SUPPLEMENTARY INFORMATION:

Abbreviations and Terms Used in This Document

ASP—Alternative Security Program

CFATS—Chemical Facility Anti-Terrorism Standards

COI—Chemical(s) of Interest

CVI—Chemical-Terrorism Vulnerability Information

DHS—Department of Homeland Security

EPA—Environmental Protection Agency

RMP—Risk Management Program

SSP—Site Security Plan

STQ—Screening Threshold Quantity

SVA—Security Vulnerability Assessment

VCE—Vapor Cloud Explosion

I. Comments Invited

A. In General

DHS invites interested persons to submit written comments, data, or views. For each comment, please identify the document number and agency name for this notice. DHS encourages commenters to provide their names and addresses. You may submit comments and materials electronically or by mail as provided under the ADDRESSES section. DHS will file in the public docket all comments received by DHS, except for comments containing confidential information, sensitive information, or Chemical-terrorism Vulnerability Information (CVI) as defined in 6 CFR 27.400(b).

B. Handling of Confidential and Sensitive Information and Chemical-Terrorism Vulnerability Information (CVI)

Do not submit comments that include trade secrets, confidential commercial information, Chemical-terrorism Vulnerability Information (CVI) or other sensitive information to the public docket. Please submit such comments separate from other non-sensitive comments regarding this notice. Specifically, please mark any confidential or sensitive comments as containing such information and submit them by mail to the individual listed in the FOR FURTHER INFORMATION CONTACT section. Any comments containing CVI should be marked and handled in accordance with the requirements of 6 CFR 27.400(f).

DHS will not place any confidential or sensitive comments in the public docket; rather, DHS will handle them in accordance with applicable safeguards and restrictions on access. See, e.g., 6 CFR 27.400. See also the DHS CVI Procedural Manual (“Safeguarding Information Designated as CVI,” September 2008, located on the DHS Web site at http://www.dhs.gov/​chemicalsecurity). DHS will hold any such comments in a separate file to which the public does not have access, and place a note in the public docket that DHS has received such materials from the commenter.

C. Reviewing Comments in the Docket

For access to the docket to read the public comments received and relevant background documents referred to in this notice, go to http://www.regulations.gov.

II. Background

A. Chemical Facility Security Rulemaking

Section 550 of the Homeland Security Appropriations Act of 2007 (Pub. L. 109-295, Oct. 2006) required the Department to issue, within six months, interim final regulations for the security of chemical facilities that, “in the Secretary's discretion, present high levels of security risk.” Under that authority, the Department promulgated the Chemical Facility Anti-Terrorism Standards, 6 CFR part 27 (CFATS), on April 9, 2007. See72 FR 17688.

The CFATS interim final rule sought public comment on Appendix A, a tentative list of over 300 chemicals of interest (COI) with the potential to create significant human life or health consequences if released, stolen or, diverted, or sabotaged. Section 27.200(b)(2) of the CFATS regulation requires any chemical facility that possesses any COI at or above the applicable screening threshold quantity (STQ) specified in Appendix A to complete and submit an online data collection (the Top-Screen) to DHS. The Department uses the facility's Top-Screen and, where applicable, other available information to perform a preliminary assessment of the facility's capacity to cause significant adverse consequences if targeted for a terrorist attack.^[1] DHS uses that preliminary ( printed page 2446) consequence assessment to make an initial high-risk determination for the facility. See6 CFR 27.200-27.210.

The Department assigns each facility that is initially determined to be high-risk to a preliminary risk-based tier level (Tiers 1-4, with Tier 1 representing the highest risk) and notifies the facility that it must submit a Security Vulnerability Assessment (SVA) to DHS. The Department uses the SVA to make a final high-risk and tiering determination. Only those facilities that are finally determined to be high-risk are subject to the full scope of the regulations and required to submit, for DHS approval, Site Security Plans (SSPs) or Alternative Security Programs (ASPs) that satisfy the risk-based performance standards specified in the CFATS regulations. See6 CFR 27.220-27.225.

DHS issued the final Appendix A on November 20, 2007. See72 FR 65396. The November 2007 rule clarified that chemicals of interest listed in Appendix A due to potential risks related to “release” are classified as Release-Explosives, Release-Flammables, or Release-Toxics, according to the type of potential harm they may cause. See72 FR 65397. In response to comments on the tentative Appendix A, DHS also added provisions to CFATS to clarify under what circumstances ^[2] and in what manner facilities must calculate the quantities of certain types of COI under Appendix A to determine if they are required to submit Top-Screens. See72 FR 65397-65398.

B. Special Provisions for Counting COI in Mixtures

Among other clarifications made in November 2007, DHS added § 27.203, which instructs facilities on when and how to calculate the STQ for certain types of chemicals of interest. With respect to chemicals in gasoline, § 27.203(b)(1)(v) requires facilities to count release-flammable COI (such as butane and pentane) contained

in gasoline, diesel, kerosene or jet fuel (including fuels that have flammability hazard ratings of 1,2, 3 or 4, as determined by using National Fire Protection Association (NFPA) [standard] 704 * * * ) stored in aboveground tank farms, including tank farms that are part of pipeline systems.

In response to comments requesting that DHS clarify whether and how facilities should count COI in mixtures when calculating whether a facility meets or exceeds the applicable STQ under Appendix A, the November 2007 rule also added § 27.204. That section specifies how to calculate the amount of Release-Toxic, Release-Flammable and Release-Explosive COI (as well as Theft-COI) in chemical mixtures. See72 FR 65399, 65416. In particular, § 27.204(a)(2) (the “flammable mixtures rule”) clarified how to calculate the quantity of Release-Flammable COI contained in chemical mixtures, including gasoline ^[3] and the other fuels specified in § 27.203(b)(1)(v), for purposes of Appendix A.

The CFATS flammable mixtures rule generally parallels the rules previously adopted by the U.S. Environmental Protection Agency (EPA) under the Clean Air Act's Risk Management Program (RMP) for counting—or excluding—flammable chemicals contained in mixtures that may be inadvertently or accidentally released.^[4] See72 FR 65402. As explained in the preamble to the November 2007 rule, however, given the different purposes, scope, and applicability of CFATS and the EPA RMP rules, there are several important differences between the CFATS and RMP mixture regulations. See72 FR 65398-65399, 65401-65402.

One such difference is that the CFATS flammable mixtures rule requires that Release-Flammable COI (such as butane or pentane) contained in gasoline (and other fuels specified in § 27.203(b)(1)(v)) must be counted under Appendix A, even though EPA does not count the flammable chemicals in gasoline under the terms of the RMP “mixtures rule,” 42 CFR 68.115(b)(2).^[5] See72 FR 65399 and n. 8. The November 2007 rule explained that, while EPA's RMP rules are premised solely on accidental releases of chemicals, the COI in these flammable mixtures, including gasoline, should be counted under Appendix A because of the potential consequences to human life or health of an intentional terrorist attack. See72 FR 65399.

C. Implementation of CFATS

Over 36,000 facilities have submitted Top-Screens to DHS and about 6,500 of those facilities were preliminarily determined by DHS to be high-risk and required to submit SVAs. DHS is now in the process of notifying those facilities that, based on review of their SVAs, DHS has finally determined to be high-risk and thus required to submit SSPs. On June 29, 2009, DHS issued final high-risk notifications to 10 aboveground gasoline storage tank facilities ( i.e. , terminals).^[6] Subsequently, DHS extended the SSP due dates for those facilities to allow the Department to coordinate further actions regarding terminals as a group. This extension is indefinite, pending the Department's consideration of certain technical issues and questions raised during the initial high-risk determination process for those facilities, as discussed below.

III. Issues Raised by the Gasoline Terminals Industry

A. Petition From International Liquid Terminals Association

Soon after promulgation of the November 2007 Appendix A final rule, several trade associations representing gasoline terminals raised both technical and procedural issues related to the applicability of Appendix A and the Top-Screen requirement to those facilities. Procedurally, those associations claimed that DHS did not provide advance notice and opportunity to comment on the provisions of §§ 27.203 and 27.204 related to aboveground fuel storage facilities that DHS added to CFATS in November 2007. Technically, the industry associations claimed that DHS had overestimated the potential consequences of a terrorist attack on gasoline terminals by relying on a model that calculates the impacts of a “vapor cloud explosion” from release of flammable liquids from aboveground storage tanks, which the industry asserted is unrealistic for gasoline terminals.

On May 13, 2009, the International Liquid Terminals Association (ILTA) submitted a petition to DHS under the Administrative Procedure Act requesting that DHS exempt gasoline ( printed page 2447) from CFATS and remove all references to gasoline terminals from § 27.203(b)(1)(v) and the CFATS flammable mixtures rule (§ 27.204(a)(2)).^[7] Through this notice, DHS invites comments on certain technical issues related to the applicability of CFATS to gasoline terminals.

B. Modeling of Potential Consequences From Aboveground Gasoline Storage Tanks

In deciding to add provisions to CFATS for counting chemicals of interest in aboveground gasoline storage tanks, DHS considered several possible methods for modeling the potential consequences of terrorist incidents directed at such facilities— i.e., the vapor cloud explosion (VCE) model and the “pool fire” model.

1. Modified VCE Model for Gasoline Terminals

In essence, a VCE model calculates the maximum distance at which a vapor cloud produced by release of flammable chemicals would be harmful or lethal to persons in or near the cloud (the “distance to endpoint”), based on the amount of flammable liquid chemical available, the estimated amount of the liquid that would convert to vapor, and the distance the vapor cloud could spread before becoming too “lean” to explode when exposed to an ignition source.

Since EPA had already developed a VCE model for estimating the consequences of accidental releases of flammable chemicals, including flammable mixtures, under the RMP regulations, DHS used the EPA VCE model as a starting point for modeling potential VCE consequences for all Release-Flammable COIs, including those at gasoline terminals.^[8] DHS modified the EPA VCE model, however, to account for certain differences between gasoline and other flammable liquids mixtures, as explained below. DHS believes the modified VCE model reflects a plausible worst-case scenario for terminals and is an appropriate tool for assessing the potential consequences of a terrorist attack against gasoline terminals.

Specifically, DHS refined the EPA VCE model to provide an even more plausible estimate of the potential consequences of a terrorist attack on gasoline terminals in particular. While EPA's VCE model assumes that (up to) ten percent of a given amount of a flammable liquid will participate in the explosion (the “yield factor”), DHS assumes that only one percent of gasoline will participate, based on gasoline's combustion properties and its storage at ambient conditions.^[9] This modification results in a reduction of the potential consequences calculated by the model, as compared to EPA's model, and appears to be consistent with the consequences from prior vapor cloud explosions involving gasoline, as discussed below. Therefore, the modified VCE model allows DHS to reasonably estimate the number of plausible worst-case casualties resulting from a successful attack on a gasoline terminal.

DHS understands that the formation of a gasoline vapor cloud with the potential to cause significant harm to human life and health requires that a number of natural and man-made circumstances combine in a certain way, and that accidental gasoline vapor cloud explosions are therefore uncommon. DHS has determined, however, that those necessary conditions are more likely to exist in the event of an intentional terrorist incident than in the context of an accident, and thus, that it is reasonable and within the Secretary's discretion under Section 550 to apply the modified VCE model to gasoline terminals. See generally72 FR 65399.

For example, in 2005 (long after EPA excluded gasoline from the RMP rule, see n. 5, supra), a vapor cloud explosion resulting from an unintentional overflow of a gasoline storage tank at the Buncefield Oil Storage Depot in Hertfordshire, UK caused significant injuries and other damage. Several gasoline storage trade associations have asserted that the combination of specific circumstances resulting in the Buncefield incident— e.g., accidental but prolonged and undetected overflow of the tank, failure of detection devices, congestion from nearby obstacles, weather conditions favoring accumulation rather than dispersal of the vapor cloud ^[10] —are so rare that DHS should disregard the possibility of such explosions at gasoline terminals.^[11]

DHS has concluded, however, that a terrorist seeking to cause such an explosion could target a facility where the necessary physical conditions exist (or are likely to occur at some point in time). In order to maximize the consequences of the explosion, such a terrorist could attempt to cause gasoline to leak or overflow from the targeted tank(s) in such a way as to make formation of a vapor cloud more likely than it would be in an accident like the Buncefield explosion.

Nonetheless, DHS invites public comment on the modified VCE model and on any alternatives to the specific modification made by DHS to the yield factor in the model.

2. “Pool Fire” Models

DHS considered other options for evaluating the potential consequences of a release from such facilities. Specifically, DHS considered an existing model that calculates the potential consequences from the radiated heat of a “pool fire” caused by ignition of liquid gasoline suddenly released from one or more aboveground tanks, but that implicitly assumes the pool fire is confined within dikes or other secondary containment surrounding the tank(s).^[12] The gasoline industry asserts that this “contained pool fire” scenario is more realistic for terrorist incidents involving gasoline terminals ( e.g., attacks using explosive devices or weapons) than the VCE scenario. The industry also asserts that the potential consequences of such contained pool fires do not warrant subjecting terminals to any CFATS requirements.

DHS did not rely on the “contained pool fire” scenario, however, because any model that assumes the effectiveness of secondary containment does not represent a plausible, worst-case terrorist scenario, since an adversary seeking to maximize the consequences of attacking a terminal would also attempt to breach the secondary containment.^[13]

( printed page 2448)

DHS is currently considering, however, and seeks comments on, whether it is feasible to refine existing models or develop a new model for uncontained pool fires ( i.e., where the contents of one or more gasoline storage tanks escape from secondary containment),^[14] so that such a model could be used for future consequence assessments for gasoline terminals—in lieu of or in addition to the modified VCE model.

IV. Issues for Commenters

Comments that will provide the most assistance to DHS should address the following issues and questions. Commenters should include explanations and relevant supporting materials with their comments whenever possible.

a. Comments on the inclusion of 6 CFR 27.203(b)(1)(v) (counting of Release-COI in gasoline, diesel, kerosene, or jet fuel in aboveground storage tanks) and 6 CFR 27.204(a)(2) (the flammable mixtures rule), as they apply to gasoline terminals.

b. Comments on the applicability of the modified VCE model to gasoline terminals, including: Whether the reduction of the vapor yield for gasoline from ten percent (as in EPA's VCE model) to one percent reasonably reflects the potential consequences for a vapor cloud explosion from gasoline (as compared to other liquid flammable chemicals); and whether a different yield factor adjustment might better reflect the potential consequences for a vapor cloud explosion from gasoline.

c. Comments on whether a reasonable model exists or should be developed for future use that would allow DHS to estimate the plausible worst-case consequences of an uncontained pool fire resulting from a successful attack on gasoline terminals.