Wednesday, December 28, 2011

Another Look at CFATS and Weapons

A topic that comes up from time to time in discussing security plans at high-risk chemical facilities covered under the CFATS program is the question of whether or not security personnel should be armed. Generally speaking chemical facility management is against fire arms and security personnel (myself included) tend to favor their use. The issue came up again in a rather odd context last week in the first of two reports by Mike Levine.

Mike quoted from the as of yet unseen internal DHS report on problems in the implementation of the CFATS program:

’Despite their lack of law enforcement authority, some still actively seek the right to carry a firearm,’ the internal report reads.”

The reason that I mention this here is that it is very important that everyone at DHS, especially the CFATS inspection force, understand why chemical facility managers are typically so adamant about no firearms being allowed on their property. It is not because they are anti-gun nuts (I personally know at least a couple that are card-carrying NRA members), but rather they are scared to death of what a gun can potentially do on site.

Flammable Atmospheres

Almost every chemical facility worthy of the name houses one or more flammable chemicals. A very safe chemical facility will take excruciating pains to ensure that those chemicals remain confined in the appropriate storage or processing systems. Even so, they know that small spills and releases are almost inevitable. Less safe facilities will, almost by definition, have more and larger such releases.

Even the smallest spills of flammable chemicals (ones so small that even the most rabid environmentalist would ignore it) result in a small cloud of flammable vapors. Under the right atmospheric conditions even those small clouds can be ignited by stray sparks and open flames. This is the reason that hot work permitting and flammable gas testing procedures are such an important part of chemical safety programs.

Before any work is done at a chemical facility that could produce sparks (drilling, grinding, etc) or introduce open flames (welding or cutting) a gas test meter is used to determine if there is the presence of a flammable atmosphere. A flammable atmosphere is defined as any concentration of a flammable vapor above the lower explosive limit (LEL) and below the upper explosive limit (UEL). Every flammable chemical has its own characteristic LEL/UEL combination.

These are called ‘explosion limits’ for a very good reason. The flammable vapor/oxygen ratio is so favorable for burning that the cloud ignites easily and burns very quickly, producing heat and a rapidly expanding cloud of combustion products that produce a pressure wave that can cause extreme damage at quite some distance for the site of ignition.

Generally speaking the larger the amount of the flammable chemical that is released into the environment the larger is the chance that at least some portion of the vapor cloud will be within the explosive limits for that chemical. And the larger that explosive portion of the cloud is the larger is the area that will be affected by the resulting explosion.


Handguns, rifles and shotguns are often generically referred to as firearms. The reason for this is clear; it is the burning of a propellant charge in the chamber of the weapon that causes the expansion of gasses in the barrel that, in turn, cause the projectile to fly towards its intended target at high-speeds.

Anyone that has seen a firearm discharged at night will have had a clear vision of the muzzle flash that accompanies the firing of the bullet. That muzzle flash (and cylinder flashes from revolvers) is nothing more than gasses that are still burning as they leave the confines of the weapon.

Those burning gases are almost certainly hot enough to ignite a vapor cloud that is within the explosive limits for that particular chemical. Depending on the size of the vapor cloud (which is again dependent on the size of the chemical release) the discharge of a single round from even a small handgun could result in a catastrophic explosion.

Bullet Holes

As it that weren’t problem enough, the projectile that leaves the barrel just before the muzzle flash is going to travel some considerable distance from the weapon before air resistance and gravity combine to bring it to earth. That can be quite some distance, something that even the most ardent shooter frequently forgets. Unless, of course, something gets in the way first.

Most people have no concept of the penetrating power of modern bullets. Having seen their favorite cop or detective on television hiding behind car doors in a gun fight, they assume that thin pieces of sheet metal are impervious to bullets. Nothing could be further from the truth. Even the rounds from small pistols can easily penetrate the walls of most storage tanks and smaller chemical storage containers.

If the bullet penetrates the container or tank below the liquid level the chemicals inside are going to come out the bullet hole. The rate will be dependent on the caliber of the bullet and the viscosity and flow characteristics of the chemical. Most really dangerous flammable chemicals will flow out of even a 0.22 caliber hole at quite an astounding rate.

For flammable liquid storage tanks, the higher the liquid level inside the tank above the bullet hole the faster the chemical is coming out. Under the proper conditions of bullet hole size, and pressure the liquid will convert to a vapor upon exiting the tank, greatly increasing the chances for forming a flammable atmosphere.


If an armed security guard or responding police officer encounters and armed terrorist who has penetrated the perimeter security measures of a high-risk chemical facility it is very likely that a gun battle will ensue. While every attempt will certainly be made to just hit the intruders with the bullets, the sad truth is that in any gun battle most bullets miss their intended targets.

The larger the chemical facility, the more likely it is that the ‘missing’ bullets will hit storage tanks, containers or process equipment resulting in the release of chemicals. If flammable chemicals are on site, the longer the gun battle runs the more likely it is for a flammable chemical storage tank or container to be hit by a stray bullet. And sooner or later it is likely that a firearm will be discharged within a flammable atmosphere. Then the probability of a successful terrorist attack will increase dramatically.

Guards Must be Armed

I am firmly convinced that if a security force is going to have any chance of preventing a successful armed assault on a high-risk chemical facility it is going to have to be armed. But, as I have explained here, arming them with firearms can be counterproductive to say the least. A security force manager is going to have to look for alternative weapons for facilities with significant amounts of flammable chemicals on site.

Interestingly, just yesterday the folks at published a copy of a DOD Non-Lethal Weapons Reference Book. While many of the weapons discussed in this book are firearms based, most are not. I strongly recommend that any security force manager should look over this reference for ideas for alternative weapons for interdicting terrorist attacks.

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