 150m. The bomb the IRA detonated in the centre of Manchester on father's day the same year was apparently about half as big again. That was in a truck (see video http://news.ninemsn.com.au/article.aspx?id=105611) but I guess you could fit that much explosive in a mobile home.

Could you tape it to the side looking like sticks of dynamite? I'd say not.

Consider the alternative though; the UK police didn't evacuate people far enough for the 1996 bombing of Manchester and 200 people were injured (though fortunately there were no fatalities).

AnonymousDecember 6, 2007 4:57 PM

Oh yeah, the roadblock which I talked in the above post (the US bomb on our property) lasted only about 2 hours, and the actual defusing took only a few minutes.

There are of course formulas available which are used to calculate the dangerous area for a known amount of explosive.

Here in Germany the following formulas are used:

safety distance (meters) = f * cubic root[explosive mass in kilograms]
f is some factor depending on circumstances.

Example:
distance between an explosives storage area (e.g. 30 tons) and regular living quarters: f=22

distance = 22* cubic root (30000kg) = 682 meters

So if you want to store 30 tons of explosive, the distance to the next inhabited house must be 680 meters. NOT A FRIGGN' MILE!

when there is danger of heavy shrapnel: f=76, but at least 275 meters


distance between explosives storage area and road; f = 15, distance at least 180 meters

rockets and grenades, danger of explosive article flying away and exploding on impact:
living quarters: f = 58-76
roads: f = 39-51


RKDecember 6, 2007 5:48 PM

I'll repeat my earlier suggestion: anyone who would like a change in this evacuation policy should feel free to contact the United States Department of Transportation[1]. Offer them your advice, research and credentials supporting your suggestion of reducing the suggested evacuation area. I look forward to a 2008 Emergency Response Guide with your revised guidelines.

[1] http://hazmat.dot.gov/contact/whoweare.htm

RKDecember 6, 2007 6:10 PM

Heh. Not quite, Anon. Just a local responder (in the U.S.) that uses the US DoT ERG. Having identified the source of the evacuation policy, it is fairly pointless to quibble about it here. If you would like to affect a change, take your concerns to the source.

AnonymousDecember 6, 2007 6:17 PM

RK sounds more like someone who is saying people are sneering at the wrong folks. The cops just followed their guidelines; instead of taking issue with them, it would make more sense to take issue with their guidelines.

periDecember 6, 2007 8:05 PM

@Anonymous
"Here in Germany thousands of bombs and shells and other leftovers from WW2 are found every year."
...
"Oh yeah, the roadblock which I talked in the above post (the US bomb on our property) lasted only about 2 hours, and the actual defusing took only a few minutes."


Your analogy fails pretty badly for a number of reasons: on the extremely rare occassion someone does discover a bomb in America, it must be dealt with by someone with almost no field experience, there is no manual on disarming it because each bomb's composition is unique and therefore unknown, it also has not been dormant for decades and unexploded bombs obviously missed their intended target. whereas bombs are generally placed precisely in the location it occupies to suit the attacker's purpose.

"safety distance (meters) = f * cubic root[explosive mass in kilograms]"

I am curious about the f the manual calls for when somebody seems to have placed the explosives with the intent of harming someone in a population center? The cubic root part makes sense considering the blast area is probably hemispherical; unless the charge has been shaped into, say a cone, in which case I think the debris area is conical and thus the square root is more appropriate.

http://en.wikipedia.org/wiki/Shaped_charge


For a 4 kg example consider:

f*square root(4) = f*2.00
f*cubic root(4) = f*1.59

The 4 kg shaped blast is now flinging debris 26% farther than the formula would have estimated and this error compounds horribly when you consider the danger zone's _radius_ is 126% of what you expected. For every 10 people evacuated based on a hemispherical 4 kg blast there are 6 who remain in danger if it is conical.

The error of course also compounds horribly as mass of the explosives increases. Consider 8 kg:

f*square root(4) = f*2.83
f*cubic root(4) = f*2.00

The radius is now 142% of the expected value. For every 10 people evacuated based on a hemispherical 8 kg blast there are 20 who remain in danger if it is conical.

I hope this clearly illustrates the difference between accident and attack. For the sake of completeness I should say that all people within a hemipsherical blast are in danger and might be hurt by blast debris. In the cone example a 45 degree cone means only 45/360 (12.5%) might be harmed, but 360/360 (100%) are in danger of harm because which 45 degrees is assumed to be unknown.

FreiheitDecember 6, 2007 8:46 PM

Irrespective of the evacuation radius a malicious individual now knows what that radius is.

So lets see how this movie plot works out:

1. Plant a noticable amount of fake (or real) explosives in an area where the responders evacuation radius is known. Should be planted approximately the evac radius from an area where the evacuated are likely to congregate such as a stadium, school or mall.
2. Ensure that noticable amount of ordinace is NOTICED. Call that bad boy in.
3. Wait for the evac to complete.
4. When you see/hear the bomb crew disable the device, detonate the device(s) you planted at the evacuation sites.

Its similar to the airport security problem. The masses of people are no longer on the plane, they are in the checkpoints. Where the people are also becomes more predictable to generate the best effect.

AnonymousDecember 6, 2007 9:34 PM

"If you would like to affect a change, take your concerns to the source."

Only a fool brings a bureaucrat's attention to their inherent incompetence.

And it's much more fun to laugh at them all from a distance -- maybe a mile? After all, ignorance is a far more dangerous substance than a few sticks of dynamite. Real-world proven again and again.

AnonymousDecember 6, 2007 9:47 PM

@peri: "on the extremely rare occassion someone does discover a bomb in America, it must be dealt with by someone with almost no field experience"

But we are being assured by @RK that the hazmat protocols and standards practiced in the USA are top-notch, designed to protect you and your property. Fully thought out, practiced relentlessly, and fine tuned with each iteration to near perfection.

If this means general evacuation for a mile for a few hundred grams of HE, who are we to disagree with Them?

That a bunch of over-educated Europeans are probably laughing themselves sick at this spectacle, knowing they can deal with an over-ripe, real, multi-hundred pound bomb >>designed to kill people and blow the shit out of property

AleksejsDecember 7, 2007 12:59 AM

Very valid point by Freiheit. In such a small town - there would not be many alternative choices (if any) as to where people are going to be evacuated. It makes this place an even more attractive target for terorists.

MDDecember 7, 2007 4:15 AM

The standard safety distance for a vehicle IED is 250 metres. For a single stick of dynamite in the open or a bag it would be 50 metres.

It may be that in this case they extended the range because camper vans often carry gas bottles for a cooker or an older style gas powered fridge. If the dynamite managed to detonate a gas bottle or two off, that would make life interesting for those in the vicinity.

AnonymousDecember 7, 2007 4:41 AM

peri, your shaped charge proposal doesn't prove anything. The projectile tip produced by the shaped charge will fly only a few meters before it totally disintegrates into small particles of metal. The "slug" (the rear of the shaped charge projectile) will move very slowly and is no big danger. Other projectile forming charges might behave differently though. Still, a mile is excessive. But we wouldn't expect any different from you yanks. :)

AnonymousDecember 7, 2007 5:27 AM

> The Enschede explosion in 2000 broke windows at 2 km.
> That was caused by about 140-150 tons of fireworks,
> equivalent to about 20-25 tons of high explosive.

High explosives produce stronger shock waves at close distances, but at longer distances the shock waves of low and high explosives are virtually indistinguishable. I doubt that the Enschede explosion can be compared to a 20 ton HE detonation, more like a 50-100t HE detonation with regards to long distance overpressure effects.

Ed T.December 7, 2007 6:40 AM

A Sheriff's Dept. rep said "... for us it was a no-brainer."

Finally, the authorities admit what we have known all along.

~EdT.

AnonymousDecember 7, 2007 7:15 AM

@Freiheit
It is a "based on a true story" movie plot then:

http://www.emergency.com/atlnabmb.htm

[1/16/97]
"As the preliminary investigation continued, a secondary explosion followed at about 10:30. The secondary device was reportedly larger than the first, according to witnesses."


@Anonymous
"The projectile tip produced by the shaped charge will fly only a few meters before it totally disintegrates into small particles of metal."

Ah so you are saying there is too much energy in the blast for it to be dangerous! Tank armor is blown through like a liguid at close range by the hypersonic tip, then the tiny particles flutter to the ground harmlessly like dust and all that dangerous enrgy is just gone. Obviously I missed that!

Anonymous CanuckDecember 7, 2007 8:21 AM

@RK - You've made some good points. But your comment on revising the evacuation policy rings wrong. Frustration?

Firstly, I agree that if the locals followed the official procedures they shouldn't be ridiculed. My take is that it is "the system" that is being debated.

And I'm with you - I'd rather not have people improvising this stuff. Great movie plot stuff. Good way to screw up.

I've seen people, smart people, miss obvious things under simulation/test stress. It's usually from lack of practice, sometimes procedures or training.

Postmortems on incident response are an effective way to see how well they work. Not just the responders, but the procedures, the training for the responders, etc. Lots of places where this sort of thing can go wrong. But you know this. Hopefully there is an official one on this. Or that includes this one.

There should also be some kind of regular review of the risk and effectiveness of these procedures. That's business as usual.

Maybe some of it will get the attention of people who maintain those procedures. Maybe something will come of it, or not. It just seems to me that "the system" isn't learning from itself. Could that be because it isn't getting all of the feedback?

I'd rather it be a bit conservative from a safety perspective. I still think it was excessive. But, I'll give you this, I don't know what has been lumped together in those procedures to justify the radius.

And the idea of glass shrapnel still worries me. A bit less with the sticks on the outside of the RV.

In any event, I think this is a healthy and interesting discussion.

@Freiheit - I think this tactic has been used elsewhere for a while now. And it’s scary.

RKDecember 7, 2007 9:26 AM

@AnonCanuck: Rings wrong? Not quite sure what you mean by that, but it's true that long debates on a blog about this sort of thing frustrates me. A number of anonymous comments flaming a policy is not going to amount to much. I'm all for healthy back-and-forth, though. My contributions were intended to feed some reference facts into the discussion. Any frustration sensed is probably my defense of those who do explosives research in the civilian sector and were involved in the formulation of the recommendations in the DoT ERG. I know some of them and their credentials; I don't know anybody here.

I was genuine, though, in my response to P. Nichols about the difference between the U.S. Department of Defense and Department of Transportation safe distances. Generally, I think that a review of policy and procedures is almost always a good thing. If there are explosives and hazmat experts who question the 1/2-mile to 1-mile evacuation standard, I would encourage them to offer their experience to the policy-makers. However much of a fool that makes me.

And you're right: we don't know what else contributed to the CCC sheriffs' decision to evacuate a mile. They could have taken the largest distance mentioned in the DoT ERG and ran with it. They could have identified secondary hazards on-scene (e.g. propane tanks, vehicles). We haven't heard from the responders about the details of their decision-making and we haven't heard from the evacuees about their opinion of the response.

anonymous canuckDecember 7, 2007 11:19 AM

@RK – To be frank, I though it sounded at bit defensive/sarcastic/annoyed. But then again, I'm not so close to it as you. Easier to be patient from a distance :)

I take a lot of the flames as general frustration. Not unexpected with some of the TSA issues and other published overreactions. Not so fair this time around.

Agreed, anything DOD/Military has a different risk profile than civilian. I recall that the US Navy Dive tables inherently would result in 5% of healthy, fit navy divers getting the Bends. I never heard the numbers on unhealthy civilians. The new sport tables are safer I hear.

Also, 200 homes is pretty sparse. In suburb or city home without any apartments, you could be looking at 15-60 times as dense. That’s a bit tougher decision to ponder.

The reasoned discussion seems pretty thorough, even if unvalidated. It would be interesting to hear from one of the DoT experts, did anything get overlooked? The answer could just be a safety margin. It could be systemic lack of experience. If like the Germans, you get a lot of legacy bombs then you’ve had more time to refine your procedures.

And I wonder how many layers are involved in the reasoning and decision making behind these numbers. It could easily be more than two. The DoT may have used the DoD distances or calculated their own. They probably added a safety margin. I’m sure the DoD distances incorporate a safety. Then, as you noted, the county’s responders add their own safety. Possibly more if there are enough decision makers in the loop. Each layer adds its own safety not thinking a lot about what has been built in already. The inner layer safeties are probably well thought out based on physics. If any discretion comes into it, the outer layer safety distances will probably be based more linear increase rather than increase in energy. Pretty soon, it gets very very big.

All of this is a bit like riding a wave. Err slightly either way and you get left behind or fall. People can’t be perfect and criticizing them for being people isn’t fair. Criticizing the system is fair but shouldn’t be confused with sport. The really hard questions are: How do we make the error bars around not being perfect bigger? How do we make it easier for people to succeed in these situations?

I do wonder about the real story. Who did it and why? Alcohol inspire prank? Teenage prank? Personal animosity? Theft?

Peter E RetepDecember 7, 2007 7:08 PM

Just a bit of perspective: I had a friend in the film trades in the 80's who drove out to location in a IH Scout, wore long hair, and carried a rifle in the back window to sleep out safely, along with lots of e-gear, and the occassional odd prop, which in the dark of one morning on the way to location was a crate of old "sticks of dynamite", when he was pulled over by the CHP, all in plain sight.
They did pull their pistols and ask him to step out and reverse to them. Then they asked him to explain. He did, they checked his 411, L & R, trades card, all had a good laugh, went to coffee together, and *zip* he was on his way to set up the set for a dawn shoot.
Today?

AnonymousDecember 7, 2007 11:59 PM

Several other people mentioned the DOT Emergency Responder Guidebook (ERG). For convenience (so you don't have to hunt through the links above), the 2004 version is the latest one, and is freely available here:

http://hazmat.dot.gov/pubs/erg/gydebook.htm

Commercial truck drivers and all emergency vehicles are required to carry a copy of this book. It does have recommended evacuation guidelines.

I would like to point out that most of the single press reports missed important elements of the event. Although it initially seems like an overreaction, the evacuation response seems appropriate.

The discovery of the apparent device occurred at approximately 1 pm by a patrol officer. The vehicle was a small-type motorhome, similar to the picture available here:

http://en.wikipedia.org/wiki/Image:Custom_Camper_Van_New_Zealand.jpg

The vehicle was parked at an angle, an unpaved street in Knightsen. This is an
unpaved residential street that dead-ends. From the news media TV clips, it appears that the vehicle was between two residences.

The area is rather sparsely populated, (you can view it pretty easily off of
Google Earth). Note that there is a gas station nearby, which might also be an additional hazard.

So the guy (or gal) in charge had a list of possible scenarios that went something like:

Is the device only an initiator for a larger quantity of explosives?

Are secondary devices present?

Is the device intended to be a dispersal agent as a combined threat (think
low-level radioactive materials, which is more of a PR problem than an actual danger, or maybe other biological agents)?

Is one of the residences a target?

Is it a fake device, or a real device disguised as a fake?

All in all, the response seems to have been scaled back to an appropriate level as more information became available. It looks as if the entire event was over within about 6-8 hours.

The local bomb squad detonated the device at around 5-6 pm. Traffic in the area was returned to mostly normal shortly thereafter.

AnonymousDecember 8, 2007 6:08 AM

> Is the device only an initiator for a larger quantity of explosives?
> Are secondary devices present?
> Is the device intended to be a dispersal agent as a combined threat (think
> low-level radioactive materials, which is more of a PR problem than an actual
> danger, or maybe other biological agents)?
> Is it a fake device, or a real device disguised as a fake?

Maybe the terrahrists are trying to make us believe that this is a real bomb disguised as a real bomb? or a fake bomb disguised as a real bomb since they know we will treat it as a real bomb even though we expect it to be a fake bomb which looks real? Shit now things get pretty confusing.

Maybe the camper is filled with sarin? Or maybe it contains a friggin' Russian 1megaton hydrogen bomb?

Is that camper filled

josephdietrichDecember 8, 2007 2:21 PM

Just for comparison, (and to back up one of the Anonymous commenters above) a few weeks ago an old American 1,100 lb. "Zehn-Zentner" bomb was dug up in the city I currently live in. This was in the middle of the town, and they evacuated everyone in a 500-meter radius (about 10,000 people) and shut down a local soccer match at a stadium about two kilometers away because of it. It was considered by most of the folks I spoke with as a major and unnecessary pain in the backside. Still, safety first and all of that.

But to evacuate a mile radius for what might be at most several pounds of dynamite? That just smacks of overreaction.

AnonymousDecember 8, 2007 3:14 PM

@anonymous: "Is the device only an initiator for a larger quantity of explosives?"

You can't find everything, you can't know everything, you can't prove a negative. Maybe any bomb so found is the trigger for the nuclear weapon? Conclusion: in the face of ignorance, you must evacuate the entire city, the county, the state.

"Are secondary devices present?"

See above.

"Is the device intended to be a dispersal agent as a combined threat (think
low-level radioactive materials, which is more of a PR problem than an actual danger, or maybe other biological agents)?"

See above. Are you getting the pattern yet? Any time some cop becomes suspicious, for whatever lunatic reason he can think of, do we shutdown civilization as we know it while they conduct their bumbling investigations, and blow some stuff up?

"Is one of the residences a target?"

What if it was? What if the target was a school? A hospital? An entire apartment complex?

Maybe I am strange, but it strikes me that bombs are bombs, regardless of their target, and are dealt with on their own terms, as opposed to what the target may or may not be.

"Is it a fake device, or a real device disguised as a fake?"

Let me guess: if the device is known to be a fake, the evacuation distance is reduced by 37.1% (a number decided after extensive committee consultation with a panel of experts convened by the blue-ribbon executive sub-forum of paid industry representatives), and the inconvenience factor is increased by 53.97%.

But if the real device is simply disguised to be fake, well, we must assume it is a 50MT cobalt bomb. In this event, the President appears on CNN and gives the National G.Y.S.A.K.Y.A.G.B. Speech - the text of which is conveniently located in the lower left drawer of That Desk in the Oval Office.

Of course, no evacuation is undertaken.

"All in all, the response seems to have been scaled back to an appropriate level as more information became available. It looks as if the entire event was over within about 6-8 hours."

I'm sorry, but in addition to the over-reaction, 6-8 hours to destroy a few sticks of dynamite is stupid.

David CantrellDecember 9, 2007 9:44 AM

John W wrote:

> there was an explosion at a power plant a half
> mile from my home. My wife and I stood in the
> front yard and watched the smoke. We were
> surprised at the number of neighbors that got in
> their cars and drove over to see

I'd be surprised at people using their cars to go a mere half mile too.

John WDecember 10, 2007 8:51 AM

@David Cantrell: I'd be surprised at people using their cars to go a mere half mile too.
___________

There were no sidewalks to get to where the plant is from our neighborhood, and the closest you can get on foot is across the lake. Best visibility is from the bridge, or from country roads that are over a mile to get to. Had it been different, more may have walked. I honestly don't know.

GeoffDecember 10, 2007 12:18 PM

@Bruce Schneier: Isn't that a little excessive, even for real dynamite?
______

Respectfully disagree, Bruce. And that doesn't happen often.

I work in a related field, and this would be due precaution in the event of an unknown explosive threat, for many reasons. It is better to exaggerate the fallout than underestimate it, you may not have time to diagnose it and apply specific protocol (such as knowing the proximity at risk), etc. As someone else mentioned, it not only gets people out of harms way, it reduces the amount of curious civilians getting in the way of responders.

I guess the best answer is this: the radius was beyond what was necessary, but a reasonable response given the information at the time. I'd rather defend a radius too large than a radius too small.

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