Friday, July 18, 2008

CSAT Tier Rankings

I received an interesting reader email the other day. The reader told me that he knew of at least a couple of oil refineries that had received a tier ranking from DHS and were surprised to find that they had been placed in Tier 4 (the lowest of the high-risk categories under CFATS). Since I was a ‘CFATS Expert’, he wanted to know if I had any idea of why they were rated so ‘low’. I thought this was an interesting question, so I told him I would take a stab at answering.


First, I am not an employee or even a consultant for DHS. I don’t have any inside information about the workings of CSAT other than what DHS has published publicly. So the conclusions that I arrive at here are based on my analysis of the available data. Flaws in that analysis are mine alone. I’ll try to identify my assumptions as I go to give everyone a fair chance at identifying those flaws.

Second, I do not know any of the details of the Top Screen submissions for these facilities. I do not even know the names of the facilities. Nor do I know, or really care, how my reader came to know the tier rankings of these facilities. In fact, to be perfectly honest, I have no way of even knowing if facts presented in his question are actual facts.

High-Risk Chemical Facilities

First we must remember that DHS was given authority to regulate chemical facilities that were at high-risk of terrorist attack. Specifically the Section 550 authorization provides that the CFATS regulations would "apply to chemical facilities that, in the discretion of the Secretary, present high levels of security risk".

This means that any facility that received a DHS notification letter requiring the facility to complete a Security Vulnerability Assessment (SVA) is preliminarily considered a high-risk chemical facility. All of the requirements of the CFATS regulations will apply to those facilities if they are confirmed as being a high-risk facility after the DHS review of the SVA.

All high-risk chemical facilities will be required to complete and submit site security plans that will address all of the security risks identified in the SVA. The standards that DHS will use in reviewing those plans for adequacy will be the same 18 risk-based performance standards (Section 27.230) for each of the high-risk chemical facilities.

The Purpose of Tiering

When DHS wrote the CFATS regulations they were faced with the dilemma of how to regulate an expected 8,000 high-risk chemical facilities with limited manpower and limited time (the regulations expire in three years from October 2006). When faced with a job of this size and limited resources available to DHS, one must prioritize.

The four risk-related tiers that DHS is placing the 7,006 high-risk chemical facilities into is a method of prioritizing the work that must be done. The tier 1 facilities are the highest risk facilities and thus the highest priority for DHS. This is reflected in the short time limit these facilities have to complete their SVA (90 days vs 180 days for tier 4 facilities).

DHS has been adamant in their refusal to discuss the details of the decision process that put into their tier. They believe that that level of risk analysis information could provide a well informed terrorist with too much information about the security processes at high-risk chemical facilities. I think, however, that we can assume that off-site consequence is a major component that goes into the decision to make a facility a tier 1 facility.

Off-Site Refinery Risks are Varied

Oil refineries are complex chemical manufacturing facilities. They take a mixture of organic liquids and solids known as crude oil and through a number of separation techniques and chemical reactions turn that material into a wide variety of chemical and fuel products. They use and produce a number of different hazardous chemicals. This means that there are a variety of risks associated with these facilities.

Flammable-Release Hazards

The most visible hazard to the public comes from flammable-release COI. While gasoline is a major product there are a number of flammable liquids and gasses that are stored and produced at these facilities. While fires associated with these chemicals can be a devastating issue for the refinery their off-site consequences are not that large, The large black clouds associated with hydrocarbon fires generally lift into the air quickly so the area of greatest toxic affects is fairly limited. Even when those clouds hug the ground most of the toxic affects are chronic rather than acute; they aggravate and cause long term medical conditions rather than killing immediately.

The worst potential off-site consequences are not associated with fires, but with explosions. The release of flammable gasses and very volatile flammable liquids produce large clouds of dangerous fuel-air mixtures. When ignited these mixtures produce huge explosions that can produce over-pressure effects over a large area.

It is easy to calculate the worst-case results from such an event. Assuming the total release of the largest storage tank containing such chemicals, there are mathematical formulas for calculating the area where the over-pressure affects are sufficient to produce significant damage. Comparing that area to the location of off-site facilities and people provide a way of measuring the off-site hazard.

Toxic Release Hazards

The wide variety of chemicals used and produced in the oil refinery includes a number of dangerous, toxic chemicals. The off-site consequences for these are most pronounced for toxic inhalation hazard (TIH) gases like hydrogen fluoride (HF). Again, those consequences can be calculated by comparing how far they can spread before they loose their acute toxic affect due to dilution with air. That area of spread can then be compared to the location of off-site personnel to determine the number at risk.

Economic Hazards

Anyone that has watched the news lately is aware that the disruption of even a single refinery’s output has an immediate affect on the price of gasoline. The tight supply of refined petrochemicals in the United States makes this inevitable for the foreseeable future. What additional effects would be seen from a successful terrorist attack on such facilities is more difficult to predict in detail, but we could assume that there would be an additional fear-premium added to fuel prices.

DHS did attempt to take economic costs into account in the Top Screen. There were a number of questions posed for refineries about market share and critical market served. I do not believe that DHS considered in their model the current fuel market volatility in this economic assessment.

Mitigating Factors

While DHS has not mentioned taking any sort of mitigating factors into account in their preliminary facility tiering decision, I think that it is possible that some special factors may have been taken into account with oil refineries.

First off most oil companies conduct operations in many parts of the world. Many of their facilities are located in areas where they have had to deal with attacks by a wide variety of bandits and terrorists. As such the large oil companies have a better handle on site security issues than almost any other player in the chemical facility arena. Thus DHS could expect that they would not require the same level of handholding during the CFATS process that most other facilities would.

Secondly, most of these facilities will already have completed an SVA using the API/NPRA SVA. This SVA methodology is already approved by the CCPS as being equivalent to their methodology. And DHS based much of their SVA on the CCPS method. This means that DHS would not expect to have many problems approving a Alternate Security Plan (ASP) based on API/NPRA SVA. Remember, only a Tier 4 facility can submit an ASP in lieu of an SVA.


Having considered all of this for a couple of days now, I could understand how an oil refinery could be legitimately assigned to a Tier 4 risk ranking by DHS. There would be more than a few caveats to that:

  • The 3-psi overpressure area for the worst-case flammable liquid/gas release would not include any significant (populated or economically/strategically important) off-site areas.
  • The distance of concern for the worst case release of any toxic release COI would not include any significant off-site areas.
  • The facility is owned/operated by a major oil company with experience operating in high-threat areas of the world.
  • DHS would have already contacted the refinery in question with a notice to increase their security profile due to the publicly avowed al Qaeda threats to the US oil infrastructure.

Remember, these facilities are still going to have to prepare a site security plan that will address all of the hazards identified in the SVA. More importantly, DHS can go back and raise their tier ranking once the SVA is submitted.

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