[Code of Federal Regulations]
[Title 40, Volume 5]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR57.402]

[Page 143-146]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 57--PRIMARY NONFERROUS SMELTER ORDERS--Table of Contents
 
          Subpart D--Supplementary Control System Requirements
 
Sec. 57.402  Elements of the supplementary control system.

    Each supplementary control system shall contain the following 
elements:
    (a) Air quality monitoring network. An approvable SCS shall include 
the use of appropriate ambient air quality monitors to continuously 
measure the concentration of sulfur dioxide in the air in the smelter's 
DLA.
    (1) The monitors shall be located at all points of expected 
SO2 concentrations necessary to anticipate and prevent 
possible violations of NAAQS anywhere in the smelter's DLA. The 
determination of the locations where such concentrations may occur shall 
take into account all recorded or probable meteorological and operating 
conditions (including bypassing of control equipment), as well as the 
presence of other sources of SO2 significantly affecting 
SO2 concentrations in the DLA.
    (2) The number and location of sites shall be based on dispersion 
modeling, measured ambient air quality data,

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meteorological information, and the results of the continuing review 
required by paragraph (f) of this section. The system shall include the 
use of at least 7 fixed monitors unless the issuing agency determines, 
on the basis of a demonstration by the smelter owner, that the use of 
fewer monitors would not limit coverage of points of high SO2 
concentration or otherwise reduce the capability of the smelter owner to 
prevent any violations of the NAAQS in the smelter's DLA.
    (3) All monitors shall be continuously operated and maintained and 
shall meet the performance specifications contained in 40 CFR part 53. 
The monitors shall be capable of routine real time measurement of 
maximum expected SO2 concentrations for the averaging times 
of SO2 NAAQS.
    (b) Meteorological network. The SCS must have a meteorological 
assessment capability adequate to predict and identify local conditions 
requiring emission curtailment to prevent possible violations of the 
NAAQS. The meteorological assessment capability shall provide all 
forecast and current information necessary for successful use of the SCS 
operational manual required by paragraph (e) of this section.
    (c) Designated liability area. The system shall be required to 
prevent all violations of the NAAQS within the smelter's DLA. The DLA of 
any smelter is the area within which the smelter's emissions may cause 
or significantly contribute to violations of the NAAQS for 
SO2 when the smelter is operating at its maximum production 
capacity under any recorded or probable meterological conditions. The 
boundaries of that area shall be specified in the NSO.
    (1) Unless an acceptable demonstration is made under paragraph 
(c)(2) of this section, the DLA shall be a circle with a center point at 
the smelter's tallest stack and a minimum radius as given in the 
following table:

       Radius for SO2 Emissions at Maximum Production Capacity \1\
------------------------------------------------------------------------
                                         Emission rate in      Radius in
   Emissions rate in tons per hour        grains per sec.     kilometers
------------------------------------------------------------------------
16 or less..........................  4,000 or less.........         11
24..................................  6,000.................         16
32..................................  8,000.................         24
40..................................  10,000................         32
48 or more..........................  12,000 or more........         40
------------------------------------------------------------------------
\1\ Maximum emission rates for periods not to exceed 24 hours. Minimum
  radii may be determined from the table by linear interpolation.

    (2) The NSO may provide for a DLA with different boundaries if the 
smelter owner can demonstrate through the use of appropriate dispersion 
modeling and ambient air quality monitoring data that the smelter's 
controlled emissions could not cause or significantly contribute to a 
violation of the NAAQS beyond the boundaries of such a different area 
under any recorded or probable meteorological conditions.
    (3) A violation of the NAAQS in the DLA of any smelter shall 
constitute a violation of that smelter's NSO, unless the issuing agency 
determines on the basis of a showing by the smelter owner that the 
smelter owner had taken all emission curtailment action indicated by the 
SCS operational manual and that the violation was caused in significant 
part by:
    (i) Emissions of another source(s) which were in excess of the 
maximum permissible emissions applicable to such source(s),
    (ii) Fugitive emissions of another source(s), or
    (iii) The smelter's own fugitive emissions: Provided, that the 
smelter is in compliance with all requirements of or under subpart E of 
this part.
    (4) For the purposes of this section, maximum permissible emissions 
for other sources are the highest of:
    (i) SIP emission limitation;
    (ii) Orders in effect under section 113(d) of the Clean Air Act; or
    (d) Overlapping designated liability areas. Notwithstanding any 
other provisions of this subpart, the following requirements shall apply 
whenever the designated liability areas of 2 or more smelters do, or 
may, overlap:
    (1) In the case of any NSO applicant that would have a DLA which 
would overlap with the DLA of any other smelter that has applied for an 
NSO or has an NSO in effect, the NSO applicant shall include in its 
application an enforceable joint plan, agreed to by

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such other smelter(s). In determining whether a joint plan is required, 
the NSO applicant shall calculate its DLA according to the table in 
paragraph (c)(1) of this section. The DLA of the other smelter shall be 
calculated according to the table in paragraph (c)(1) unless the other 
smelter has an NSO in effect, in which case the boundaries in that NSO 
shall be used. The enforceable joint plan shall provide for:
    (i) Emission curtailment adequate to ensure that the NAAQS will not 
be violated in any areas of overlapping DLAs; and
    (ii) Conclusive prospective allocation of legal liability in the 
event that the NAAQS are violated in the area of overlapping DLAs.

Such plans may, but need not, include the operation of a joint SCS 
system. Each NSO shall require adherence by the NSO applicant owner to 
the joint plan for emission curtailment and allocation of liability, 
unless the issuing agency determines, pursuant to the provisions of 
paragraph (c)(2) of this section, that the NSO applicant's DLA does not 
overlap with that of any other smelter.
    (2) In the case of any NSO applicant that would have a DLA which 
would overlap with the DLA of any other smelter whose owner has not 
applied for an NSO (and does not have an NSO in effect), the NSO 
applicant's submittal shall contain a written consent, signed by a 
corporate official empowered to do so. The consent shall state that if, 
at any time thereafter, the owner of the other smelter applies for an 
NSO, and the other smelter's DLA would overlap with the NSO applicant's 
DLA, the NSO applicant will negotiate and submit an enforceable joint 
plan for emission curtailment and allocation of liability (as described 
in paragraph (d)(1) of this section). In determining whether it is 
necessary to submit such a consent, each smelter's DLA shall be 
calculated according to the table set forth in paragraph (c)(1) of this 
section. The consent shall state that a joint plan shall be submitted 
within 90 days of the issuing agency's notification to the NSO applicant 
of receipt of the other smelter's letter of intent, unless the issuing 
agency determines that the DLAs do not overlap. Failure of the NSO 
applicant to submit such a plan shall constitute grounds for denial of 
its NSO application or a violation of an effective NSO, as applicable.
    (e) The SCS operational manual. Each NSO shall require the smelter 
to be operated in accordance with the provisions of an SCS operational 
manual approved by the issuing agency. The SCS operational manual shall 
describe the circumstances under which, the extent to which, and the 
procedures through which emissions shall be curtailed to prevent 
violations of the NAAQS in the smelter's DLA. Failure to curtail 
emissions when and as much as indicated by the manual or to follow the 
provisions of the manual implementing the requirements of paragraph 
(e)(3) of this section shall constitute a violation of the NSO.
    (1) The operational manual shall prescribe emission curtailment 
decisions based on the use of real time information from the air quality 
monitoring network dispersion model estimates of the effect of emissions 
on air quality, and meteorological observations and predictions.
    (2) The operational manual shall also provide for emission 
curtailment to prevent violation of the NAAQS within the smelter's DLA 
which may be caused in part by stack emissions, and to the extent 
practicable fugitive emissions, from any other source (unless that other 
source is a smelter subject to an NSO).
    (3) The SCS operational manual shall include (but not be limited 
to):
    (i) A clear delineation of the authority of the SCS operator to 
require all other smelter personnel to implement the operator's 
curtailment decisions;
    (ii) The maintenance and calibration procedures and schedules for 
all SCS equipment;
    (iii) A description of the procedures to be followed for the regular 
acquisition of all meteorological information necessary to operate the 
system;
    (iv) The ambient concentrations and meteorological conditions that 
will be used as criteria for determining the need for various degrees of 
emission curtailment;
    (v) The meteorological variables as to which judgments may be made 
in

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applying the criteria stated pursuant to paragraph (e)(3)(iv) of this 
section;
    (vi) The procedures through which and the maximum time period within 
which a curtailment decision will be made and implemented by the SCS 
operator;
    (vii) The method for immediately evaluating the adequacy of a 
particular curtailment decision, including the factors to be considered 
in that evaluation;
    (viii) The procedures through which and the time within which 
additional necessary curtailment will immediately be effected; and
    (ix) The procedures to be followed to protect the NAAQS in the event 
of a mechanical failure in any element of the SCS.
    (f) Continuing review and improvement of the SCS. Each NSO shall 
require the smelter owner to conduct an active program to continuously 
review the design and operation of the SCS to determine what measures 
may be available for improving the performance of the system. Among the 
elements of this program shall be measures to locate and examine 
possible places both inside and outside the DLA where unmonitored NAAQS 
violations may be occurring. Such measures shall include the use of 
modeling as appropriate and mobile ambient air quality monitors, 
following up on information and complaints from members of the public, 
and other appropriate activities. The NSO shall also require the 
submission of a semi-annual report to the issuing agency detailing the 
results of this review and specifying measures implemented to prevent 
the recurrence of any violations of NAAQS.