6560-50-P
ENVIRONMENTAL PROTECTION AGENCY
[EPA-R10-OAR-2024-0254; FRL-11982-01-R10]
Delegation of Authority to the State of Idaho to Implement or Enforce Additional or
Revised National Emission Standards for Hazardous Air Pollutants and New Source
Performance Standards
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of delegation of authority.
SUMMARY: On May 10, 2023, the Environmental Protection Agency (EPA) sent the State of
Idaho (Idaho) two letters acknowledging that Idaho’s delegation of authority to implement and
enforce the National Emissions Standards for Hazardous Air Pollutants (NESHAP) and New
Source Performance Standards (NSPS) had been updated. To inform regulated facilities and the
public, the EPA is, through this notice, making available a copy of the EPA’s letters to Idaho.
DATES: On May 10, 2023, the EPA sent Idaho two letters acknowledging that Idaho’s
delegation of authority to implement and enforce certain Federal NSPS and NESHAP had been
updated.
ADDRESSES: The EPA has established a docket for this action under Docket ID No. EPA–
R10–OAR–2024–0254. All documents, including the letters with enclosures sent to Idaho, in the
docket are listed on the https://www.regulations.gov website or are available for public
inspection during normal business hours at the Air and Radiation Division, U.S. Environmental
Protection Agency, Region 10, 1200 Sixth Avenue, Suite 155, Seattle, WA 98101-3144. Copies
of Idaho’s submittal are also available at the Idaho Department of Environmental Quality, 1410
N Hilton Street, Boise, ID 83706.
FOR FURTHER INFORMATION CONTACT: Bryan Holtrop, Air and Radiation Division,
U.S. EPA Region 10, 1200 Sixth Avenue, Suite 155, Seattle, WA 98101, (206) 553-4473 or
holtrop.bryan@epa.gov.

SUPPLEMENTARY INFORMATION:
I. Delegation of NESHAP
Section 112(l) of the Clean Air Act (CAA) provides for the regulation of hazardous air
pollutants through the promulgation of NESHAP. Those NESHAP promulgated prior to the
CAA Amendments of 1990 are found in 40 Code of Federal Regulations (CFR) part 61. Those
NESHAP promulgated subsequent to the CAA Amendments of 1990 are found in 40 CFR part
63. 40 CFR part 63 subpart E contains the criteria and procedures for “straight delegation”
(delegation of unchanged standards) of NESHAP. See 40 CFR 63.91.
On April 20, 2023, Idaho notified the EPA that the State had updated its incorporation by
reference of Federal NSPS and NESHAP to include many such standards, as they were published
in final form in the CFR dated July 1, 2022. On May 10, 2023, the EPA sent Idaho a letter
acknowledging that Idaho now has the authority to implement and enforce the NESHAP as
specified by Idaho in its notice to the EPA, as provided for under previously approved delegation
mechanisms. All notifications, applications, reports, and other correspondence required pursuant
to the delegated NESHAP must be submitted to both the EPA Region 10 and to the Idaho
Department of Environmental Quality, unless the delegated standard specifically provides that
such submittals may be sent to the EPA or a delegated State. In such cases, the submittals should
be sent only to the Idaho Department of Environmental Quality. A copy of the EPA’s letter to
Idaho follows:
“Ms. Tiffany Floyd
Air Quality Division Administrator
Idaho Department of Environmental Quality
1410 North Hilton
Boise, Idaho 83706
Re: Approval of the Idaho Department of Environmental Quality’s Request for Updated
Delegation of Authority for National Emissions Standards for Hazardous Air Pollutants
Dear Ms. Floyd:
This letter is in response to your April 20, 2023, request to update and continue the delegation of
certain National Emission Standards for Hazardous Air Pollutants. Consistent with the approved
mechanism for streamlined delegation as described in 67 FR 3106 (January 23, 2002), the U.S.

Environmental Protection Agency hereby grants this updated delegation request, as described
below, to the Idaho Department of Environmental Quality for those sources under your
jurisdiction for the identified NESHAP in effect on July 1, 2022.
Delegation Request
You have requested to update delegation of the 40 CFR parts 61 and 63 NESHAP standards that
were previously delegated to IDEQ and to obtain delegation of new standards that the EPA has
promulgated since your last delegation.
1. Your request for delegation of 40 CFR part 61, subpart M was limited to sources required to
obtain permits under title V of the Clean Air Act.
2. Your request for delegation excluded subparts under 40 CFR part 61 regulating radon or
radionuclides, specifically: subparts B, H, I, K, Q, R, T, and W.
3. Your request for delegation of all subparts of 40 CFR part 63 except N, AAAA, ZZZZ,
BBBBBB, HHHHHH, JJJJJJ, WWWWWW, XXXXXX, and DDDDDDD, was limited to
sources required to obtain permits under title V of the Clean Air Act.
IDEQ demonstrated that on March 28, 2023, IDEQ adopted the identified provisions of 40 CFR
parts 61 and 63 unchanged and as in effect on July 1, 2022, into IDEQ’s regulations in IDAPA
58.01.01.107.03(g) and (i).
Delegation of Authority
The EPA has determined that IDEQ’s regulations continue to provide adequate and effective
procedures for implementing and enforcing the NESHAP. Accordingly, the EPA hereby
approves your request for an updated delegation of authority to implement and enforce the
NESHAP standards identified in Enclosures A and B, subject to the following terms and
conditions:
1. As requested by IDEQ:
a. The delegation of 40 CFR part 61, subpart M and all subparts of 40 CFR part 63 except
N, AAAA, ZZZZ, BBBBBB, HHHHHH, JJJJJJ, WWWWWW, XXXXXX, and
DDDDDDD is limited to implementation and enforcement of the NESHAP as of July 1,
2022, and is limited to sources that are required to obtain a permit under Idaho’s title V
program, regardless of whether a permit has yet been issued.
b. The delegation of all other requested NESHAP is limited to implementation and
enforcement of the NESHAP as of July 1, 2022.
2. The EPA is not delegating the following provisions under 40 CFR part 63 to IDEQ:
a. Subpart B, which implements sections 112(g) and 112(j) of the Clean Air Act. The EPA
has previously stated that a part 70 permitting authority does not need to apply for
approval in order to use its own program to implement section 112(g). Furthermore,
section 112(j) is designed to use the title V permit process as the primary vehicle for
establishing requirements. Therefore, delegation is not required to implement sections
112(g) and 112(j) and 40 CFR subpart B. See 59 FR 26429, 26447 (May 20, 1994) and
61 FR 68384, 68397 (December 27, 1996).
b. Subpart C, which lists hazardous air pollutants that have been deleted or refined. This
subpart grants no authority that is necessary to implement or enforce the program and is
therefore not delegable.
c. Subpart D, which implements section 112(d) of the Clean Air Act. Because this subpart
explicitly states that it applies to a state or local agency acting pursuant to a permit
program approved under title V of the Clean Air Act, delegation is unnecessary.

d. Subpart E, which establishes procedures for the EPA approval of state rules, programs, or
other requirements to implement and enforce section 112 Federal rules and is not
delegable.
3. The EPA is not delegating the provisions of the Consolidated Air Rule under 40 CFR part 65.
As proposed on October 28, 1998 (63 FR 57748, 57784-57786) and promulgated on
December 14, 2000, (65 FR 78268, 78272), the CAR comprises alternative compliance
approaches to referencing subparts in 40 CFR parts 60 and 63. Therefore, formal delegation
of the CAR is not required provided the state has received formal delegation of the
referencing subpart.
4. Note that certain authorities are automatically granted to you because you have an approved
part 70 program (see for example, 40 CFR 63.6(i)(1)). See 66 FR 48211, 48213 (September
19, 2001). However, you must have authority to implement and enforce the particular
standard against the source as a matter of state law in order to implement this authority as a
matter of Federal law.
5. The EPA is delegating the identified Federal standards as in effect on July 1, 2022. New
NESHAP or NESHAP that are revised substantively after that date are not delegated to your
agency; these remain the responsibility of the EPA.
a. Acceptance of this delegation does not commit your agency to request or accept
delegation of future NESHAP standards and requirements.
b. The EPA encourages your agency to update your NESHAP delegation on an annual
basis. This could coincide with the updating of the adoption by reference of the Federal
NESHAP standards, which is important for maintaining the EPA’s approval of your part
70 permitting program.
6. The EPA is not delegating authorities under 40 CFR parts 61 and 63 that specifically indicate
they cannot be delegated, that require rulemaking to implement, that affect the stringency of
the standard, equivalency determinations, or where national oversight is the only way to
ensure national consistency.
7. The EPA is not delegating standards that have been vacated as a matter of Federal law.
8. This delegation is subject to the terms and conditions of the EPA’s previous NESHAP
delegations to IDEQ, 61 FR 64622 (December 6, 1996) and 67 FR 3106 (January 23, 2002),
as updated by this letter.
9. Implementation and enforcement of the delegated NESHAP are subject to the CAA 105 Air
Base Grant Agreement Workplan agreement between the state of Idaho and the EPA and its
successor documents. The Agreement defines roles and responsibilities, including timely and
appropriate enforcement response and the maintenance of the Integrated Compliance
Information System for Air via the Exchange Network.
10. Enforcement of these delegated NESHAP in your jurisdiction will be the primary
responsibility of your agency. Nevertheless, the EPA may exercise its concurrent
enforcement authority pursuant to sections 112(l)(7) and 113 of the Clean Air Act and 40
CFR 63.90(d)(2) with respect to sources that are subject to the NESHAP.
11. Your agency and the EPA should communicate sufficiently to ensure that each is fully
informed and current regarding interpretation of regulations (including any unique questions
about applicability) and the compliance status of subject sources in your jurisdiction.
a. Any records or reports provided to or otherwise obtained by your agency should be made
available to the EPA upon request.
b. In accordance with 40 CFR 61.16 and 63.15, the availability to the public of information
provided to or otherwise obtained by the EPA in connection with this delegation shall be
governed by 40 CFR part 2.
12. Your agency will be the recipient of all notifications and reports and be the point of contact
for questions and compliance issues for these delegated NESHAP. The EPA may request
notifications and reports from owners/operators and/or your agency, if needed.

13. Your agency will work with owners and operators of affected facilities subject to a NESHAP
subpart to ensure all required information is submitted to your agency. Your assistance is
requested to ensure that this information, including excess emission reports and summaries,
is submitted to the EPA upon request, if needed.
14. Your agency will require affected facilities to use the methods specified in 40 CFR parts 61
and 63, as applicable, in performing source tests pursuant to the regulations. See 40 CFR 61.7
and 63.7.
15. Changes and alternatives:
a. For part 61 standards, your agency is not delegated the authorities under 40 CFR
61.04(b), 61.04(c), 61.05(c), 61.11, 61.12(d), 61.13(h)(1)(ii), 61.14(d), 61.14(g)(1)(ii),
and 61.16. Such authorities and approvals remain the responsibility of the EPA.
b. For part 63 standards, your agency is not delegated the Category II authorities in 40 CFR
63.91(g)(2)(ii). Such authorities and approvals remain the responsibility of the EPA.
c. Your agency must maintain a record of all approved alternatives to monitoring, testing,
and recordkeeping/reporting requirements and provide this list of alternatives to the EPA
semi-annually or more frequently if requested by the EPA. The EPA may audit any
approved alternatives and disapprove any that it determines are inappropriate, after
discussion with your agency. If changes are disapproved, your agency must notify the
owner/operator that it must revert to the original applicable monitoring, testing,
recordkeeping, and/or reporting requirements. Also, in cases where the owner/operator
does not maintain the conditions which prompted the approval of the alternatives to the
monitoring, testing, recordkeeping, and/or reporting requirements, your agency must
require the source to revert to the original monitoring, testing, recordkeeping, and
reporting requirements, or more stringent requirements, if justified.
16. Your agency’s authority to implement and enforce NESHAP under this delegation does not
extend to sources or activities located in Indian Country, as defined in 18 U.S.C. 1151.
Consistent with previous Federal program approvals or delegations, the EPA will continue to
implement the NESHAP in Indian Country because your agency has not demonstrated that it
has authority over sources and activities located within the exterior boundaries of Indian
reservations and in other areas of Indian Country.
17. The EPA Administrator delegated to the EPA, Region 10 the authority to delegate the
NESHAP to any state or local agency. A state or local agency that receives delegation from
the EPA, Region 10 does not have the federally recognized authority to further delegate the
NESHAP.
18. 40 CFR 63.96(b) contains the applicable procedures governing withdrawal of this delegation
by the EPA or from this delegation by IDEQ, as applicable.
Unless we receive negative comments from you within ten days, this delegation is final and will
be effective ten days from the date of this letter. Otherwise, no further correspondence to the
EPA is needed from IDEQ to make this delegation effective. We will periodically publish a
notice in the Federal Register informing the public of IDEQ’s updated delegation. If you have
any questions, please contact Geoffrey Glass of my staff at (206) 553-1847 or
glass.geoffrey@epa.gov.
Sincerely,
Krishna Viswanathan, Director
Air and Radiation Division”
II. Delegation of NSPS
Section 111(b) of the CAA requires the EPA to establish standards of performance for

new stationary sources of air pollution through the promulgation of NSPS. These NSPS are
found in 40 CFR part 60. According to section 111(c) of the CAA and 40 CFR 60.4(b), States
may submit plans for approval by the Administrator to implement and enforce NSPS. Neither
section 111 of the CAA nor 40 CFR part 60, however, prescribe a mechanism for such a
delegation of authority.
On April 20, 2023, Idaho notified the EPA that the State had updated its incorporation by
reference of Federal NSPS to include many such standards, as they were published in final form
in the Code of Federal Regulations (CFR) dated July 1, 2022. On May 10, 2023, the EPA sent
Idaho a letter acknowledging that Idaho now has the authority to implement and enforce the
NSPS as specified by Idaho in its notice to the EPA, as provided for under previously approved
delegation mechanisms. All notifications, applications, reports, and other correspondence
required pursuant to the delegated NSPS must be submitted to both the EPA Region 10 and to
the Idaho Department of Environmental Quality, unless the delegated standard specifically
provides that such submittals may be sent to the EPA or a delegated State. In such cases, the
submittals should be sent only to the Idaho Department of Environmental Quality. A copy of the
EPA’s letter to Idaho follows:
“Ms. Tiffany Floyd
Air Quality Division Administrator
Idaho Department of Environmental Quality
1410 North Hilton
Boise, Idaho 83706
Re: Approval of the Idaho Department of Environmental Quality’s Request for Updated
Delegation of Authority for New Source Performance Standards
Dear Ms. Floyd:
This letter is in response to your April 20, 2023, request to update and continue the delegation of
authority to implement and enforce certain New Source Performance Standards, 40 CFR part 60.
After review of your request, the U.S. Environmental Protection Agency hereby grants this
updated delegation request, as described below, to the Idaho Department of Environmental
Quality for those sources under your jurisdiction for the identified NSPS in effect on July 1,
2022.
Delegation Request

You have requested to update delegation of the 40 CFR part 60 NSPS that were previously
delegated to IDEQ and to obtain delegation of new standards that the EPA has promulgated since
your last delegation.
IDEQ demonstrated that on March 28, 2023, IDEQ adopted the identified provisions of 40 CFR
part 60 unchanged and as in effect on July 1, 2022, into IDEQ’s regulations in IDAPA
58.01.01.107.03(f).
Delegation of Authority
The EPA has determined that IDEQ’s regulations continue to provide adequate and effective
procedures for implementing and enforcing the NSPS. Accordingly, the EPA hereby approves
your request for an updated delegation of authority to implement and enforce the NSPS
identified in Enclosure A, subject to the following terms and conditions:
1. As requested by IDEQ the delegation of all requested NSPS is limited to implementation and
enforcement of the NSPS as of July 1, 2022.
2. The EPA is not delegating the following provisions under 40 CFR part 60 to IDEQ:
a. Subparts B and Ba, which apply to the adoption and submittal of state plans and actions
taken to approve or disapprove such plans by the Administrator of the EPA. These
subparts are not delegable.
b. Subpart C, which states that several other subparts contain emission guidelines and
compliance times for the control of certain designated pollutants in accordance with
section 111(d) and section 129 of the Clean Air Act and subpart B of 40 CFR part 60.
This subpart establishes no authority that is necessary to implement or enforce the
program and is not delegable.
c. Subparts Cb, Cc, Cd, Ce, Cf, BBBB, DDDD, FFFF, MMMM, and UUUUa. These
subparts specify the requirements for approval of state plans for the control of certain
designated pollutants in accordance with section 111(d) and section 129 of the Clean Air
Act and subpart B or Ba of 40 CFR part 60.
3. The EPA is not delegating the provisions of the Consolidated Air Rule under 40 CFR part 65.
As proposed on October 28, 1998, (63 FR 57748, 57784-57786) and promulgated on
December 14, 2000, (65 FR 78268, 78272), the CAR comprises alternative compliance
approaches to referencing subparts in 40 CFR parts 60 and 63. Therefore, formal delegation
of the CAR is not required provided the state has received formal delegation of the
referencing subpart.
4. The EPA is delegating the identified Federal standards as in effect on July 1, 2022. New
NSPS or NSPS that are revised substantively after that date are not delegated to your agency;
these remain the responsibility of the EPA.
a. Acceptance of this delegation does not commit your agency to request or accept
delegation of future NSPS standards and requirements.
b. The EPA encourages your agency to update your NSPS delegation on an annual basis.
This could coincide with the updating of the adoption by reference of the Federal NSPS
standards, which is important for maintaining the EPA’s approval of your part 70
permitting program.
5. The EPA is not delegating authorities under 40 CFR part 60 that specifically indicate they
cannot be delegated, that require rulemaking to implement, that affect the stringency of the
standard, equivalency determinations, or where national oversight is the only way to ensure
national consistency.
6. The EPA is not delegating standards that have been vacated as a matter of Federal law.
7. Implementation and enforcement of the delegated NSPS are subject to the CAA 105 Air Base
Grant Agreement Work Plan between the state of Idaho and the EPA and its successor

documents. The agreement defines roles and responsibilities, including timely and
appropriate enforcement response and the maintenance of the Integrated Compliance
Information System for Air via the Exchange Network. Your agency will ensure that all
relevant source notification and report information is entered as provided in the agreement
into the specified EPA database system to meet your recordkeeping/reporting requirements.
8. Enforcement of these delegated NSPS in your jurisdiction will be the primary responsibility
of your agency. Nevertheless, the EPA may exercise its concurrent enforcement authority
pursuant to sections 111(d)(2) and 113 of the Clean Air Act with respect to sources that are
subject to the NSPS.
9. Your agency and the EPA should communicate sufficiently to ensure that each is fully
informed and current regarding interpretation of regulations (including any unique questions
about applicability) and the compliance status of subject sources in your jurisdiction.
a. Any records or reports provided to or otherwise obtained by your agency should be made
available to the EPA upon request.
b. In accordance with 40 CFR 60.9, the availability to the public of information provided to
or otherwise obtained by the EPA in connection with this delegation shall be governed by
40 CFR part 2.
10. Your agency will be the recipient of all notifications and reports and be the point of contact
for questions and compliance issues for these delegated NSPS. The EPA may request
notifications and reports from owners/operators and/or your agency, if needed.
11. Your agency will work with owners and operators of affected facilities subject to an NSPS
subpart to ensure all required information is submitted to your agency. Your assistance is
requested to ensure that this information, including excess emission reports and summaries,
is submitted to the EPA upon request, if needed.
12. Your agency will require affected facilities to use the methods specified in 40 CFR part 60,
as applicable, in performing source tests pursuant to the regulations. See 40 CFR 60.8.
13. Changes and alternatives:
a. Your agency is not delegated the authorities under 40 CFR 60.4(b), 60.8(b) (terms 2 and
3, to the extent that the change represents an alternative or equivalent method or a major
change to testing as defined in 40 CFR 63.90), 60.9, 60.11(b) (with respect to alternative
methods), 60.11(e)(7)&(8), 60.13(a), 60.13(d)(2), and 60.13(g). Such authorities and
approvals remain the responsibility of the EPA.
b. Your agency is not delegated the authority to approve a major change to monitoring
under 40 CFR 60.13(i). A major change to monitoring is defined in 40 CFR 63.90.
c. Your agency must maintain a record of all approved alternatives to monitoring, testing,
and recordkeeping/reporting requirements and provide this list of alternatives to the EPA
semi-annually or more frequently if requested by the EPA. The EPA may audit any
approved alternatives and disapprove any that it determines are inappropriate, after
discussion with your agency. If changes are disapproved, your agency must notify the
owner/operator that it must revert to the original applicable monitoring, testing,
recordkeeping, and/or reporting requirements. Also, in cases where the owner/operator
does not maintain the conditions which prompted the approval of the alternatives to the
monitoring, testing, recordkeeping, and/or reporting requirements, your agency must
require the owner/operator to revert to the original monitoring, testing, recordkeeping,
and reporting requirements, or more stringent requirements, if justified.
14. Your agency’s authority to implement and enforce NSPS under this delegation does not
extend to sources or activities located in Indian Country, as defined in 18 U.S.C. 1151.
Consistent with previous Federal program approvals or delegations, the EPA will continue to
implement the NSPS in Indian Country because your agency has not demonstrated authority
over sources and activities located within the exterior boundaries of Indian reservations and
in other areas of Indian Country.

15. The EPA Administrator delegated to the EPA, Region 10 the authority to delegate the NSPS
to any state or local agency. A state or local agency that receives delegation from the EPA,
Region 10 does not have the federally recognized authority to further delegate the NSPS.
16. If the EPA determines that your agency’s procedures for implementing or enforcing the
NSPS are inadequate or are not being effectively carried out, this delegation may be revoked
in whole or in part by written notice of the revocation. Any such revocation will be effective
as of the date specified in the notice.
Unless we receive negative comments from you within ten days, this delegation is final and will
be effective ten days from the date of this letter. Otherwise, no further correspondence to the
EPA is needed from IDEQ to make this delegation effective. We will periodically publish a
notice in the Federal Register informing the public of IDEQ’s updated delegations. If you have
any questions, please contact Geoffrey Glass of my staff at (206) 553-1847 or
glass.geoffrey@epa.gov.
Sincerely,
Krishna Viswanathan, Director
Air and Radiation Division”
This notice acknowledges the update of Idaho’s delegation of authority to implement and enforce
NSPS and NESHAP.
Dated: July 9, 2024.
Krishnaswamy Viswanathan,
Director, Air and Radiation Division, Region 10.
[FR Doc. 2024-15395 Filed: 7/12/2024 8:45 am; Publication Date: 7/15/2024]