Wednesday, November 30, 2011

Large Propane Tanks – Security Issues

I received an interesting email from a web searcher, David Giacalone, who found my blog post on protection of large propane tanks from October 2007. He was looking for information supporting his active opposition of to the installation (completed) of a large (30,000 gal) propane tank in a local neighborhood. The current stage of the fight includes opposing the issuance of a ‘Certificate of Occupancy’, typically the last regulatory hurdle before tanks such as this are filled.

I won’t go into all of the details of the basis of David’s opposition to this propane storage tank; he has an extensive blog post on the matter. And I certainly don’t want to get involved in a discussion about local zoning ordinances or even State fire codes (okay, sometimes I do, but not in this case). There are, however a couple of issues that do bear discussion on this blog; the first dealing with propane limits for COI determination and the second on when applications for Top Screens should be made. Finally there is the issue of adequate security for such tanks.

Propane COI

Propane is a curious DHS Chemical of Interest (COI) for a number of reasons. First as a flammable release COI it has a much larger Screening Threshold Quantity (STQ) than other similar COI (I’ll forgo that standard rant for now); set at 60,000 lbs vs the normal 10,000 lbs. This was specifically done to avoid coverage of a huge number propane storage tanks; likely outstripping the number of other CFATS covered facilities combined.

The other problem is that people don’t normally refer to ‘pounds’ of propane, it is usually referred to in ‘gallons’. This causes some confusion because the number of pounds of propane in a gallon is dependent on the pressure in the tank; ranging from 2.001 kg/m3 @ 1013 mbar to 581 kg/m3 as a liquid (high pressure).

According to David’s blog, the company that owns this tank contacted DHS (presumably ISCD) about whether this tank would be covered under CFATS and was told no. David later contacted the ISCD Help Desk and they confirmed that a 30,000 gallon tank would hold considerably more than 60,000 lbs and would require a Top Screen submission. I would assume that the discrepancy between the two DHS responses was due to the confusion between gallons and pounds. That discrepancy has apparently been resolved.

Finally we must remember that there are two different security issues with a release of propane, fire and explosions. A non-catastrophic rupture of a propane tank (a reasonable size hole) results in a high-pressure jet of flammable gas coming out of the hole. Nearby ignition sources or even internal static electric discharges will cause this jet to ignite and produce a visually stunning torch. As long as there are no combustible materials within reach of that torch, this is simply (only a slight overstatement) a dangerous yet controllable situation. The fire is typically allowed to consume all of the available propane while keeping the tank is kept cool enough with water sprays that it doesn’t catastrophically fail.

An explosion is much more difficult to cause, but it would have much further reaching consequences. A significant portion of the contents of the tank must be released into the atmosphere under the proper environmental conditions without creating the torch described above. This is required to create the gas cloud necessary for a fuel-air explosion. You need a large enough release to create a gas cloud of sufficient size to create an explosion large enough to create a larger secondary explosion when the remainder of the tank’s content is released catastrophically.

In short, you have to be really skilled or very lucky (from the attacker’s point of view) to cause a propane tank explosion. They do happen from accidental releases from time-to-time, but they really are very rare. There are just too many things that have to go right (wrong?) for the tank to explode.

DHS hasn’t discussed this in public, for obvious reasons, but one would assume that they are more concerned with the latter release situation unless there are significant stores of other COI that could be affected by the torch effect. A propane torch, for example, would be an excellent way to force a catastrophic chlorine release.

When to File a Top-Screen

The CFATS regulations are quite clear. Once a facility has one or more COI on site at or above the STQ for that COI, they have 60-days to file a Top Screen submission via the on-line Chemical Security Assessment Tool (CSAT). Only after that Top Screen is submitted can DHS make an interim determination whether or not that facility will be considered a high-risk chemical facility that is covered under the CFATS program.

From a regulatory perspective this certainly makes a great deal of sense; from a business perspective, not so much. The costs associated with the security requirements for a CFATS covered facility could have a serious impact on the profitability of a company. It would certainly be nice to know if those costs would be required in advance of constructing or upgrading the facility.

Even if one were to call ISCD and ask about the potential coverage of a new facility or even a facility adding a COI to their inventory, the most that the Help Desk, or even the Director, could really tell one is whether or not a Top Screen would be required. And as I described above, that is really cut and dried.

The evaluation of the Top Screen is a complex undertaking, looking at both the COI, the facility in which it is used and the surrounding community. That is one of the reasons that the Top Screen Tool is such a lengthy questionnaire.

Now I suppose that a company could register with DHS and submit a Top Screen for a planned facility; there is nothing in the regulation that would prohibit that. There would be some complications if the facility decided not to go ahead with their COI plans, but those could be worked out (Chime in anytime ISCD if I’m getting anything wrong here). The results from the Top Screen would tell the company that the facility would be covered by CFATS, but it wouldn’t tell them what security measures would be required. As the current CFATS covered facilities are discovering that it is still a long, long road to travel before the security requirements (and resultant costs) become really clear.

As a final comment on Top Screens, I would like to note and suggest that it would certainly be helpful to both the business community and ISCD if there were provisions for filing prospective Top Screens. The form and evaluation would be essentially the same, there would just be the clear understanding that the COI in question was not yet (and may not ever be) on site at the facility.

Propane Tank Security

Now we finally get to the meat of the reason that David contacted me in the first place. What is adequate security for a large propane tank? David sent me a couple of pictures of the tank currently in place in Duanesburg, NY (those and others are posted on his blog) and the tank in question clearly does not meet the security requirements set forth in the Risk-Based Performance Standards guidance document for a CFATS covered facility.

NOTE: The governing phrase in that last sentence is “for a CFATS covered facility”. Remember, CFATS is a counter-terrorism program. If the facility is not at high-risk of a potential terrorist attack (ie: not covered under CFATS), then the security processes and equipment required for a CFATS facility are not necessary. The remaining discussion only applies to a CFATS covered facility.

There are no perimeter barriers, entrance gates, etc protecting the tank. The few fences around auxiliary equipment are too short to be an impediment to any non-geriatric attackers. There is nothing here to ‘deter, detect or delay’ a terrorist attack on this tank.

I am certainly not going to try to engineer a security system for a propane tank (there are more than enough security integrators around willing and more experienced than I to handle that task), but clearly a barrier fence with controlled entrances is a primary requirement. Given the nature of the ‘target’ some sort of protection against vehicle borne improvised explosive devices (VBIED) needs to be in place. Some sort of protection against direct fire weapons would also be a good thing to have (though let’s be honest, a bullet from standard hunting rifle or AK47 is probably not going to penetrate the steel shell of a high-pressure storage-tank) though just hiding the tank behind a screen from the road would probably suffice.

There is, of course, much more that would go into such a security program; see the lengthy RBPS guidance document. More importantly, contact a good security consultant; one that has worked with this specific DHS program. And then wend your way through the CFATS gauntlet.


David Giacalone said...

Thank you very much, Patrick, for a thoughtful and comprehensive discussion of the Duanesburg tank and propane security. I will keep you posted as the tale unfolds.

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