Wednesday, September 16, 2009

Security for 100 Propane Railcars

Thanks to the folks at, a transportation security discussion group, I’ve seen a copy of an article from about a study being conducted about storing up to 100 full propane railcars on an ‘unsecured’ rail siding in East Tennessee Technology Park in Oakridge, TN. This industrial park sits on a portion of the old Oakridge nuclear weapons development site. There were evidently not a lot of details available to the local blog writer and it wasn’t even certain that if the storage was eventually approved by the locals that it would even happen. What was interesting to me was the cavalier way that the lack of security at the site was completely overlooked in the article. Actually, this shouldn’t be too surprising. While the TSA does have a freight rail security regulation in place (49 CFR part 1580) propane is not considered to be a rail security-sensitive material (selected toxics, explosives and radioactive materials) that would be covered by that regulation. A rail siding storage location might be considered a chemical facility, but DHS specifically said in the pre-amble to the CFATS regulation that they were not currently addressing rail facilities. The reason that TSA did not include flammables in their freight rail security regulations was that a successful attack on a rail car full of propane would only affect a limited area. Typically a propane railcar will start to leak and the propane will catch fire. It will make an impressive fire and anyone nearby will get toasty real quick, but unless you are near a refinery or flammable liquid tank farm the damage will be very localized. The problem here is that 100 rail cars is a completely different proposition than one rail car. Readers of this blog will remember a couple of weeks ago I pointed them at a video of a BLEVE. That showed a rather impressive explosion from a small propane tank. Scaling that up to a propane railcar would be beyond impressive. Of course, getting a propane railcar to become a BLEVE is extremely difficult. It would take a great deal of heat over a long period of time to make it happen. It would be difficult to pull off, but a properly twisted person could come up with an appropriate method. For example…. Deliberate Propane Railcar BLEVE Two propane railcars are sitting on an isolated siding hooked together. A savvy terrorist places a small shaped charge device on the end of one railcar, on the end facing the second car. A properly placed shape charge will place a small diameter hole through the pressure wall of the rail car. Because there is no air inside the railcar, the propane will not ignite inside the car. Instead it will start flowing out of the car through the hole; very likely igniting as it passes over the melted metal on the edges of the whole. You now have a propane torch pointing directly at the end of the second propane rail car; much like the flame in the BLEVE video. Periodically, the pressure relief device on the second car will release some of the stored pressure in the car. If the valve is far enough away from the first car it might not immediately ignite. That would result in a small cloud of propane gas that would eventually reach the torch and cause an impressive but ineffective explosion. Sooner or later the metal wall under the torch will weaken and there will be a catastrophic failure of the railcar wall and there will be a very large explosion and the overpressure developed will create a large damage footprint. Just how large will depend on the amount of propane left in the car when the car wall failed. A second explosion will follow very shortly afterwards because of the blast effects on the first railcar will cause a catastrophic failure of that already damaged car. A prompt emergency response could prevent the BLEVE by applying copious amounts of water to the second car. Trained fire fighters would probably not try to put out the torch; as a safety measure they would let it continue to burn until the propane was consumed. As long as they kept the car walls cool enough to prevent the catastrophic failure of the second car, the fire would be visually impressive and expensive but not overly dangerous. Multiple BLEVE Incident You can make things even worse by putting a third propane railcar on the far side of the target car. If that second railcar becomes a BLEVE, it is likely that large portions of metal from the first explosion will fly into the third car and create a catastrophic failure of that car. The gas cloud explosion from the third car will be much larger because very little of the propane will have been lost through pressure venting. A fourth car in line would be a little less likely to be catastrophically damaged; at some point the chain reaction of detonations would no longer continue. With a slightly larger string of propane cars a creative terrorist could place a second shaped charge device on the last rail car in the string, pointing back towards the center of the chain. If everything works perfectly the two strings of explosions will meet in the middle. With each explosion the damage zone will expand because structures that were slightly damaged in the initial explosion would receive additional damage with each subsequent explosion. With a one-hundred car train of propane a really efficient and demented terrorist would set off multiple initial shape charge ignition points, as many as could be managed. As many as possible would be placed at points where it would be difficult to get fire fighting equipment. This would force the incident commander to surrender the attempt to contain the fires and concentrate on evacuating an extensive blast zone. A string of 100 cars, parked end to end would create a very large effective blast zone. If the targeted cars were in an industrial park, there would almost certainly be secondary fires and release of toxic chemical caused by the explosions. Security Requirements Because of the way that the freight rail security rules were written, TSA would have no authority to direct security measures for a railcar storage facility that contained even as many a 100 propane railcars (or other equally flammable materials). The CFATS regulations would probably be the only way that the federal government could mandate security rules. I know, I said that the CFATS preamble said that DHS would not be regulating rail facilities, but the Assistant Secretary still does have the authority {49 CFR §27.200(b)(1)} to require any facility to complete a Top Screen by simply sending a registered letter or posting a notice in the Federal Register. The legislation currently under consideration in the House would confer similar authority on the Secretary. While we don’t know how the CSAT tool determines which facilities are high-risk, I think that it can be reasonably assumed that a Top Screen filed for a facility storing 100 railcars worth of propane would be determined to be a high-risk facility almost anywhere in the country (in the middle of nowhere Montana might allow it to escape that designations). Again, I would guess that that much propane in one location would probably be a Tier 1 facility. Perhaps the company reviewing the proposal, Bechtel Jacobs, should consider the security implications as well as the safety aspects of the potential plan.


Anonymous said...

Well - if they didnt have the idea in their head before, they do now!! Sometimes I wonder about the wisdom of free speech!!

PJCoyle said...

For my reply to the comments made by Anonymous see:

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