I 
119TH CONGRESS 
1ST SESSION 
H. R. 161 
To amend sections 111, 169, and 171 of the Clean Air Act to clarify 
when a physical change in, or change in the method of operation of, 
a stationary source constitutes a modification or construction, and for 
other purposes. 
IN THE HOUSE OF REPRESENTATIVES 
JANUARY 3, 2025 
Mr. GRIFFITH introduced the following bill; which was referred to the 
Committee on Energy and Commerce 
A BILL 
To amend sections 111, 169, and 171 of the Clean Air 
Act to clarify when a physical change in, or change 
in the method of operation of, a stationary source con-
stitutes a modification or construction, and for other 
purposes. 
Be it enacted by the Senate and House of Representa-
tives of the United States of America in Congress assembled, 
SECTION 1. SHORT TITLE. 
This Act may be cited as the ‘‘New Source Review 
Permitting Improvement Act’’. 
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SEC. 2. CLARIFICATION OF DEFINITION OF A MODIFICA-
TION: EMISSION RATE INCREASES, POLLU-
TION CONTROL, EFFICIENCY, SAFETY, AND 
RELIABILITY PROJECTS. 
Paragraph (4) of section 111(a) of the Clean Air Act 
(42 U.S.C. 7411(a)) is amended— 
(1) by inserting ‘‘(A)’’ before ‘‘The term’’; 
(2) by inserting before the period at the end the 
following: ‘‘. For purposes of the preceding sentence, 
a change increases the amount of any air pollutant 
emitted by such source only if the maximum hourly 
emission rate of an air pollutant that is achievable 
by such source after the change is higher than the 
maximum hourly emission rate of such air pollutant 
that was achievable by such source during any hour 
in the 10-year period immediately preceding the 
change’’; and 
(3) by adding at the end the following: 
‘‘(B) Notwithstanding subparagraph (A), the 
term ‘modification’ does not include a change at a 
stationary source that is designed— 
‘‘(i) to reduce the amount of any air pol-
lutant emitted by the source per unit of produc-
tion; or 
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‘‘(ii) to restore, maintain, or improve the 
reliability of operations at, or the safety of, the 
source, 
except, with respect to either clause (i) or (ii), when 
the change would be a modification as defined in 
subparagraph (A) and the Administrator determines 
that the increase in the maximum achievable hourly 
emission rate of a pollutant from such change would 
cause an adverse effect on human health or the envi-
ronment.’’. 
SEC. 3. CLARIFICATION OF DEFINITION OF CONSTRUCTION 
FOR PREVENTION OF SIGNIFICANT DETERIO-
RATION. 
Subparagraph (C) of section 169(2) of the Clean Air 
Act (42 U.S.C. 7479(2)) is amended to read as follows: 
‘‘(C) The term ‘construction’, when used in con-
nection with a major emitting facility, includes a 
modification (as defined in section 111(a)) at such 
facility, except that for purposes of this subpara-
graph a modification does not include a change at 
a major emitting facility that does not result in a 
significant emissions increase, or a significant net 
emissions increase, in annual actual emissions at 
such facility.’’. 
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SEC. 4. CLARIFICATION OF DEFINITION OF MODIFICA-
TIONS AND MODIFIED FOR NONATTAINMENT 
AREAS. 
Paragraph (4) of section 171 of the Clean Air Act 
(42 U.S.C. 7501) is amended to read as follows: 
‘‘(4) The terms ‘modifications’ and ‘modified’ 
mean a modification as defined in section 111(a)(4), 
except that such terms do not include a change at 
a major emitting facility that does not result in a 
significant emissions increase, or a significant net 
emissions increase, in annual actual emissions at 
such facility.’’. 
SEC. 5. RULE OF CONSTRUCTION. 
Nothing in this Act or the amendments made by this 
Act shall be construed to treat any change as a modifica-
tion for purposes of any provision of the Clean Air Act 
(42 U.S.C. 7401 et seq.) if such change would not have 
been so treated as of the day before the date of enactment 
of this Act. 
Æ 
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