[Federal Register Volume 77, Number 55 (Wednesday, March 21, 2012)]
[Proposed Rules]
[Pages 16509-16512]
[FR Doc No: 2012-6676]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 70

[EPA-R09-OAR-2011-0955; FRL-9649-4]

Proposed Approval of Revision of Five California Clean Air Act
Title V Operating Permits Programs

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to approve revisions to the Operating Permits
(Title V) programs of the Monterey Bay Unified Air Pollution Control
District (MBUAPCD), San Luis Obispo County Air Pollution Control
District (SLOCAPCD), Santa Barbara County Air Pollution Control
District (SBCAPCD), South Coast Air Quality Management District
(SCAQMD), and Ventura County Air Pollution Control District (VCAPCD).
These program revisions will require sources with the potential to emit
(PTE)of greenhouse gas (GHG) above the thresholds in EPA's Tailoring
Rule that have not been previously subject to Title V for other reasons
to obtain a Title V permit. See ``Prevention of Significant
Deterioration and Title V Greenhouse Gas Tailoring Rule; Final Rule,''
(the Tailoring Rule), 75 FR 31514 (June 3, 2010). We are taking
comments on this proposal and plan to follow with a final action.

DATES: Any comments must arrive by April 20, 2012.

ADDRESSES: Submit comments, identified by docket number EPA-R09-OAR-
2011-0955, by one of the following methods:
    1. Federal eRulemaking Portal: www.regulations.gov. Follow the on-
line instructions.
    2. Email<EMAIL_ADDRESS>    3. Mail or deliver: Gerardo Rios (Air-3), U.S. Environmental
Protection Agency Region IX, 75 Hawthorne Street, San Francisco, CA
94105-3901.
    Instructions: All comments 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 Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. Information that you
consider CBI or otherwise protected should be clearly identified as
such and should not be submitted through www.regulations.gov or email.
www.regulations.gov is an ``anonymous access'' system, and EPA will not
know your identity or contact information unless you provide it in the
body of your comment. If you send email directly to EPA, your email
address will be automatically captured and included as part of the
public comment. If EPA cannot read your comment due to technical
difficulties and cannot contact you for clarification, 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: EPA has established a docket for this action under EPA-R09-
OAR-2011-0955. Generally, documents in the docket for this action are
available electronically at www.regulations.gov or in hard copy at EPA
Region IX, 75 Hawthorne Street, San Francisco, CA 94105. While all
documents are listed at www.regulations.gov, some information may be
publicly available only at the hard copy location (e.g., copyrighted
material, large maps, multi-volume reports), and some may not be
publicly available in either location (e.g., CBI). To inspect the hard
copy materials, please schedule an appointment during normal business
hours with the contact listed in the FOR FURTHER INFORMATION CONTACT
section.

FOR FURTHER INFORMATION CONTACT: Roger Kohn, EPA Region IX, (415) 972-
3973<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us'' and
``our'' refer to EPA.

Table of Contents

I. The State's Submittal
    A. What rules did the State submit?
II. The Part 70 Operating Permits Program
    A. What is the Part 70 operating permits program?
    B. How did EPA revise Part 70 to address Title V permitting of
GHG sources?

    C. What is the federal approval process for revisions to a Part
70 operating permits program?
III. EPA's Evaluation and Action
    A. How is EPA evaluating the rules?
    B. Do the rules meet the evaluation criteria?
    C. Public Comment and Proposed Action
IV. Statutory and Executive Order Reviews

I. The State's Submittal

 A. What rules did the State submit?

    Table 1 lists the rules addressed by this proposal with the dates
that they were adopted by the local air agencies and submitted by the
California Air Resources Board.

                                            Table 1--Submitted Rules
----------------------------------------------------------------------------------------------------------------
              Local agency                 Rule No.               Rule title              Adopted     Submitted
----------------------------------------------------------------------------------------------------------------
MBUAPCD................................         218    Title V: Federal Operating          11/17/10      11/7/11
                                                        Permits.
SLOCAPCD...............................         216    Federal Part 70 Operating            3/23/11      8/19/11
                                                        Permits.
SBCAPCD................................        1301    Part 70 Operating Permits--          1/20/11      4/21/11
                                                        General Information.
SCAQMD.................................        3000    General........................      11/5/10      11/5/10
                                               3001    Applicability..................
                                               3002    Requirements...................
                                               3003    Applications...................
                                               3005    Permit Revisions...............
                                               3006    Public Participation...........
VCAPCD.................................          33    Part 70 Permits--General.......      4/12/11      8/19/11
                                                 33.1  Part 70 Permits--Definitions...
----------------------------------------------------------------------------------------------------------------

II. The Part 70 Operating Permits Program

A. What is the Part 70 operating permits program?

    Title V of the Clean Air Act (CAA) Amendments of 1990 require all
states to develop an operating permits program that meets federal
criteria listed in 40 Code of Federal Regulations (CFR) Part 70. In
implementing this program, the states are to require certain sources of
air pollution to obtain permits that contain all applicable
requirements under the CAA. One purpose of the Part 70 operating
permits program (also known as the Title V program) is to improve
enforcement and compliance by issuing each source a single permit that
consolidates all of the applicable CAA requirements into a federally-
enforceable document. By consolidating all of the applicable
requirements for a facility into one document, the source, the public,
and the permitting authorities can more easily determine what CAA
requirements apply and how compliance with those requirements is
determined.

B. How did EPA revise Part 70 to address Title V permitting of GHG
sources?

    In the Tailoring Rule (75 FR 31514, June 3, 2010), we amended the
definition of ``major source'' in Part 70 by codifying EPA's
longstanding interpretation that applicability for a ``major stationary
source'' under CAA sections 501(2)(B) and 302(j) and 40 CFR 70.2 is
triggered by sources of pollutants ``subject to regulation.'' We also
added a definition of ``subject to regulation'' to clarify that this
phrase means a pollutant subject to either a provision in the CAA or a
regulation adopted by EPA under the CAA that requires actual control of
emissions of that pollutant and that has taken effect under the CAA.
Finally, to tailor the Title V program for GHGs, we also included a
second component within the definition of ``subject to regulation,''
specifying that GHGs are not subject to regulation for purposes of
defining a major source, unless as of July 1, 2011, the GHG emissions
are from a source emitting or having the potential to emit 100,000 tons
per year (tpy) of GHGs on a carbon dioxide equivalent (CO2e) basis. We
defined the term ``greenhouse gases'' with a cross-reference to the
definition in 40 CFR 86.1818-12(a). The combined effect of these Part
70 amendments is to revise the Title V program to require stationary
sources that have the potential to emit 100,000 tpy or more of GHGs on
a CO2e basis to obtain Title V permits, regardless of whether they are
subject to any CAA requirement to control their GHG emissions. The five
air districts whose Title V programs we are proposing to revise took
differing approaches to revising their Title V regulations to address
the Tailoring Rule's Title V requirements, depending on the structure
and content of their rules. In section III.B., we explain how the
districts' revised Title V regulations satisfy the new Title V GHG
criteria.

C. What is the federal approval process for revisions to a Part 70
operating permits program?

    In order for state regulations to be approved as part of the
federally-enforceable Title V operating permits program, states must
formally adopt regulations consistent with state and Federal
requirements. This process generally includes a public notice, public
hearing, public comment period, and a formal adoption by a state-
authorized rulemaking body.
    Once a state rule, regulation, or control strategy is adopted, the
state submits it to us for inclusion into its approved operating
permits program. We must provide public notice and seek additional
public comment regarding the proposed Federal action on the state
submission. If adverse comments are received, they must be addressed
prior to any final Federal action by us.
    All state regulations and supporting information approved by EPA
under section 502 of the CAA, including revisions to the state program,
are included in the Federally-approved operating permits program.
Records of such actions are maintained in the CFR at Title 40, part 70,
appendix A, entitled ``Approval Status of State and Local Operating
Permits Programs.''

III. EPA's Evaluation and Action

A. How is EPA evaluating the rules?

    The relevant statutory provisions for our review of the submitted
rules include 40 CFR Part 70, as amended by the June 3, 2010 Tailoring
Rule.

B. Do the rules meet the evaluation criteria?

    We have reviewed the five districts' revised Title V rules in
accordance with the rule evaluation criteria described above. A
discussion for each District is provided below. EPA is proposing to
find that each district's submittal correctly implements the changes in
Title V applicability required by the Tailoring Rule.

    MBUAPCD revised Rule 218 (Title V: Federal Operating Permits) to
satisfy the Tailoring Rule requirements. The District revised the
definition of ``Major Source'' in section 2.18.5 of the rule to include
sources that, as of July 1, 2010, emit or have the potential to emit
``100,000 tpy or more of carbon dioxide equivalent (CO2e) greenhouse
gas emissions and directly emit, or have the potential to emit, 100
tons per year (tpy) or more of any greenhouse gas,'' as required by the
Tailoring Rule. The District also revised Section 1.3 of the rule to
exempt sources that limit their PTE of GHG emissions to less than
100,000 tpy of CO2e greenhouse gas emissions, and to exclude greenhouse
gases from the exemption for sources that limit their PTE to less than
100 tpy of any air pollutant. The District added new definitions for
``Greenhouse Gases'' and ``Carbon Dioxide Equivalent Emissions''.
Instead of using a cross-reference to 40 CFR 86.1818-12(a), as EPA does
in the Tailoring Rule, MBUAPCD has provided a specific definition of
Greenhouse Gases in its rule, which is consistent with the EPA
definition. The District's definition of ``Carbon Dioxide Equivalent
Emissions'' incorporates the Global Warming Potential values that EPA
lists in Table A-1 to Subpart A of 40 CFR Part 98, EPA's Mandatory
Greenhouse Gas Reporting regulation. All of these changes, which are
the only changes that the District made to Rule 218, are consistent
with the requirements of the Tailoring Rule. We note that the
applicability date of July 1, 2010 is one year earlier than required by
the Tailoring Rule. This had no practical effect in the District
because there are no sources newly subject to Title V based solely on
being classified a major source for GHG emissions.
    SLOAPCD added a new provision to the Applicability section of Rule
216 (Federal Part 70 Permits). The new provision, in paragraph
216.B.2., requires sources that emit GHG in amounts ``equal to or
exceeding the thresholds specified in 40 CFR 70.2 in effect August 2,
2010'' to apply for a title V permit. The District also added a new
provision to the definition of ``Air Pollutant.'' The new provision, in
paragraph 216.C.4.f., adds ``Greenhouse gases that are `subject to
regulation' as defined in 40 CFR 70.2 in effect August 2, 2010'' to the
list of the air pollutants defined in the rule. These cross-references
to 40 CFR 70.2 means that the District's approach to tailoring the
applicability of its Title V program for GHG sources is identical to
EPA's. We are proposing to approve these revisions to SLOAPCD's title V
program because they are consistent with EPA's approach to Title V
applicability for GHG sources in the Tailoring Rule.
    SBCAPCD revised Rule 1301 (General Information), which is one of
five rules that comprise the District's Regulation XIII (Part 70
Operating Permit Program), by adding a cross-reference to 40 CFR 70.2.
Specifically, the District amended the definition of ``Part 70 Source''
in section 1301.C. by adding a new provision that makes sources with
the potential to emit ``greenhouse gases that are `subject to
regulation' as defined in 40 CFR 70.2 in effect August 2, 2010''
subject to Title V. This cross-reference to the 40 CFR 70.2 definition
of ``subject to regulation'' means that the District's approach to
tailoring the applicability of its Title V program to GHG sources is
identical to EPA's, and therefore approvable.
    In addition to the GHG-related rule changes adopted on January 20,
2011, SBCAPCD had previously revised the definition of ``stationary
source'' in Rule 1301 to reduce the area in which marine vessels
associated with a stationary source must account for their emissions.
Rule 1301 now limits the geographic area of emissions liability to
``California Coastal Waters'' (as defined in Rule 1301) adjacent to the
District, and excludes areas adjacent to the neighboring counties of
San Luis Obispo and Ventura. We are proposing to approve this change,
which is consistent with the District's jurisdiction in Santa Barbara
County.
    SCAQMD addressed the Tailoring Rule requirements by revising six of
the seven rules that comprise Regulation XXX (Title V Permits).
Specifically, SCAQMD revised Rule 3000 (General) to add definitions of
``Carbon Dioxide Equivalent'', ``Global Warming Potential'', and
``Greenhouse Gas.'' SCAQMD also revised Rule 3001 (Applicability) to
require that any facility that, as of July 1, 2011, has the potential
to emit 100,000 tpy or more of GHG on a CO2e basis and a
potential to emit more than 100 tpy of any GHG on a mass basis apply
for a Title V permit within 180 days. SCAQMD provided a specific
definition of GHG in Rule 3000 which is consistent with the EPA
definition. The District's definition of ``CO2 equivalent''
is based on the same Global Warming Potential values that EPA lists in
Table A-1 to Subpart A of 40 CFR Part 98, EPA's Mandatory Greenhouse
Gas Reporting regulation. SCAQMD's definition of ``Global Warming
Potential'' uses the same language as EPA's definition in 40 CFR
Section 98.6. Finally, SCAQMD revised Rule 3003 (Applications), Rule
3005 (Permit Revisions), and Rule 3006 (Public Participation), to make
the cross references to Rule 3000 within those rules consistent with
the revised numbering sequence in that rule. Since the District's Title
V program changes are consistent with EPA's approach to Title V in the
Tailoring Rule, we are proposing to approve them as a revision to
SCAQMD's Title V program.
    VCAPCD addressed the applicability of title V permitting for major
GHG sources by revising the applicability provisions of Rule 33 (Part
70 Permits--General). Specifically, the District revised subsection
33.B.1., which requires stationary sources with a PTE of 100 tpy or
more of any regulated air pollutant to obtain a title V permit. VCAPCD
added language to this provision to make it applicable to sources that
emit greenhouse gases, effective July 1, 2011, if a source also has a
PTE of 100,000 tons per year or more on a CO2 equivalent
basis.
    In addition the District added a new definition of ``CO2
Equivalent (CO2e)'' to Rule 33.1 (Part 70 Permits--
Definitions) that is based on EPA's definition of ``tpy CO2
equivalent emissions'' in 40 CFR 70.2, and refers to the Global Warming
Potentials that appear in Table 1 of Rule 2 (Definitions). (Rule 2 has
been submitted to EPA for approval into the Ventura County portion of
the California State Implementation Plan. We will take action on that
rule in a separate rulemaking.) We are approving the District's
definition because, while it is not identical to the 70.2 definition,
it is sufficiently similar to, and fully consistent with, our
definition. The District also revised two definitions in Rule 33.1. The
definition of ``regulated air pollutant'' now includes greenhouse gases
if the source has a potential to emit of 100,000 tons per year or more
CO2 equivalent emissions. The definition of ``Insignificant
Activity'' now excludes greenhouse gases from the emission level of 2
tpy of any regulated pollutant that otherwise qualifies an activity as
insignificant.
    VCAPCD also made one revision that is unrelated to GHG. The
District revised the definition of ``Federally-Enforceable
Requirement'' in Rule 33.1. The District added language to Subparagraph
33.1.12.a, which lists Title I requirements of the CAA that are
federally enforceable, to clarify that federally enforceable Title I
requirements are ``not limited to'' the requirements listed in the
definition. The additional language ensures that the definition
includes other Title I requirements that may be promulgated by the EPA
Administrator in the future.

    We are proposing to approve the Title V program revisions submitted
by VCAPCD because the GHG provisions of the revised rules are
consistent with EPA's approach to Title V in the Tailoring Rule, and
the revision to the definition of ``Federally-Enforceable Requirement''
clarifies the definition and is consistent with EPA's definition of
``applicable requirement'' in 40 CFR 70.2.

C. Public Comment and Proposed Action

    EPA believes the submitted rules fulfill all of the Tailoring
Rule's Title V requirements; therefore we are proposing to approve
these rule changes, adopted in 2010 and 2011, as revisions to the Title
V programs of all five districts. We will accept comments from the
public on this proposal for the next 30 days. Unless we receive
convincing new information during the comment period, we intend to
publish a final approval action.

IV. Statutory and Executive Order Reviews

    Today's proposed action merely proposes to approve State law as
meeting Federal requirements and does not impose additional
requirements beyond those imposed by State law. For that reason, this
proposed action:
     Is not a ``significant regulatory action'' subject to
review by the Office of Management and Budget under Executive Order
12866 (58 FR 51735, October 4, 1993);
     Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described in the Unfunded
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based
on health or safety risks subject to Executive Order 13045 (62 FR
19885, April 23, 1997);
     Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of Section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the Clean Air Act; and
     Does not provide EPA with the discretionary authority to
address disproportionate human health or environmental effects with
practical, appropriate, and legally permissible methods under Executive
Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this proposed action does not have tribal implications
as specified by Executive Order 13175 (65 FR 67249, November 9, 2000),
because the action is not approved to apply in Indian country located
in the State, and EPA notes that it will not impose substantial direct
costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 70

    Environmental protection, Administrative practice and procedure,
Air pollution control, Carbon dioxide, Carbon dioxide equivalents,
Greenhouse gases, Hydrofluorocarbons, Intergovernmental relations,
Methane, Nitrous oxide, Perfluorocarbons, Reporting and recordkeeping
requirements, Sulfur hexafluoride, Incorporation by Reference.

    Authority:  42 U.S.C. 7401 et seq.

    Dated: March 8, 2012.
Jared Blumenfeld,
Regional Administrator, Region IX.
[FR Doc. 2012-6676 Filed 3-20-12; 8:45 am]
BILLING CODE 6560-50-P


## 11.6.2019: Production version of TP-chl model
## 12.17.2019Cleaned and commented
ntumodel <- function(df1, fitout = NULL, runmod = T) {
    source("logtick.exp.R")
    source("binv.R")

    require(rstan)

    nchains <- 6    # select number of chains

    ## omit records that are missing data
    incvec <- ! is.na(df1$ptl.result) & ! is.na(df1$turb.result) &
         ! is.na(df1$chl) & ! is.na(df1$index.site.depth)
    cat("N omitted due to missing records:", sum(!incvec), "\n")
    df1 <- df1[incvec,]

    ## select index sites
    df1 <- subset(df1, sample.type == "MICX")

    ## drop below detection limit turb and tp
    norig <- nrow(df1)
    incvec <- df1$turb.result > 0.01
    df1 <- df1[incvec,]
    incvec <- df1$ptl.result > 1
    df1 <- df1[incvec,]
    incvec <- df1$chl >0
    df1 <- df1[incvec,]
    cat("N dropped for detection limit:", norig - nrow(df1), "\n")

    ## scale chl
    chlmn <- mean(log(df1$chl))
    chlsc <- exp(chlmn)
    df1$chl.sc <- df1$chl/chlsc

    ## define 30 depth classes based on quantiles
    cutp.depth <- quantile(log(df1$index.site.depth), prob = seq(0, 1,length = 31))
    cutm <- 0.5*(cutp.depth[-1] + cutp.depth[-length(cutp.depth)])
    df1$dclass <- cut(log(df1$index.site.depth), cutp.depth, include.lowest = T)
    names(cutm) <- levels(df1$dclass)
    df1$dclassnum <- as.numeric(df1$dclass)

    ##drop HI, only dealing with conterminous US
    incvec <- df1$st.nla2012 == "HI"
    df1 <- df1[!incvec,]

    ## reset factor levels for state
    df1$state <- factor(df1$st.nla2012)
    df1$statenum <- as.numeric(df1$state)

    ## reset L3 ecoregion codes
    df1$us.l3code <- factor(df1$us.l3code)
    df1$econum <- as.numeric(df1$us.l3code)

    ## save data out to disk
    tpchldat <- df1
    save(tpchldat, chlsc, cutp.depth, file = "tpchldat.rda")

    datstan <- list(n = nrow(df1),
                    ndepth = max(df1$dclassnum),depthnum = df1$dclassnum,
                    neco = max(df1$econum), econum = df1$econum,
                    ntu = df1$turb.result,
                    tp = df1$ptl.result,
                    chl = df1$chl.sc)

    print(str(datstan))

    modstan <- '
        data {
            int n;                 // number of samples
            int ndepth;            // number of depth classes
            int depthnum[n];       // depth class assignment
            int neco;              // number of L3 ecoregions
            int econum[n];         // ecoregion assigment
            vector[n] ntu;         // NTU
            vector[n] tp;          // TP
            vector[n] chl;         // Scaled Chl
        }
        parameters {
            real muu_mn;             // grand mean ntu_np
            real<lower= 0> sigu[2];  // standard deviation of ntu_np
            vector[ndepth] eta_u1;
            vector[n] eta_u2;
            real<lower = 0> signtu;  // measurement error of ntu
            real mub;                // mean coef of chl-ntu relationship
            real<lower = 0> sigb;    // standard deviation of b among ecoregions
            vector[neco] etab;
            real<lower = 0> muk[3];  // exponents on chl and u in models
            vector[3] mud;           // mean coef for tp model
            vector<lower = 0>[3] sigd;// SD of ecoregion- or depth-specific coef
            vector[ndepth] etad1;
            vector[neco] etad2;
            vector[neco] etad3;
            real<lower = 0> sigtp;    // measurement error of tp

        }
        transformed parameters {
            vector[ndepth] muu;
            vector[neco] b;
            vector[n] u;
            vector[ndepth] d1;
            vector[neco]  d2;
            vector[neco] d3;

            b = mub + etab*sigb;

            muu = muu_mn + eta_u1*sigu[1];
            u = muu[depthnum] + eta_u2*sigu[2];

            d1 = mud[1] + sigd[1]*etad1;
            d2 = mud[2] + sigd[2]*etad2;
            d3 = mud[3] + sigd[3]*etad3;
        }
        model {
            matrix[n,2] chlk;
            vector[n] uk;

            muu_mn ~ normal(0,3);    // weakly informative priors
            sigu ~ cauchy(0,3);
            eta_u1 ~ normal(0,1);
            eta_u2 ~ normal(0,1);
            signtu ~cauchy(0,3);
            mub ~ normal(0,4);
            sigb ~ cauchy(0,3);
            etab ~ normal(0,1);

            muk ~ normal(1,0.3);    // muk should be somewhere around 1
            mud ~ normal(0,4);
            sigd ~ cauchy(0,3);
            etad1 ~ normal(0,1);
            etad2 ~ normal(0,1);
            etad3 ~ normal(0,1);
            sigtp ~ cauchy(0,3);

           for (i in 1:n) chlk[i,1] = chl[i]^muk[1];
           for (i in 1:n) uk[i] = (u[i] - muu_mn)*muk[2];
           for (i in 1:n) chlk[i,2] = chl[i]^muk[3];

            ntu ~ lognormal(log(exp(b[econum]) .* chlk[,1] + exp(u)), signtu);

            tp ~ lognormal(log(exp(d1[depthnum]) +
                 exp(d2[econum]) .* exp(uk) +
                 exp(d3[econum]) .* chlk[,2]),sigtp);
        }
    '

    if (runmod) {

        rstan_options(auto_write = TRUE)
        options(mc.cores = nchains)
        fit <- stan(model_code = modstan,
                    data = datstan, iter = 900, chains = nchains,
                    warmup = 300, thin = 2)
        return(fit)
    }

    varout <- extract(fitout, pars = c("muk", "mub", "b", "d1", "d2", "d3",
                                  "muu", "muu_mn", "u", "mud"))
    umean <- apply(varout$u, 2, mean)

    # post processing
    grey.t <- adjustcolor("grey39", alpha.f = 0.5)

    muk <- apply(varout$muk, 2, mean)
    mub <- mean(varout$mub)
    mubraw <- mub - muk[1]*log(chlsc)

    # PLOT: relationship between Chl and turbidity
    png(width = 3, height = 2.5, pointsize = 8, units = "in", res = 600,
        file = "chlturb.png")
    par(mar = c(4,4,1,1), mfrow = c(1,1), mgp = c(2.3,1,0))
    plot(log(df1$chl), log(df1$turb.result), axes = F,
         xlab = expression(Chl~italic(a)~(mu*g/L)),
         ylab = "Turbidity (NTU)", pch = 21, col = "grey",
         bg="white")
    logtick.exp(0.001, 10, c(1,2), c(F,F))
    abline(mubraw, muk[1])
    dev.off()

    b <- apply(varout$b, 2, mean)
    braw <- b - muk[1]*log(chlsc)

    d1 <- apply(varout$d1, 2, mean)
    d2 <- apply(varout$d2, 2, mean)
    d3 <- apply(varout$d3, 2, mean)
    muu <- apply(varout$muu, 2,mean)
    muumn <- mean(varout$muu_mn)
    d3raw <- d3 - muk[3]*log(chlsc)
    d2raw <- d2-muk[2]*muumn

    # PLOT: predicted values for Pdiss and muu
    png(width = 6, height = 2.5, pointsize = 8, units = "in", res = 600,
        file = "Pdiss.turb.depth.png")
    par(mar = c(4,4,1,1), mgp = c(2.3, 1, 0), mfrow= c(1,2))
    plot(cutm, exp(muu), xlab = "Depth (m)", axes = F,
         ylab = expression(Turb[np]~(NTU)),
         pch = 21, col = "grey39", bg="white")
    axis(2)
    logtick.exp(0.001, 10, c(1), c(F,F))

    plot(cutm, exp(d1), xlab = "Depth (m)", axes = F,
         ylab = expression(P[diss]~(mu*g/L)),
         pch = 21, col = "grey39", bg="white")
    axis(2)
    logtick.exp(0.001, 10, c(1), c(F,F))
    dev.off()

    # load in ntu_np mean values into main data
    df1$umean <- umean

    # merge ecoregion and depth specific coefficients into main data
    dfd <- data.frame(num = 1:length(d1), d1, muu)
    names(dfd) <- c("dclassnum", "d1", "muu")
    print(nrow(df1))
    df1 <- merge(df1, dfd, by = "dclassnum")
    print(nrow(df1))
    dfd3 <- data.frame(num = 1:length(d3), d3, d3raw, d2, d2raw)
    print(dim(dfd3))
    names(dfd3) <- c("econum", "d3", "d3raw", "d2", "d2raw")
    df1 <- merge(df1, dfd3, by = "econum")

    # save ecoregion coefficients to file for mapping
    dfd3 <- merge(dfd3, unique.data.frame(df1[, c("econum", "us.l3code")]),
                  by = "econum")
    save(dfd3, file= "dfd3.rda")

    # print numerical summaries of parameters
    print("mub")
    print(exp(quantile(varout$mub - varout$muk[,1]*log(chlsc),
                   prob = c(0.05, 0.5, 0.95))))
    print("k distribution")
    print(apply(varout$muk, 2, quantile, prob = c(0.05, 0.5, 0.95)))

    mud <- apply(varout$mud, 2, mean)

    print("mud[2]")
    print(exp(quantile(varout$mud[,2] - varout$muk[,2]*varout$muu_mn,
                       prob = c(0.05, 0.50, 0.95))))
    print("mud[3]")
    print(exp(quantile(varout$mud[,3] - varout$muk[,3]*log(chlsc),
                       prob = c(0.05, 0.5, 0.95))))

    # compute mean predicted TP
    df1$predout <- exp(df1$d1) + exp(df1$d2)*exp(df1$umean - muumn)^muk[2] +
        exp(df1$d3)*df1$chl.sc^muk[3]

    png(width = 4, height = 4, pointsize = 10, units = "in", res = 600,
        file = "pred.v.obs.all.png")
    par(mar = c(4,4,1,1), mgp = c(2.3,1,0), bty = "l")
    plot(log(df1$predout), log(df1$ptl.result), xlab = "Predicted TP",
         ylab = "Observed TP",  pch = 21, col = "grey39",
         bg = "white", axes = F)
    logtick.exp(0.001, 10, c(1,2), c(F,F))
    abline(0,1)
    dev.off()

    rmsfnc <- function(x,y) {
        return(sqrt(sum((x-y)^2)/length(x)))
    }
    print("Whole data RMS:")
    print(rmsfnc(log(df1$predout), log(df1$ptl.result)))

    # PLOT: NTU_np vs TP, Chl vs TP
    png(width = 6, height = 2.5, pointsize = 8, units = "in", res = 600,
        file = "tpchl.png")

    par(mar = c(4,4,1,1), mfrow = c(1,2), mgp = c(2.3,1,0))
    plot(df1$umean, log(df1$ptl.result), xlab = expression(Turb[np]~(NTU)),
         ylab = expression(TP~(mu*g/L)), pch = 21, col = "grey",
         bg="white", axes = F)
    logtick.exp(0.000001, 10, c(1,2), c(F,F))
    x <- seq(min(df1$umean), max(df1$umean), length = 40)
    predout <- matrix(NA, ncol = 3, nrow = length(x))
    for (i in 1:length(x)) {
        y <- varout$mud[,2] + varout$muk[,2]*x[i] - varout$muu_mn*varout$muk[,2]
        predout[i,] <- quantile(y, prob = c(0.05, 0.5, 0.95))
    }
    polygon(c(x, rev(x)), c(predout[,1], rev(predout[,3])),
            col = grey.t, border = NA)
    lines(x, predout[,2])

    plot(log(df1$chl), log(df1$ptl.result),
         xlab = expression(Chl~italic(a)~(mu*g/L)),
         ylab = expression(TP~(mu*g/L)), pch= 21, col = "grey",
         bg = "white", axes = F)
    logtick.exp(0.001, 10, c(1,2), c(F,F))
    x <- seq(min(log(df1$chl)), max(log(df1$chl)), length = 40)
    predout <- matrix(NA, ncol = 3, nrow = length(x))
    for (i in 1:length(x)) {
        y <- varout$mud[,3] - varout$muk[,3]*log(chlsc) +
            varout$muk[,3]*x[i]
        predout[i,] <- quantile(y, prob = c(0.05, 0.5, 0.95))
    }
    polygon(c(x, rev(x)), c(predout[,1], rev(predout[,3])),
            col = grey.t, border = NA)
    lines(x, predout[,2])

    dev.off()

}

## runmod variable set to T to run simulation and set to F to
##  run post processing.
fitout <- ntumodel(dat.merge.all, runmod = T)
## post processing
ntumodel(dat.merge.all, fitout, runmod = F)


[Federal Register Volume 76, Number 45 (Tuesday, March 8, 2011)]
[Notices]
[Pages 12719-12720]
[FR Doc No: 2011-5210]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

[Project No. 176-018]

City of Escondido, California, and Vista Irrigation District;
Notice of Application Accepted for Filing, Ready for Environmental
Analysis, and Soliciting Comments, Motions To Intervene, Protests,
Recommendations, and Terms and Conditions

    Take notice that the following hydroelectric application has been
filed with the Commission and is available for public inspection:
    a. Application Type: Conduit Exemption.
    b. Project No: 176-018.
    c. Date Filed: December 3, 2010.
    d. Applicant: City of Escondido, California, (Escondido) and Vista
Irrigation District (Vista).
    e. Name of Project: Bear Valley Powerhouse Project.
    f. Location: On the San Luis Rey River in San Diego County, near
Escondido, California. The project occupies 290 acres of Federal lands
under the jurisdiction of the U.S. Forest Service and the U.S. Bureau
of Land Management. The project also occupies approximately 0.25 acre
of Indian reservation lands owned by the La Jolla, San Pasqual, and
Rincon Indian Tribes.
    g. Filed Pursuant to: Federal Power Act 16 U.S.C. 791a-825r).
    h. Applicant Contact: Donald R. Lincoln, Special Counsel for the
City of Escondido, Endeman, Lincoln, Turek & Heater, LLP, 600 ``B''
Street, Suite 2400, San Diego, CA 92101-4582,<PHONE_NUMBER>; and Don
A. Smith, Director of Water Resources, Vista Irrigation District, 1391
Engineer Street, Vista, CA 92081,<PHONE_NUMBER>.
    i. FERC Contact: Carolyn Templeton,<PHONE_NUMBER>, or
<EMAIL_ADDRESS>    j. This application has been accepted for filing and is now ready
for environmental analysis.
    k. Deadline for filing comments, motions to intervene, protests,
recommendations, and terms and conditions: 60 days from the issuance
date of this notice; reply comments are due 105 days from the issuance
date of this notice.
    All documents may be filed electronically via the Internet. See 18
CFR 385.2001(a)(1)(iii) and the instructions on the Commission's Web
site http://www.ferc.gov/docs-filing/efiling.asp. Commenters can submit
brief comments up to 6,000 characters, without prior registration,
using the eComment system at http://www.ferc.gov/docs-filing/ecomment.asp. You must include your name and contact information at the
end of your comments. For assistance, please contact FERC Online
Support at<EMAIL_ADDRESS>or toll free at 1-866-208-3676,
or for TTY,<PHONE_NUMBER>. Although the Commission strongly encourages
electronic filing, documents may also be paper-filed. To paper-file,
mail an original and seven copies to: Kimberly D. Bose, Secretary,
Federal Energy Regulatory Commission, 888 First Street, NE.,
Washington, DC 20426. Please include the project number (P-176-018) on
any documents filed.
    The Commission's Rules of Practice require all intervenors filing
documents with the Commission to serve a copy of that document on each
person on the official service list for the project. Further, if an
intervenor files comments or documents with the Commission relating to
the merits of an issue that may affect the responsibilities of a
particular resource agency, they must

also serve a copy of the document on that resource agency.
    l. Description of Project: Escondido and Vista are the joint
current owners and operators of the currently licensed Escondido
Hydroelectric Project facilities and hold the current Commission
license for the Escondido Hydroelectric Project. The primary purpose of
the project has historically been for water delivery for consumptive
purposes, including agricultural and municipal-industrial uses.
    The most upstream component of the Escondido Hydroelectric Project
is the Escondido canal diversion dam, a concrete structure located on
the San Luis Rey River within the La Jolla Indian Reservation
approximately 10 miles downstream from Lake Henshaw. The dam diverts
San Luis Rey River water into the 13.6-mile-long Escondido canal that
extends from a diversion dam to Lake Wohlford. The canal traverses the
La Jolla, Rincon, and San Pasqual Indian reservations, as well as other
Federal and private lands. Historically, the canal has delivered 10 to
15 percent of the waters diverted into the Escondido canal to the
Rincon Indian Reservation. Lake Wohlford stores the water obtained from
the San Luis Rey River and Escondido Creek watersheds, which is then
used consumptively by Escondido and Vista. Water is delivered from Lake
Wohlford through a 4,022-foot-long penstock through the Bear Valley
powerhouse or bypasses the powerhouse. The powerhouse location takes
advantage of the 495 feet of elevation drop from Lake Wohlford to the
water delivery point. From the Bear Valley powerhouse, water is
delivered via underground conduits to Escondido's water treatment
plant. From the treatment plant, water is distributed for consumptive
uses on a prorated basis into the distribution systems of both
Escondido and Vista.
    The hydroelectric generation component of the water conveyance
system consists of the existing Bear Valley powerhouse, which has a
nameplate generation capacity of 1.5 megawatt. The powerhouse consists
of two 1,010-horsepower impulse turbines and two 750 kilowatt (kW)
generators which operate at a gross head of 495 feet. Two 16-inch
submerged sleeve valves allow for water delivery from the Project when
it is necessary to bypass the turbines due to maintenance or other
operational constraints. The average annual production was 4,903,000
kilowatt-hours (kWh) per year for fiscal year 1987 through 2006. The
capacity and energy is sold to San Diego Gas & Electric Company (at
avoided cost rates).
    In a concurrent filing, the applicants have filed an application
for surrender of the remaining facilities of the Escondido
Hydroelectric Project.
    m. A copy of the application is available for review at the
Commission in the Public Reference Room or may be viewed on the
Commission's Web site at http://www.ferc.gov using the ``eLibrary''
link. Enter the docket number excluding the last three digits in the
docket number field to access the document. For assistance, contact
FERC Online Support. A copy is also available for inspection and
reproduction at the address in item (h) above.
    You may also register online at http://www.ferc.gov/docs-filing/esubscription.asp to be notified via e-mail of new filings and
issuances related to this or other pending projects. For assistance,
contact FERC Online Support.
    p. Protests or Motions to Intervene--Anyone may submit a protest or
a motion to intervene in accordance with the requirements of Rules of
Practice and Procedure, 18 CFR 385.210, 385.211, and 385.214. In
determining the appropriate action to take, the Commission will
consider all protests filed, but only those who file a motion to
intervene in accordance with the Commission's Rules may become a party
to the proceeding. Any protests or motions to intervene must be
received on or before the specified deadline date for the particular
application.
    q. All filings must (1) bear in all capital letters the title
``PROTEST,'' ``MOTION TO INTERVENE,'' ``COMMENTS,'' ``REPLY COMMENTS,''
    ``RECOMMENDATIONS,'' or ``TERMS AND CONDITIONS;'' (2) set forth in
the heading the name of the applicant and the project number of the
application to which the filing responds; (3) furnish the name,
address, and telephone number of the person protesting or intervening;
and (4) otherwise comply with the requirements of 18 CFR 385.2001
through 385.2005. All comments, recommendations, or terms and
conditions must set forth their evidentiary basis and otherwise comply
with the requirements of 18 CFR 4.34(b). Agencies may obtain copies of
the application directly from the applicant. Any of these documents
must be filed by providing the original and eight copies to: The
Secretary, Federal Energy Regulatory Commission, 888 First Street, NE.,
Washington, DC 20426. An additional copy must be sent to Director,
Division of Hydropower Administration and Compliance, Office of Energy
Projects, Federal Energy Regulatory Commission, at the above address. A
copy of any protest or motion to intervene must be served upon each
representative of the applicant specified in the particular
application. A copy of all other filings in reference to this
application must be accompanied by proof of service on all persons
listed in the service list prepared by the Commission in this
proceeding, in accordance with 18 CFR 4.34(b) and 385.2010.
    r. With this notice, we are initiating consultation with the
California State Historic Preservation Officer, as required by section
106 of the National Historic Preservation Act, and the regulations of
the Advisory Council on Historic Preservation, 36 CFR 800.4.

    Dated: March 1, 2011.
Kimberly D. Bose,
Secretary.
[FR Doc. 2011-5210 Filed 3-7-11; 8:45 am]
BILLING CODE 6717-01-P


Significant New Alternatives Policy Program

Refrigeration and Air Conditioning Sector

Risk Screen on Substitutes for CFC-12 in Household Refrigerators and
Household Freezers.

Substitute: Isobutane

This risk screen contains no Clean Air Act (CAA) Confidential Business
Information (CBI) and, therefore, may be disclosed to the public.

1. 	INTRODUCTION

Ozone-depleting substances (ODS) are being phased out of production in
response to a series of diplomatic and legislative efforts that have
taken place over the past decade, including the Montreal Protocol and
the Clean Air Act Amendments of 1990 (CAAA).  The U.S. Environmental
Protection Agency (EPA), as authorized by Section 612 of the CAAA, is
developing a program to evaluate the human health and environmental
risks posed by alternatives to ODS.  The main purpose of EPA's program,
called the Significant New Alternatives Policy (SNAP) Program, is to
identify acceptable and unacceptable substitutes for ODS in specific end
uses.

EPA’s decision on the acceptability of a substitute is based largely
on the findings of a screening assessment of potential human health and
environmental risks posed by the substitute in specific applications.
EPA has already screened a large number of substitutes in many end uses
within all of the major ODS-using sectors, including refrigeration and
air conditioning, solvent cleaning, foam blowing, aerosols, fire
suppression, adhesives, coatings and inks, and sterilization. The
results of these risk screens are presented in a series of Background
Documents that are available in EPA's docket.

The purpose of this report is to supplement EPA’s Background Document
on the refrigeration and air conditioning sector (EPA 1994) (hereinafter
referred to as the Background Document) by adding to the list of
potential substitutes for specific end-uses of CFC-12 in this sector.
Proposed end-use applications considered in this analysis include new
replacements for household refrigerators and household freezers.  The
specific proposed CFC-12 substitute examined in this report is isobutane
(R600a).   Table 1 presents the composition of the substitute, including
the maximum estimated concentrations of impurities which may be present
in the substitute.

Table   SEQ Table \* ARABIC  1 . Composition of the Substitute.

Component	Concentration

(Weight Percent)

Substitute

Isobutane	(99.5%

Potential Impurities (maximum concentration)

Propane and N-butane	0.5%

1,3-Butadiene	0.0005%

N-Hexane	0.005%

Benzene	0.0001%

Table 1. Composition of the Substitute (continued)

Component	Concentration

(Weight Percent)

Sulfur	0.0001%

Liquid phase water	0.0005%

Air	0.05% (V/V)

The potential risks associated with use of substitutes in residential
refrigeration have been examined at length in the Background Document.
The reader is referred to this reference for a detailed discussion of
the methodologies used to conduct this risk screen.  Presently, EPA’s
SNAP Program has not approved any hydrocarbon blends as a substitute for
CFC-12 in residential appliance end uses, such as those intended for
this substitute (i.e., household refrigerators and household freezers).
Of particular concern are the flammability risks associated with
hydrocarbon blends during manufacturing, use, servicing, and disposal of
household appliances.  Occupational exposure modeling was performed to
ensure that use of the proposed substitute in the application listed
above did not pose unacceptable risk to workers.  Consumer exposure
modeling was performed to examine potential catastrophic releases of the
substitute.  Lastly, general population exposure modeling was performed
to ensure that the proposed substitute would not pose unacceptable risk
to the population at large.

Section 2 of this report summarizes the results of the risk screen for
the proposed substitute.  The remainder of the report is organized into
the following sections:

Section 3: Atmospheric Assessment

Section 4: Flammability Assessment

Section 5: Asphyxiation Assessment

Section 6: Toxicity Assessment

Section 7: Volatile Organic Compound Assessment

Section 8: References

2.	 SUMMARY OF RESULTS

Isobutane is recommended for SNAP approval for household refrigerators
and freezers.  EPA's risk screen indicates that the use of the proposed
substitute and its constituents will be less harmful to the atmosphere
than the continued use of CFC-12.   No significant toxicity risks to
workers, consumers, or the general population are expected according to
occupational and consumer exposure modeling.  Flammability models
indicate that risks of explosions are not a concern for consumers,
provided the refrigerant is not used in small, poorly ventilated spaces
(see Section 4).  Caution must be used in manufacturing facilities and
by refrigeration technicians to minimize explosion risk, while in the
presence of large quantities of the substitute.  This includes
installation of proper safety equipment during manufacturing,
transportation, and storage and providing proper training and
certification to technicians.  EPA recommends that American Society of
Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standards
15 and 34 be followed.

3. 	ATMOSPHERIC MODELING

This section presents an assessment of the potential risks to
atmospheric integrity posed by the use of isobutane in the residential
refrigeration sector.  The ODP, GWP, and atmospheric lifetime (ALT) of
the proposed substitute are presented in Table 2.

The environmental impacts resulting from use of isobutane are generally
in the range of those predicted for other substitutes examined in the
Background Document.  The substitute is substantially less harmful to
the ozone layer, has less climate impact, and a shorter atmospheric
lifetime compared to CFC-12.

Table   SEQ Table \* ARABIC  2 .  Atmospheric Impacts of Isobutane
Compared to CFC-12.

Refrigerant	Ozone Depleting Potential (ODP)	Global Warming Potential
(GWP)	Atmospheric Lifetime years (ALT)

Isobutane	0a	8a	<1b

CFC-12	1c	8,100d	100c

a Isobutane SNAP Submission (GE 2008).

b Atmospheric lifetime (ALT) not provided in SNAP submission.   Calm and
Hourahan (2007) indicate the ALT is 0.019 years, or about one week.

c Available at: http://www.epa.gov/ozone/ods.html.

d IPCC, Second Assessment Report (1996).

4.	       FLAMMABILITY ANALYSIS

Due to its flammable nature, isobutane could pose a significant safety
concern for workers and consumers if it is not handled carefully.  In
the presence of an ignition source (e.g., static electricity, a spark
resulting from a closing door, or a cigarette), an explosion or a fire
could occur when the concentration of isobutane exceeds its lower
flammability limit (LFL) of 18,000 ppm.  Therefore, it is important to
ensure that the levels of isobutane do not exceed 18,000 ppm.  In
production facilities or other facilities where large quantities of the
refrigerant will be stored, proper safety precautions should be in place
to minimize the risk of explosion.  White goods installed with isobutane
should be clearly labeled as containing a flammable refrigerant charge
and designed to prevent catastrophic leaks.  Furthermore, only
refrigerant technicians certified to work with flammable refrigerants
should handle these units during manufacturing, installation, servicing,
transportation and disposal.

To determine whether flammability would be a concern for consumers, a
reasonable worst-case scenario analysis was performed to model
catastrophic release of the refrigerant.  The analysis models the
release of charge from a refrigerator into a kitchen.  The kitchen
volume is assumed to be 18 m3 (635 ft3) or approximately 2.7 x 2.7 m
(8.9 x 8.9 ft) for a square room with 2.4 m (8 ft) ceilings (EPA 1994).
In the analysis, the maximum permissible leak per the standard UL 250
Supplement SA (50 g) is assumed to be emitted within one minute and the
kitchen is assumed to have an air flow rate of 2.5 air exchanges per
hour.  Given these conservative assumptions, the assumed reasonable
“worst-case” scenario is highly unlikely.

Horizontal stratification is also assumed since isobutane is denser than
air and will settle in higher concentrations closer to the ground.  In
order to simulate the horizontal concentration gradient that will occur
because of the weight differential between the refrigerant and air, it
is assumed that 95 percent of the leaked refrigerant mixes evenly into
the bottom 0.4 meter of the room, and the rest of the refrigerant mixes
evenly in the remaining volume (Kataoka 1999).

Under catastrophic release scenarios, the maximum instantaneous
concentration of isobutane in the lower stratum of the room would be
approximately 37 percent of its LFL for the average room size assumed,
as shown in Table 3.   The maximum instantaneous concentration is lower
in the upper stratum of the room, as only five percent of the leaked
refrigerant is present in this stratum, and this stratum has a greater
volume than the lower stratum.  For flammability to be of concern under
the conservative (protective) assumptions described above, the volume of
the kitchen would have to be about 7 m3 (247 ft3).  Assuming a square
room with a ceiling height of 2.4 m (8.0 ft), this equates to a 1.7 x
1.7 m (5.6	 x 5.6 ft) kitchen.   Very limited data are available
regarding the distribution of kitchen volumes in the United States.
However, an analysis by Murray (1997) which aggregated data from over 60
different projects reported the minimum kitchen volume encountered as 31
m3.  Further, only one percent of houses sampled had a kitchen smaller
than 53 m3.

To avoid the risk of fire and explosion, it is recommended that the
refrigerators not be installed in small, poorly ventilated spaces such
as very small ‘galley’ kitchens or storage closets (especially as
other equipment or appliances in the space would reduce the effective
volume of the room).  However, based on the available data regarding
kitchen volumes, it is not likely that a kitchen would exist which would
be small enough for flammability to be a concern, even under a
reasonable worst-case scenario.  For full-sized kitchens the risk of
explosion is minimal.  The installation of leak prevention devices would
further protect against the very limited risk of explosion.  For
example, in commercial refrigeration end-uses, refrigerant leak
prevention systems can be used to capture leaked refrigerant in a
receiving tank during over pressure events, rather than venting the
refrigerant to the atmosphere.  Additionally, in motor vehicle
air-conditioning, an outflow prevention device can be used to prevent
leakage events when the heat exchanger of a unit is damaged.    ICF
recommends that similar safety devices (designed for residential
refrigerators and freezers) be installed in units containing isobutane
to prevent refrigerant leaks and thereby further reduce the risk of
explosion.

Table   SEQ Table \* ARABIC  3 .  Flammability Assessment

Room Type/Appliance Type	Reasonable Worst-Case Scenario	Flammability
Threshold Scenario

	Room Size (m3)	Maximum Instantaneous Concentration

(ppm) a,b	Room Size (m3)	Maximum Instantaneous Concentration

(ppm) a,b

Kitchen/Refrigerator	18 (635 ft3)	6,647	7 (247 ft3)	17,006

a Lower Flammability Limit of isobutane is equal to 18,000 ppm.

b Values provided in these columns refer to the concentration in the
lower stratum of the room.

Catastrophic releases of large quantities of refrigerant during
servicing and manufacturing, especially in areas where large amounts of
refrigerant are stored, could cause an explosion.  For this reason, it
is important that only properly trained and certified refrigerant
technicians handle isobutane.  The submitter has provided information
regarding their training program for service technicians.  The program
includes detailed information regarding proper recovery of the
refrigerant prior to service as well as information on servicing the
refrigerator and charging the system with isobutane (GE SNAP Submission
2008).   This training should be provided for all technicians who will
be servicing refrigerators using isobutane.    As a further precaution,
isobutane storage and transport equipment should be installed with
safety devices that minimize the likelihood of catastrophic releases.
For example, NFPA 58 Liquefied Petroleum Gas Code (NFPA 2008) requires
the use of overfill protection devices (OPD) on cylinders to minimize
the likelihood of leaks.  The NPFA 58 Code also contains storage and
transportation requirements/guidelines.  Similar equipment safety and
procedural requirements should be implemented for this substitute.

It is important that the strictest standards be followed during
manufacturing.  It is recommended that refrigerants be properly stored
and caution used within manufacturing facilities to minimize explosion
risk and that workers adhere to the requirements set by OSHA under 29
CFR 1910.  OSHA requirements include proper ventilation and storage
practices within manufacturing facilities to prevent fire and explosion.
 Proper ventilation should be maintained at all times during the
manufacture of equipment containing isobutane through adherence to good
manufacturing practices. If refrigerant levels in the air surrounding
the equipment rise above one-fourth of the lower flammability limit, the
space should be evacuated and re-entry should only occur after the space
has been properly ventilated.  Ventilation is also of the utmost
importance to mitigate the risk of fire or explosion when servicing
equipment using isobutane.  During servicing operations, technicians
should ensure that proper ventilation is in place through the use of
fans (or other mechanical ventilation devices) and portable refrigerant
detectors should be used to alert technicians to the presence of
flammable gases in the area.

5.                ASPHYXIATION

The risk of asphyxiation for a reasonable “worst-case” scenario was
investigated for isobutane.  This analysis does not consider conditions
that are likely to occur that would reduce the levels to which
individuals would be exposed, such as open doors or windows, fans
operating, conditioned airflow (either heated or cooled), or even
seepage between the door and door frame.

The maximum leak of isobutane necessary to reduce the oxygen levels to
12 percent in air, in a kitchen of volume 18 m3 (635 ft3) (EPA 1994),
was calculated, assuming horizontal stratification of the refrigerant
and the air.  Horizontal stratification is assumed since isobutane is
denser than air and will settle in higher concentrations closer to the
ground.  Assuming that nitrogen and oxygen retain the same relative
volumes in the rooms with the balance composed entirely of isobutane,
and that the pressure of the room does not increase significantly with
the addition of the refrigerant, a leak of approximately 625 g would be
necessary to reach 12 percent oxygen in the lower stratum.  This amount
is more than twelve times the maximum permissible leak for a single
isobutane refrigerator or freezer (50 g).  The size of a leak needed to
reach the same effect in the upper strata would be even greater because
of the stratum’s larger volume.  For asphyxiation to be of concern
with the maximum permissible leak, under the conservative (protective)
assumptions described above, the volume of the kitchen would have to be
about 1.5 m3 (53 ft3).  Assuming a square room with a ceiling height of
2.4 m (8.0 ft), this equates to a 0.8 x 0.8 m (2.6 x 2.6 ft) kitchen.

The results of the asphyxiation assessment are summarized in Table 4
below.  It is recommended that isobutane refrigerators not be installed
in small, poorly ventilated spaces, such as very small ‘galley’
kitchens, to avoid the risk of asphyxiation.  However, based on the
available data regarding kitchen volumes (see Section 4), it is not
likely that a kitchen would exist which would be small enough for
asphyxiation to be a concern, even under a reasonable worst-case
scenario.  Therefore, EPA does not believe that the use of isobutane in
this end-use poses a significant risk of asphyxiation or impaired
coordination to consumers.

Table   SEQ Table \* ARABIC  4 .  Asphyxiation Assessment

Room Type/Appliance Type	Maximum Permissible Leak from Appliance (g) a
Reasonable Worst-Case Scenario	Asphyxiation Threshold Scenario

Room Size (m3)	Leak Size Causing Impairment (g)b	Room Size (m3)	Leak
Size Causing Impairment (g)b

Kitchen/Refrigerator	50	18 (635 ft3)	625	1.5 (53 ft3)	50

a Fifty grams is the maximum permissible refrigerant leak per the
standard UL 250 Supplement SA.

b Values provided in these columns refer to the leak size required to
cause impairment in the lower stratum of the room.

6. 		TOXICITY REFERENCE VALUES FOR SUBSTITUTES

To assess potential health risks from exposure to this substitute in the
residential refrigeration sector, EPA identified the relevant toxicity
threshold values for comparison to modeled exposure concentrations for
different scenarios.  For the occupational exposure analysis, potential
risks from chronic and acute worker exposure were evaluated by comparing
exposure concentrations to available occupational exposure limits.
Occupational exposure limits are typically established for either an
eight-hour or ten-hour time period for long-term exposure, such as the
Workplace Guidance Levels (WGLs), or for a 10 to 30-minute period for
short-term exposure, such as the Emergency Guidance Levels (EGLs), as
shown in Table 5.  Because they are designed to assess risks from acute
exposure, emergency guidance levels are used to assess risks from
short-term consumer exposures.  Reference concentrations (RfCs) are used
to assess risks to the general population from exposure to ambient air
releases and to assess potential risks associated with chronic consumer
exposures.  A list of the relevant toxicity limits is shown in Table 5.
Table 6 provides definitions of the acronyms used in Table 5.  EPA’s
approach for identifying or developing these values is discussed in
Chapter 3 of the Background Document.

Table   SEQ Table \* ARABIC  5 .  Toxicity Levels of Isobutane and
Potential Impurities

	Long-term Exposure

ppm	Short-term Exposure

ppm	Reference Concentration (RfC)

mg/m3

Substitute

Isobutane	800 a (NIOSH REL)	18000 b (NOAEL)	0.95 c

Potential Impurities

Propane	1000 d

(OSHA PEL/NIOSH REL)	2100 d (IDLH)	0.9 c

n-Butane	800 e (NIOSH REL)	NA	0.95 c

1,3-Butadiene	1 f (OSHA PEL)	5 f (OSHA PEL - STEL)

670 g (10 minute interim AEGL-1)	2 x 10-3 h

N-Hexane	50 I (NIOSH REL)	1100 i (IDLH)	0.7 j

Benzene	0.1 k (NIOSH REL)	1 k (NIOSH STEL)

500 k (IDLH)	3 x 10 -2 l

Sulfur	NA	NA	NA

NA  = Not Available

a http://www.cdc.gov/niosh/npg/npgd0350.html

b OSHA (2004) notes the following regarding isobutane: “OSHA does not
have a PEL for isobutane, which is affirmed as "generally recognized as
safe" as a direct human food ingredient (21 CFR 184.1165). No toxic
effects reported below 18,000 ppm.”

c SNAP Refrigerant Background Document (EPA 1994).

d http://www.cdc.gov/Niosh/npg/npgd0524.html

e http://www.cdc.gov/niosh/npg/npgd0068.html

f http://www.cdc.gov/niosh/npg/npgd0067.html

g http://www.epa.gov/opptintr/aegl/pubs/rest148.htm

h http://www.epa.gov/ncea/iris/subst/0139.htm#refinhal

i http://www.cdc.gov/niosh/npg/npgd0322.html

j http://www.epa.gov/ncea/iris/subst/0486.htm#refinhal

k http://www.cdc.gov/niosh/npg/npgd0049.html

l http://www.epa.gov/iris/subst/0276.htm#refinhal

Table   SEQ Table \* ARABIC  6 .  Explanation of Toxicity-Related
Acronymsa

Organization 	Definition

OSHA	Occupational Safety and Health Administration

NIOSH	National Institute for Occupational Safety and Health

Exposure Limit	Definition	Explanation

AEGL-1	Acute Exposure Guideline Level	The AEGL-1 “is the airborne
concentration… above which it is predicted that the general
population, including susceptible individuals, could experience notable
discomfort, irritation, or certain asymptomatic nonsensory effects.
However, the effects are not disabling and are transient and reversible
upon cessation of exposure” (EPA 2008a).

IDLH	Immediately Dangerous to Life and Health	If exposed to this
concentration, room occupants are expected to be able to escape the room
within 30 minutes without experiencing escape-impairing or irreversible
health effects.

NOAEL	No Observed Adverse Effect Limit	“The highest exposure level at
which there are no biologically significant increases in the frequency
or severity of adverse effect between the exposed population and its
appropriate control; some effects may be produced at this level, but
they are not considered adverse or precursors of adverse effects.”b

PEL	Permissible Exposure Limit

	This is an 8-hour time-weighted average exposure limit set by OSHA.

PEL - STEL	Permissible Exposure Limit - Short-term exposure limit.	This
is a 15-minute time-weighted average exposure limit set by OSHA.

REL	Recommended Exposure Limit	This is a 10-hour time-weighted average
exposure limit set by NIOSH.

RfC	Reference Concentration	A concentration “designed to protect the
general population against adverse systemic (i.e., noncancer)
effects.”

aAll information in this table taken from EPA (1994), except where noted
otherwise.

b From   HYPERLINK "http://www.epa.gov/riskassessment/glossary.htm#n"
http://www.epa.gov/riskassessment/glossary.htm#n

6.1  	OCCUPATIONAL EXPOSURE

Occupational exposure modeling was performed for the proposed substitute
to ensure that use of the substitute does not pose an unacceptable risk
to workers.  The methodology used for this screening assessment is based
on the one used in the occupational exposure and hazard analysis
described in Chapter 5 of the Background Document. A box-model approach
was used to evaluate potential worker exposure to alternative
refrigerants.   This approach has been widely used for many years to
estimate probable exposures of workers to hazardous airborne materials,
and has been described in detail by the National Institute for
Occupational Safety and Health (NIOSH).  This model takes into
consideration the duration and magnitude of the resulting exposure which
is influenced by 1) duration and intensity of the release, 2) rate at
which contaminated air is diluted with uncontaminated air, 3) proximity
of the worker to the source of the release, and 4) the length of time
the worker remains in the affected space.

Estimates of refrigerant release per event for various release scenarios
and data on number of events were obtained from the Vintaging Model.
The release per event was conservatively assumed to be 1 percent of the
equipment charge during manufacturing and 3 percent of the equipment
charge during disposal.  The release rate per event was multiplied by
the number of events estimated to occur over a workday.  For equipment
manufacturing, the number of events per workday was assumed to equal the
number of units containing the substitute produced per plant per year
divided by 365 workdays per year.  For the purposes of this model, the
isobutane market penetration rate was estimated using data from the SNAP
submission and the Vintaging Model (version 4.3_2.16.09) and one
production facility was assumed to be in operation.  These assumptions
result in approximately 44 events/manufacturing facility/day.  For
disposal, it was conservatively assumed that 100 units are disposed
during an 8-hour work day.

The maximum time weighted average (TWA) exposure was estimated for each
exposure scenario, and this value compared to the Workplace Guidance
Levels (WGLs) for isobutane and the potential impurities in the
substitute.  The modeling results indicate that both the short-term
(15-minute and 30-minute) and long-term (8-hour) worker exposure
concentrations at no point exceed 2 percent of the WGLs.  Table 7
displays the maximum estimated 15-minute TWA occupational exposure
levels of isobutane and the potential impurities in the substitute.
Even these maximum estimated short-term occupational levels are
significantly lower than the 8-hour or 10-hour long-term WGLs, and
therefore occupational exposure to isobutane and the potential
impurities is not considered a toxicity threat.

Table   SEQ Table \* ARABIC  7 .  Occupational Risk Assessment

	Maximum 15-minute TWA Occupational Exposure Levels (ppm)	Workplace
Guidance Levels

(ppm) a	Workplace Guidance Levels Time Period

Substitute

Isobutane	10.16	800	10-hour TWA

Potential Impurities

Propane and Butane b	5.8 x 10-2	1000 (propane)

800 (butane) 	10-hour TWAc

1,3-butadiene	5.5 x 10-5	1	8-hour TWA

n-Hexane	3.4 x 10-4	50	10-hour TWA

Benzene	7.6 x 10-6	0.1	10-hour TWA

Sulfur	1.9 x 10-5	NA	NA

NA = Not Available

a. See Table 5 for more information.

b. Propane and Butane weight percentage in substitute presented as one
single value in submission.  Exposure level is well below the WGL for
either constituent.

c. The WGL for Propane is set as a 1000 ppm 8-hr TWA by OSHA and a 10-hr
TWA by NIOSH.  The Butane value is a 10-hr TWA.

6.2	CONSUMER EXPOSURE

This section presents estimates of potential consumer exposures to
isobutane in home appliances.  A consumer exposure analysis was
performed to examine potential catastrophic release of the substitute
under a reasonable “worst-case” scenario.  Estimates for
acute/short-term consumer exposures resulting from catastrophic leakage
of refrigerant from residential refrigerators were examined.  The
analysis was undertaken to determine the 15- and 30-minute TWA for the
substitute, which were then compared to the standard toxicity limits
presented in Table 5 to assess the risk to consumers.  However, the TWA
values are fairly conservative as the analysis does not consider opened
windows, fans operating, conditioned airflow (either heated or cooled)
and other variables that would reduce the levels to which individuals
would be exposed.

The model involves a refrigerant leak from a refrigerator into an
enclosed kitchen of volume 18 m3 (635 ft3). The model assumes that the
individual is present at the start of the leak and the individual
remains in the room while the refrigerant is released. It is also
assumed that horizontal stratification causes most of the refrigerant to
settle in higher concentrations closer to the ground.  Considering the
horizontal stratification is important because children, a particularly
vulnerable segment of the population, breathe air that is closer to the
ground.  In order to simulate the horizontal concentration gradient that
will occur because of the weight differential between the refrigerant
and air, it is assumed that 95 percent of the leaked refrigerant mixes
evenly into the bottom 0.4 meter of the room, and the rest of the
refrigerant mixes evenly in the remaining volume (Kataoka 1999).
Exposure concentrations were calculated using the box model described in
the Background Document, which was adapted to estimate concentrations on
a minute-by-minute basis.  It was assumed that the maximum permissible
leak per the standard UL 250 Supplement SA (50 g) would be released
during a time span of 1 minute, at which time the concentration of
isobutane will peak, and then steadily decline onwards.  Refrigerant
concentrations were modeled under two air change scenarios believed to
represent the range of potential flow rates for a home, assuming flow
rates of 2.5 and 4.5 air changes per hour (ACH) (Sheldon 1989).

The highest concentrations of the refrigerant occur in the lower stratum
of the room and when assuming 2.5 ACH.  The highest expected levels of
consumer exposure based on this analysis are presented in Table 8 below.

Table   SEQ Table \* ARABIC  8 .  Consumer Exposure Assessment

	15-minute TWA Consumer Exposure (ppm)	30-minute TWA Consumer Exposure
(ppm)

Substitute

Isobutane	5,025	3,844

Potential Impurities

Propane and Butane a	29	22

1,3-butadiene	0.03	0.02

n-Hexane	0.17	0.13

Benzene	0.004	0.003

Sulfur	0.009	0.007

TWA = Time Weighted Average

a. Propane and Butane weight percentage in substitute presented as one
single value in submission.  Exposure level is well below the exposure
limits for either constituent.

OSHA (2004) states no toxic effects are reported with exposures to
isobutane below 18,000 ppm.  Even under the very conservative
assumptions used in the consumer exposure modeling, both the estimated
15-minute and 30-minute consumer exposures to isobutane are lower than
this level and thus should not pose a toxicity threat.   The exposure
levels of the impurities are also lower than their respective short-term
toxicity levels (see Table 5) and thus should not pose a toxicity
threat.

6.3  	GENERAL POPULATION EXPOSURE

In the SNAP Background document for refrigerants (EPA 1994), the RfC
value for isobutane is 0.95 m/m3.  We compared this RfC to estimated
factory releases and on-site releases.  This gives a ratio of exposure
concentration to RfC that varies between 1.3 x 10-5 to 1.7 x 10-1,
depending on the type of release scenario.  Ratios of exposure
concentration to RfC for the substitute’s impurities were even lower.
Since the exposure concentrations for the substances are lower than the
RfC values, the substitute is not expected to pose a toxicity threat to
the general population.

7. 	VOLATILE ORGANIC COMPOUND (VOC) ANALYSIS

Isobutane has not been exempted as a VOC under the CAA (40 CFR 51.000).
However, through regulations and standard industry practices, VOC
emissions should be controlled.  Chapter 8 of the Background Document
shows that potential emissions of VOCs from all substitutes for all end
uses in the refrigeration and air conditioning sector are likely to be
insignificant relative to VOCs from all other sources (i.e., other
industries, mobile sources, and biogenic sources).  Additional analysis
shows that even if all refrigerators produced by GE in one year were to
leak the maximum permissible leak per the standard UL 250 Supplement SA
over the course of the year (extremely unlikely), the resulting annual
VOC emissions would be less than 1x10-5 percent of all annual
anthropogenic VOC emissions.   Further, the calculated potential VOC
emissions due to use of isobutane in household refrigerators is less
than 1x10-4 percent of annual residential wood combustion emissions.
As these emissions of isobutane are several orders of magnitude less
than other anthropogenic emissions, including other residential
emissions (i.e., residential wood combustion), the environmental impacts
of these VOCs are not considered a threat.

8.  	REFERENCES

Calm, J.M. and G.C. Hourahan.  2007. “Refrigerant Data Update.”
Heating and Refrigerant Data Update.  79(1):50-64.  January 2007.

EPA 2008a.  Acute Exposure Guideline Levels: Definitions.  Accessed 27
February 2009.  Available at:
<http://www.epa.gov/opptintr/aegl/pubs/define.htm>.

EPA 2008b.  Volatile Organic Compounds – National Summary of VOC
Emissions.  Last updated 21 October 2008.  Accessed 4 March 2009.
Available at <http://www.epa.gov/air/emissions/voc.htm>.

EPA 1994.  Significant New Alternatives Policy Technical Background
Document:  Risk Screen on the Use of Substitutes for Class I
Ozone-depleting Substances: Refrigeration and Air Conditioning.
Stratospheric Protection Division.  March, 1994.

GE SNAP Submission. 2008. Significant New Alternatives Policy Program
Submission to the United States Environmental Protection Agency, October
2008.

ICF. 1997. Physiological Effects of Alternative Fire Protection Agents -
Hypoxic Atmospheres Conference. Stephanie Skaggs prepared the
proceedings of the conference held May 22, 1997 in New London, CT.

Kataoka.  1999.  “Allowable Charge Limit of Flammable Refrigerants and
Ventilation Requirements.”  Draft Proposal.  O. Kataoka/Daikin/Japan,
June, 1999.

Murray, D.M.  1997.  “Residential House and Zone Volumes in the United
States: Empirical and Estimated Parametric Distributions.”  Risk
Analysis.  17(4): 439-446.

NFPA.  2008.  NFPA 58: Liquefied Petroleum Gas Code.  National Fire
Protection Agency.

OSHA. 2004.  “Safety and Health Topics: Isobutane.”  February 2004.
Available online at:
<http://www.osha.gov/dts/chemicalsampling/data/CH_247840.html>.

Sheldon, L.S., et al.  1989. "An Investigation of Infiltration and
Indoor Air Quality."  New York State Energy Research & Development
Authority, Report 90-11.

 Fifty grams is the maximum permissible leak for refrigerants with
limits of flammability and heat of combustion greater than 19,000 kj/kg,
such as isobutane, per the standard UL 250 Supplement SA. Per this
standard, a larger charge is not prohibited, if the amount of
refrigerant leaked during testing does not exceed 50 grams.
Therefore, if a charge greater than 50 grams is to be used in these
refrigerators, the system should be designed to ensure that a
refrigerant leak would not exceed 50 grams.

 Murray (1997) uses data from the Brookhaven National Laboratory PFT
database.  Data regarding kitchen volumes were only available for the LA
area and the kitchen volumes are for a “kitchen zone” which may
include associated areas, such as utility rooms, dining rooms, living
rooms, and family room.  The inclusion of these other spaces in the
“kitchen zone” volume is realistic, as the presence of adjoining
rooms would increase the volume into which the refrigerant could leak.

 http://www.freepatentsonline.com/5259204.html

 http://www.freepatentsonline.com/6966365.html

 OSHA regulation 29 CFR 1910.110 considers ventilation adequate “when
the concentration of the gas in a gas-air mixture does not exceed 25
percent of the lower flammable limit.”

 Twelve percent oxygen in air is the No Observed Adverse Effect Level
(NOAEL) for hypoxia (ICF 1997).

 ICF International maintains the Vintaging Model for EPA in order to
simulate the aggregate impacts of the ODS phaseout on the use and
emissions of various fluorocarbons and their substitutes over a period
of several years across more than 40 different applications.  The model
tracks the use and emissions of various compounds for the annual
vintages of new equipment that enter service in each end-use.  The
vintage of each type of equipment determines such factors as leak rate,
charge size, number of units in operation, and the initial ODS substance
that the equipment contained.

 During disposal it is assumed that only 90 percent of the refrigerant
charge remains in the unit.

 Submission indicates this is the maximum number of days per year that
manufacturing will occur.

 Release scenarios include factory, on-site and recycling/salvage yard
releases, with and without recycling of the refrigerant.

 This figure determined using 2002 annual VOC emissions data from EPA
(2008b) and expected annual production levels from the GE SNAP
Submission (2008).

 This figure determined using 2002 annual VOC emissions data from EPA
(2008b).  Residential wood combustion is the only residential source
included in the EPA (2008b) analysis.

	          			                May 22, 2009


[Federal Register Volume 78, Number 76 (Friday, April 19, 2013)]
[Notices]
[Pages 23562-23563]
[FR Doc No: 2013-09294]

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

[FRL-9803-8]

Proposed Consent Decree, Clean Air Act Citizen Suit

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of proposed consent decree; request for public comment.

-----------------------------------------------------------------------

SUMMARY: In accordance with the Clean Air Act, as amended (``CAA''),
notice is hereby given of a proposed consent decree, to resolve a
lawsuit filed by Clean Air Council in the United States District Court
for the District of Columbia: Clean Air Council v. Jackson, No. 1:12-
cv-00707 (D. DC). On May 2, 2012, Plaintiff filed a complaint alleging
that EPA failed to promulgate a Federal Implementation Plan (``FIP'')
as mandated by the CAA, addressing certain nonattainment planning
provisions for the 1997 fine particulate matter National Ambient Air
Quality Standard (``NAAQS'') in the Commonwealth of Pennsylvania
(``Pennsylvania''). The complaint also alleges that EPA failed to make
a determination regarding whether the Liberty-Clairton nonattainment
area in Pennsylvania (``Liberty-Clairton Area'') has attained the 1997
fine particulate matter NAAQS by the applicable attainment date as
mandated by the CAA,. The proposed consent decree establishes deadlines
for EPA to take action.

DATES: Written comments on the proposed consent decree must be received
by May 20, 2013.

ADDRESSES: Submit your comments, identified by Docket ID number EPA-HQ-
OGC-2013-0234, online at www.regulations.gov (EPA's preferred method);
by email to<EMAIL_ADDRESS>mailed to EPA Docket Center,
Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania
Ave., NW., Washington, DC 20460-0001; or by hand delivery or courier to
EPA Docket Center, EPA West, Room 3334, 1301 Constitution Ave., NW.,
Washington, DC, between 8:30 a.m. and 4:30 p.m. Monday through Friday,
excluding legal holidays. Comments on a disk or CD-ROM should be
formatted in Word or ASCII file, avoiding the use of special characters
and any form of encryption, and may be mailed to the mailing address
above.

FOR FURTHER INFORMATION CONTACT: David Orlin, Air and Radiation Law
Office (2344A), Office of General Counsel, U.S. Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460;
telephone:<PHONE_NUMBER>; fax number<PHONE_NUMBER>; email address:
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

I. Additional Information About the Proposed Consent Decree

    The proposed consent decree would resolve a lawsuit filed by the
Clean Air Council seeking to compel the Agency to satisfy certain
mandatory duties under the Clean Air Act. Specifically the consent
decree provides for EPA to promulgate a FIP by December 15, 2013, for
the Liberty-Clairton Area including the following elements: an
attainment demonstration, emission inventory, reasonably available
control measures/reasonably available control technology (``RACM/
RACT''), reasonable further progress (``RFP''), and contingency
measures for the 1997 fine particulate matter annual NAAQS under CAA
section 110(c)(1)(A), 42 U.S.C. 7410(c)(1)(A). However, pursuant to CAA
section 110(k)(3), 42 U.S.C. 7410(k)(3), should EPA approve a state
implementation plan for the Liberty-Clairton Area to attain the 1997
fine particulate matter annual NAAQS for any of the elements listed
above, EPA's obligation to promulgate a federal implementation plan for
that element is void. In addition, should EPA make a determination that
the Liberty Clairton Area has attained the 1997 fine particulate matter
annual NAAQS prior to December 15, 2013 and has not revoked that
determination by December 15, 2013, the obligation to promulgate a FIP
for an attainment demonstration, reasonably available control measures/
reasonably available control technology (``RACM/RACT''), reasonable
further progress (``RFP''), and contingency measures is void. The
proposed consent decree also provides for EPA to make a determination
by December 15, 2013, as to whether the Liberty-Clairton Area attained
the 1997 fine particulate matter annual NAAQS by the applicable
attainment date, unless as of December 15, 2013, EPA has signed a final
notice extending the attainment deadline for the 1997 fine particulate
matter annual NAAQS for the Liberty-Clairton Area to a date after April
5, 2010.
    Under the proposed consent decree, within 15 business days
following signature of each final action described in the proposed
consent decree, EPA shall deliver the notice to the Office of the
Federal Register for review and publication in the Federal Register.
After EPA fulfills its obligations under the consent decree, the
consent decree provides that this case shall be dismissed with
prejudice.
    The proposed consent decree also states that the consent decree can
be modified by the parties, or by the court following a motion by a
party and a response thereto. In addition, the parties agree to seek to
resolve informally Clean Air Council's claim for litigation costs
pursuant to 42 U.S.C. 7604(d), but the court would retain jurisdiction
to resolve that claim.
    For a period of thirty (30) days following the date of publication
of this notice, the Agency will accept written comments relating to the
proposed consent decree from persons who were not named as parties or
intervenors to the litigation in question. EPA or the Department of
Justice may withdraw or withhold consent to the proposed consent decree
if the comments disclose facts or considerations that indicate that
such consent is inappropriate, improper, inadequate, or inconsistent
with the requirements of the Act. Unless EPA or the Department of
Justice determines that consent to this consent decree should be
withdrawn, the terms of the decree will be affirmed.

II. Additional Information About Commenting on the Proposed Consent
Decree

A. How can I get a copy of the consent decree?

    The official public docket for this action (identified by Docket ID
No. EPA-HQ-OGC-2013-0234) contains a copy of the proposed consent
decree (including Attachment A). The official public docket is
available for public viewing at the Office of Environmental Information
(OEI) Docket in the EPA Docket Center, EPA West, Room 3334, 1301
Constitution Ave. NW., Washington, DC. The EPA Docket Center 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<PHONE_NUMBER>, and the telephone number for the OEI
Docket is<PHONE_NUMBER>.
    An electronic version of the public docket is available through
www.regulations.gov. You may use the www.regulations.gov to submit or
view public comments, access the index listing of the contents of the
official public docket, and to access those documents in the public
docket that are available electronically. Once in the system, key in
the appropriate docket identification number then select ``search''.
    It is important to note that EPA's policy is that public comments,
whether

submitted electronically or in paper, will be made available for public
viewing online at www.regulations.gov without change, unless the
comment contains copyrighted material, CBI, or other information whose
disclosure is restricted by statute. Information claimed as CBI and
other information whose disclosure is restricted by statute is not
included in the official public docket or in the electronic public
docket. EPA's policy is that copyrighted material, including
copyrighted material contained in a public comment, will not be placed
in EPA's electronic public docket but will be available only in
printed, paper form in the official public docket. Although not all
docket materials may be available electronically, you may still access
any of the publicly available docket materials through the EPA Docket
Center.

B. How and to whom do I submit comments?

    You may submit comments as provided in the ADDRESSES section.
Please ensure that your comments are submitted within the specified
comment period. Comments received after the close of the comment period
will be marked ``late.'' EPA is not required to consider these late
comments.
    If you submit an electronic comment, EPA recommends that you
include your name, mailing address, and an email address or other
contact information in the body of your comment and with any disk or CD
ROM you submit. This ensures that you can be identified as the
submitter of the comment and allows EPA to contact you in case EPA
cannot read your comment due to technical difficulties or needs further
information on the substance of your comment. Any identifying or
contact information provided in the body of a comment will be included
as part of the comment that is placed in the official public docket,
and made available in EPA's electronic public docket. If EPA cannot
read your comment due to technical difficulties and cannot contact you
for clarification, EPA may not be able to consider your comment.
    Use of the www.regulations.gov Web site to submit comments to EPA
electronically is EPA's preferred method for receiving comments. The
electronic public docket system is an ``anonymous access'' system,
which means EPA will not know your identity, email address, or other
contact information unless you provide it in the body of your comment.
In contrast to EPA's electronic public docket, EPA's electronic mail
(email) system is not an ``anonymous access'' system. If you send an
email comment directly to the Docket without going through
www.regulations.gov, your email address is automatically captured and
included as part of the comment that is placed in the official public
docket, and made available in EPA's electronic public docket.

    Dated: April 8, 2013.
Lorie J. Schmidt,
Associate General Counsel.
[FR Doc. 2013-09294 Filed 4-18-13; 8:45 am]
BILLING CODE 6560-50-P