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[Federal Register Volume 77, Number 131 (Monday, July 9, 2012)]
[Proposed Rules]
[Pages 40318-40319]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-16692]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[EPA-HQ-SFUND-2011-0647; FRL-9697-5]
RIN 2050-AD75

Availability of Addendum to Documentation Supporting the Proposal 
of the Leeds Metal Site to the National Priorities List

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule; notice of data availability.

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SUMMARY: This Notice provides an opportunity to comment on the EPA's 
revised Hazard Ranking System (HRS) scoring for the Leeds Metal site in 
Leeds, Maine. The site was proposed to the National Priorities List 
(NPL) on September 16, 2011.

DATES: Comments must be submitted (postmarked) on or before August 8, 
2012.

ADDRESSES: Submit your comments, identified by Docket number EPA-HQ-
SFUND-2011-0647, by one of the following methods:
    www.regulations.gov: Follow the online instructions for 
submitting comments.
     Email: superfund.docket@epa.gov.
     Mail: Mail comments (no facsimiles or tapes) to Docket 
Coordinator, Headquarters; U.S. Environmental Protection Agency; CERCLA 
Docket Office; (Mail Code 5305T); 1200 Pennsylvania Avenue NW.; 
Washington, DC 20460.
     Hand Delivery or Express Mail: Send comments (no 
facsimiles or tapes) to Docket Coordinator, Headquarters; U.S. 
Environmental Protection Agency; CERCLA Docket Office; 1301 
Constitution Avenue NW.; EPA West, Room 3334, Washington, DC 20004. 
Such deliveries are accepted only during the Docket's normal hours of 
operation (8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
Federal holidays).
    Instructions: Direct your comments to Docket number EPA-HQ-SFUND-
2011-0647. The EPA's policy is that all comments received will be 
included in the public Docket without change and may be made available 
online at www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through www.regulations.gov 
or email. The www.regulations.gov Web site is an ``anonymous access'' 
system; that means the EPA will not know your identity or contact 
information unless you provide it in the body of your comment. If you 
send an email comment directly to the EPA without going through 
www.regulations.gov, your email address will be automatically captured 
and included as part of the comment that is placed in the public Docket 
and made available on the Internet. If you submit an electronic 
comment, the EPA recommends that you include your name and other 
contact information in the body of your comment and with any disk or 
CD-ROM you submit. If the EPA cannot read your comment due to technical 
difficulties and cannot contact you for clarification, the EPA may not 
be able to consider your comment. Electronic files should avoid the use 
of special characters, any form of encryption, and be free of any 
defects or viruses.
    Docket: All documents in the docket are listed in the 
www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in www.regulations.gov or in hard copy at the EPA Headquarters CERCLA 
Docket Office, 1301 Constitution Avenue NW.; EPA West, Room 3334, 
Washington, DC 20004. The Public Reading Room is open from 8:30 a.m. to 
4:30 p.m., Monday through Friday, excluding legal holidays. The 
telephone number for the Public Reading Room is (202) 566-1744, and the 
telephone number for the EPA Headquarters CERCLA Docket Office is (202) 
566-0276. Comments must be submitted to the EPA Headquarters as 
detailed at the beginning of this preamble in the ``Addresses'' 
section. Please note that the mailing addresses differ according to 
method of delivery. There are two different addresses that depend on 
whether comments are sent by express mail or by postal mail.

FOR FURTHER INFORMATION CONTACT: Terry Jeng, phone: (703) 603-8852, 
email: jeng.terry@epa.gov, Site Assessment and Remedy Decisions Branch, 
Assessment and Remediation Division, Office of Superfund Remediation 
and Technology Innovation (Mail Code 5204P), U.S. Environmental 
Protection Agency, 1200 Pennsylvania Avenue NW., Washington, DC 20460.

[[Page 40319]]

SUPPLEMENTARY INFORMATION:

Site Scoring Information

    The Leeds Metal HRS site score at the time of proposal to the 
National Priorities List was based on an observed release to ground 
water of tetrachloroethylene (PCE) and trichloroethylene (TCE) 
attributable to waste piles and contaminated soil at the Leeds Metal 
facility resulting in a likelihood of release factor category value of 
550. The waste characteristics factor category value of 56 at proposal 
was based on a hazardous waste quantity for TCE of 10,000, a toxicity 
value for TCE of 10,000 and a mobility factor for TCE of 1. The TCE 
toxicity value was based on the most recent health effects data review 
by the EPA at the time of proposal (76 FR 57702, September 16, 2011).
    The targets factor category value was 176.4 at proposal based on 
populations relying on contaminated drinking water supplies with either 
PCE or TCE levels above HRS health-based benchmarks (i.e., Level I 
concentrations). Seven residential wells were documented to contain 
Level I concentrations of TCE based on the lowest benchmark value for 
TCE for ground water. One of these seven wells was also documented to 
contain Level I concentrations of PCE based on the lowest benchmark 
value for TCE for ground water. The lowest benchmark for TCE was the 
cancer slope screening concentration (0.21 [mu]g/L) and the lowest 
benchmark for PCE was also the cancer slope screening concentration 
(1.6 [mu]g/L) based on the most recent health effects data review by 
the EPA at the time of proposal. Seventeen residents were documented to 
drink the water from the seven wells with Level I concentrations. The 
likelihood of release, waste characteristics and targets factor 
category values resulted in a ground water migration pathway score of 
100.00 and an HRS site score of 50.00 at proposal (see 76 FR 57702, 
September 16, 2011).

Background on TCE and PCE Benchmarks and Toxicity Values

    Following the September 16, 2011, proposal of the Leeds Metal site 
to the National Priorities List, the toxicity and benchmark values for 
PCE and TCE used in HRS scoring were updated to reflect the EPA's most 
recent health effects evaluations on these two substances. The 
revisions for these two substances were made available to the public on 
March 31, 2012 (see http://www.epa.gov/superfund/sites/npl/hrsres/tools/scdm.htm). Among the factors that changed, which affect the 
toxicity and drinking water benchmarks, are the oral reference dose 
(RfD) and the oral cancer slope factors. Using the HRS methods for 
determining toxicity and benchmarks (see HRS Sections 2.4.1.1 and 
2.5.2), the toxicity for TCE has changed from 10,000 to 1,000, however 
the toxicity for PCE remains the same at 100. When recalculating the 
drinking water benchmarks for TCE, the lowest TCE benchmark value for 
drinking water remains based on the cancer slope screening 
concentrations; the recalculated TCE benchmark value changes from 0.21 
[mu]g/L to 1.0 [mu]g/L. The lowest drinking water benchmark for PCE 
changes from 1.6 [mu]g/L to 5.0 [mu]g/L.

Background on Targets Factor Category Value

    Based on the changes to the TCE and PCE benchmarks, two drinking 
water wells within the 4-mile target distance limit have TCE 
concentrations above its lowest benchmark and no well had PCE 
concentrations above its lowest benchmark. Thus, now only two wells and 
the population using these wells are considered Level I.
    The Leeds Metal site's potential population factor value has been 
updated to reflect those people utilizing drinking water not currently 
found to be contaminated due to this site, but that for HRS purposes 
are considered potentially threatened. The basic information supporting 
the calculation of this value was presented in Reference 11 which was 
available to the public at the time of NPL proposal; however, the 
factor value was not included in the HRS documentation record at that 
time. Populations utilizing either public or private water supplies 
have been incorporated into the HRS evaluation based on the information 
in Reference 11 to the HRS documentation record at proposal, which 
relied on 1990 and 2000 census data and 2009 population data from the 
State of Maine. The impact on eligibility of the site to qualify for 
the NPL has been confirmed based on the most current information, 
including updated census data (2010) and 2012 well use information.

New Benchmarks, Toxicities, Targets and Site Score

    Due to the revised toxicity values and the update to the evaluation 
of the potential targets, the likelihood of release factor category 
value remains 550, the same as at proposal; the waste characteristics 
factor category value, which was 100 at proposal, drops to 56 due to 
the changes in the Level I wells; the potential population factor 
value, the applicable targets factor category value, changes from 220 
to 176.4. As a result of these updates, the HRS ground water migration 
pathway score changes from 100.00 to 65.85; and the HRS site score 
changes from 50.00 to 32.92. The NPL listing decision is not changed by 
this updated information and scoring.
    The updated HRS scoring documentation is available in 
www.regulations.gov under docket number EPA-HQ-SFUND-2011-0647.

List of Subjects in 40 CFR 300

    Environmental protection, Air pollution control, Chemicals, 
Hazardous substances, Hazardous waste, Intergovernmental relations, 
Natural resources, Oil pollution, Penalties, Reporting and 
recordkeeping requirements, Superfund, Water pollution control, Water 
supply.

    Dated: June 29, 2012.
James E. Woolford,
Director, Office of Superfund Remediation and Technology Innovation.
[FR Doc. 2012-16692 Filed 7-6-12; 8:45 am]
BILLING CODE 6560-50-P
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