The Addition of a Subsurface Intrusion Component to the Hazard Ranking System

Docket ID: EPA-HQ-SFUND-2010-1086
Agency: Environmental Protection Agency (EPA)
The Hazard Ranking System (HRS), required by the Superfund statute, is the primary mechanism used by the EPA to assess the relative threat associated with actual or potential releases of hazardous substances. As a matter of agency policy, those sites that score 28.50 or greater under the HRS are eligible for inclusion on the National Priorities List (NPL). The NPL is intended primarily to guide the EPA in determining which sites warrant further investigation. A score of 28.50 does not represent a specified level of risk but is a cutoff point that serves as a screening-level indicator of the highest priority releases or threatened releases. The HRS includes four scoring pathways - ground water, surface water, air and soil exposure. Additional pathways have been identified as posing significant threats to human health and the environment that should be considered when evaluating sites for the NPL. One such pathway is subsurface intrusion. Subsurface intrusion occurs when contaminants are released, enter the subsurface environment and move into occupied structures (e.g., residences, workplaces and other buildings) as a gas, vapor or liquid. Over the past decade the EPA and state environmental programs have learned significantly more information regarding the risk that this pathway poses to human health. Historically, the EPA's Superfund program has responded to vapor intrusion contamination by two mechanisms: (1) through its emergency response program at sites not on the NPL, or (2) through sites placed on the NPL because of other pathway-related risks. In a May 2010 report, the Government Accountability Office (GAO) concluded that if vapor intrusion sites are not assessed and, if needed, listed on the NPL, some seriously contaminated hazardous waste sites with unacceptable human exposure may not otherwise be cleaned up. Thus, the EPA is considering adding a new screening component to the HRS that would allow sites with vapor intrusion contamination to be evaluated for placement on the NPL. This addition would enable the HRS to directly consider the human exposure to contaminants that enter building structures through the subsurface environment.
RIN: 2050-AG67
Impacts and Effects: None
CFR Citation: 40 CFR 300
Priority: Other Significant
UA and Regulatory Plan Information open glossary dialog  
Publication Period: Spring 2016
Agenda Stage of Rulemaking: Final Rule
Major Rule: No
Legal Authorities: 42 U.S.C. 9601
Legal Deadlines: None
Government Levels Affected: Federal, State, Local, Tribal
Federalism Implications: No
Unfunded Mandates: No
Requires Regulatory Flexibility Analysis: No
Small Entities Affected: No
International Impacts: No
Energy Effects: No
Included in Regulatory Plan: No
ActionDateFR Citation
Notice01/31/201176 FR 5370
NPRM02/29/201681 FR 10371
Final Rule01/00/2017
Docket Details open glossary dialog  
Related RINs: None
Related Dockets: None
Keyword(s): HRS, Vapor Intrusion, Subsurface Intrusion SsI
Type: Rulemaking
Location: HQ-SFUND

Primary Documents

View All  (2)
Comment Period Closed
Apr 29, 2016 11:59 PM ET
Proposed Rule
Posted: 02/29/2016
ID: EPA-HQ-SFUND-2010-1086-0062
Comment Period Closed
Apr 16, 2011 11:59 PM ET
Posted: 01/31/2011
ID: EPA-HQ-SFUND-2010-1086-0001

Supporting Documents

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Comments Not Accepted
Supporting & Related Material
Posted: 04/06/2016
ID: EPA-HQ-SFUND-2010-1086-0085
Comments Not Accepted
Supporting & Related Material
Posted: 03/18/2016
ID: EPA-HQ-SFUND-2010-1086-0083
Comments Not Accepted
Supporting & Related Material
Posted: 02/29/2016
ID: EPA-HQ-SFUND-2010-1086-0079


View All  (73)

Comments Received*
Regulatory Timeline
Pre Rule
Current Stage
Proposed Rule
Current Stage
Final Rule
Current Stage
Agency Contact
Terry Jeng
703 603-8852
5204P, 1200 Pennsylvania Avenue NW.
Washington, DC 20460
Brenda Cook
214 665-7436
214 665-6660 (Fax)
USEPA REGION 6, 1445 Ross Avenue, Suite 1200, 6SF
Dallas, TX 75202
*This count refers to the total comment/submissions received on this docket, as of 11:59 PM yesterday. Note: Agencies review all submissions, however some agencies may choose to redact, or withhold, certain submissions (or portions thereof) such as those containing private or proprietary information, inappropriate language, or duplicate/near duplicate examples of a mass-mail campaign. This can result in discrepancies between this count and those displayed when conducting searches on the Public Submission document type. For specific information about an agency’s public submission policy, refer to its website or the Federal Register document.