Proposed Rule2026-20468
Initial Air Quality Designations for the 2024 Revised Primary Annual Fine Particle (PM2.5) National Ambient Air Quality Standards (NAAQS)
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
October 6, 2026
Issuing agencies
Environmental Protection Agency
Abstract
The U.S. Environmental Protection Agency (EPA) is providing notice of the Agency's intended approach for area designations for the 2024 primary annual fine particulate matter (PM<INF>2.5</INF>) National Ambient Air Quality Standard (NAAQS) (the 2024 annual PM<INF>2.5</INF> NAAQS) under Clean Air Act (CAA) section 107(d). Details regarding these designations, as well as the EPA's notifications to States, territories, and Tribes regarding their initial area designations are accessible via the Agency's website and public electronic docket. With this notice, the EPA is providing an opportunity for public comment on its intended approach for finalizing area designations during the comment period specified in the DATES section. The EPA sent notifications directly to applicable States, territories, and Tribes regarding their initial area designations on or about October 2, 2026, and anticipates promulgating final designations consistent with CAA requirements.
Full Text
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<title>Federal Register, Volume 91 Issue 192 (Tuesday, October 6, 2026)</title>
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[Federal Register Volume 91, Number 192 (Tuesday, October 6, 2026)]
[Proposed Rules]
[Pages 63516-63519]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-20468]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 81
[EPA-HQ-OAR-2024-0078; FRL-11650-03-OAR]
RIN 2060-AW33
Initial Air Quality Designations for the 2024 Revised Primary
Annual Fine Particle (PM2.5) National Ambient Air Quality Standards
(NAAQS)
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of availability; opportunity for public comment.
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SUMMARY: The U.S. Environmental Protection Agency (EPA) is providing
notice of the Agency's intended approach for area designations for the
2024 primary annual fine particulate matter (PM<INF>2.5</INF>) National
Ambient Air Quality Standard (NAAQS) (the 2024 annual PM<INF>2.5</INF>
NAAQS) under Clean Air Act (CAA) section 107(d). Details regarding
these designations, as well as the EPA's notifications to States,
territories, and Tribes regarding their initial area designations are
accessible via the Agency's website and public electronic docket. With
this notice, the EPA is providing an opportunity for public comment on
its intended approach for finalizing area designations during the
comment period
[[Page 63517]]
specified in the DATES section. The EPA sent notifications directly to
applicable States, territories, and Tribes regarding their initial area
designations on or about October 2, 2026, and anticipates promulgating
final designations consistent with CAA requirements.
DATES: Comments must be received on or before November 5, 2026.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2024-0078, by any of the following methods:
<bullet> Federal eRulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>
(the EPA's preferred method). Follow the online instructions for
submitting comments.
<bullet> Email: <a href="/cdn-cgi/l/email-protection#4b2a662a252f6639662f2428202e3f0b2e3b2a652c243d"><span class="__cf_email__" data-cfemail="c2a3efa3aca6efb0efa6ada1a9a7b682a7b2a3eca5adb4">[email protected]</span></a>. Include Docket ID No. EPA-
HQ-OAR-2024-0078 in the subject line of the message.
<bullet> Mail: U.S. Environmental Protection Agency, EPA Docket
Center, Office Air and Radiation Docket, Mail Code 28221T, 1200
Pennsylvania Avenue NW, Washington, DC 20460.
<bullet> Hand Delivery or Courier (by scheduled appointment only):
EPA Docket Center, WJC West Building, Room 3334, 1301 Constitution
Avenue NW, Washington, DC 20004. The Docket Center's hours of
operations are 8:30 a.m.-4:30 p.m., Monday-Friday (except Federal
holidays).
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received may be posted without change
to <a href="https://www.regulations.gov">https://www.regulations.gov</a>, including any personal information
provided. For detailed instructions on sending comments and additional
information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document. For information on EPA Docket
Center services, please visit us online at <a href="https://www.epa.gov/dockets">https://www.epa.gov/dockets</a>.
FOR FURTHER INFORMATION CONTACT: For information on this notice of data
availability, contact Gabrielle Deabler, U.S. Environmental Protection
Agency, Office of State Air Partnerships, Air Quality Planning
Division, P.O. Box 12055, Mail Code: C541G, Research Triangle Park, NC
27709; telephone number: (919) 541-5766; email address:
<a href="/cdn-cgi/l/email-protection#d5b1b0b4b7b9b0a7fbb2b4b7a7bcb0b9b9b095b0a5b4fbb2baa3"><span class="__cf_email__" data-cfemail="63070602010f06114d040201110a060f0f06230613024d040c15">[email protected]</span></a> or Andrew Leith, U.S. Environmental
Protection Agency, Office of State Air Partnerships, Air Quality
Planning Division, P.O. Box 12055, Mail Code: C541D, Research Triangle
Park, NC 27709; telephone number: (919) 541-1069; email address:
<a href="/cdn-cgi/l/email-protection#92fef7fbe6fabcf3fcf6e0f7e5d2f7e2f3bcf5fde4"><span class="__cf_email__" data-cfemail="85e9e0ecf1edabe4ebe1f7e0f2c5e0f5e4abe2eaf3">[email protected]</span></a>.
Regional Office Contacts
The following serve as points of contact for inquiries related to
specific areas within the respective EPA Regional offices. The
information can also be reviewed online at <a href="https://www.epa.gov/particle-pollution-designations">https://www.epa.gov/particle-pollution-designations</a> and in the public docket for these 2024
annual PM<INF>2.5</INF> NAAQS designations at <a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket ID No. EPA-HQ-OAR-2024-0078.
____________________________________
EPA regional office contacts Affected states
____________________________________
EPA Region 1, Lynne Hamjian, CT, ME, MA, NH, RI, VT.
<a href="/cdn-cgi/l/email-protection#2e664f4344474f4000625740404b6e4b5e4f00494158"><span class="__cf_email__" data-cfemail="eda58c8087848c83c3a194838388ad889d8cc38a829b">[email protected]</span></a>.
EPA Region 2, Richard Ruvo, NJ, NY, Puerto Rico, U.S.
<a href="/cdn-cgi/l/email-protection#95c7e0e3fabbc7fcf6fdf4e7f1d5f0e5f4bbf2fae3"><span class="__cf_email__" data-cfemail="8ddff8fbe2a3dfe4eee5ecffe9cde8fdeca3eae2fb">[email protected]</span></a>. Virgin Islands.
EPA Region 3, Michael Dunn, DE, DC, MD, PA, VA, WV.
<a href="/cdn-cgi/l/email-protection#397d4c57571774505a51585c55795c4958175e564f"><span class="__cf_email__" data-cfemail="c98dbca7a7e784a0aaa1a8aca589acb9a8e7aea6bf">[email protected]</span></a>.
EPA Region 4, Denisse Diaz, AL, FL, GA, KY, MS, NC, SC, TN.
<a href="/cdn-cgi/l/email-protection#f2b69b9388dcb6979c9b818197b2978293dc959d84"><span class="__cf_email__" data-cfemail="47032e263d690322292e3434220722372669202831">[email protected]</span></a>.
EPA Region 5, John Mooney, IL, IN, MI, MN, OH, WI.
<a href="/cdn-cgi/l/email-protection#8dc0e2e2e3e8f4a3c7e2e5e3cde8fdeca3eae2fb"><span class="__cf_email__" data-cfemail="4f022020212a3661052027210f2a3f2e61282039">[email protected]</span></a>.
EPA Region 6, James McDonald, AR, LA, NM, OK, TX.
<a href="/cdn-cgi/l/email-protection#c78aa483a8a9a6aba3e98da6aaa2b487a2b7a6e9a0a8b1"><span class="__cf_email__" data-cfemail="9ed3fddaf1f0fff2fab0d4fff3fbeddefbeeffb0f9f1e8">[email protected]</span></a>.
EPA Region 7, Dana Skelley, IA, KS, MO, NE.
<a href="/cdn-cgi/l/email-protection#f8ab939d94949d81d6bc999699b89d8899d69f978e"><span class="__cf_email__" data-cfemail="025169676e6e677b2c46636c63426772632c656d74">[email protected]</span></a>.
EPA Region 8, Adrienne Sandoval, CO, MT, ND, SD, UT, WY.
<a href="/cdn-cgi/l/email-protection#7526141b111a0314195b3411071c101b1b10351005145b121a03"><span class="__cf_email__" data-cfemail="085b69666c677e696426496c7a616d66666d486d7869266f677e">[email protected]</span></a>.
EPA Region 9, Anita Lee, AZ, CA, HI, NV, American Samoa,
<a href="/cdn-cgi/l/email-protection#460a23236807282f32270623362768212930"><span class="__cf_email__" data-cfemail="e0ac8585cea18e899481a0859081ce878f96">[email protected]</span></a>. Commonwealth of the Northern
Mariana Islands, Guam.
EPA Region 10, Angeles Herrera, AK, ID, OR, WA.
<a href="/cdn-cgi/l/email-protection#064e63747463746728476861636a63754663766728616970"><span class="__cf_email__" data-cfemail="68200d1a1a0d1a094629060f0d040d1b280d1809460f071e">[email protected]</span></a>.
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SUPPLEMENTARY INFORMATION:
Docket. The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2024-0078. All documents in the docket are
listed in <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Although listed, some
information is not publicly available, e.g., Confidential Business
Information (CBI) or other information the disclosure of which is
restricted by statute. Certain other material, such as copyrighted
material, is not placed on the internet and will be publicly available
as PDF versions that can only be accessed on the EPA computers in the
docket office reading room. Certain databases and physical items cannot
be downloaded from the docket but may be requested by contacting the
docket office at (202) 566-1744. With the exception of such material,
publicly available docket materials and a plain language summary of the
action are available electronically at <a href="https://www.regulations.gov">https://www.regulations.gov</a>.
Written Comments. Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2024-0078, at <a href="https://www.regulations.gov">https://www.regulations.gov</a> (the EPA's
preferred method) or the other methods identified in the ADDRESSES
section. Once submitted, comments cannot be edited or removed from the
docket. The EPA will publish any comment received to the Agency's
public docket. Do not submit to the EPA's docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> any information you consider to be CBI, Proprietary
Business Information (PBI), or other information the disclosure of
which is restricted by statute. This type of information should be
submitted as discussed below. Multimedia submissions (audio, video,
etc.) must be accompanied by a written comment. The written comment is
considered the official comment and should include discussion of all
points you wish to make. The EPA will generally not consider comments
or comment contents located outside of the primary submission (i.e., on
the web, cloud, or other file sharing system). Please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a> for additional submission
methods; the full EPA public comment policy; information about CBI,
PBI, or multimedia submissions; and general guidance on making
effective comments.
Submitting CBI. Do not submit information containing CBI to the EPA
through <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Clearly mark the part or all of
the information that you claim to be CBI. For CBI information on any
digital storage media that you mail to the EPA, note the docket ID,
mark the outside of the digital storage media as CBI, and identify
electronically within the digital storage media the specific
information that is claimed as CBI. In addition to one complete version
of the comments that includes information claimed as CBI, you must
submit a copy of the comments that does not contain the information
claimed as CBI directly to the public docket through the procedures
outlined in Written Comments section above. If you submit any digital
storage media that does not
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contain CBI, mark the outside of the digital storage media clearly that
it does not contain CBI and note the docket ID. Information not marked
as CBI will be included in the public docket and the EPA's electronic
public docket without prior notice. Information marked as CBI will not
be disclosed except in accordance with procedures set forth in 40 Code
of Federal Regulations (CFR) part 2.
Our preferred method to receive CBI is electronic transmission
using email attachments, File Transfer Protocol (FTP), or other online
file sharing services (e.g., Dropbox, OneDrive, Google Drive).
Electronic submissions must be transmitted directly to the Office of
State Air Partnerships (OSAP) CBI Office at the email address
<a href="/cdn-cgi/l/email-protection#e28d91839281808ba2879283cc858d94"><span class="__cf_email__" data-cfemail="7f100c1e0f1c1d163f1a0f1e51181009">[email protected]</span></a> and, as described above, should include clear CBI
markings and note the docket ID. If assistance is needed with
submitting large electronic files that exceed the file size limit for
email attachments, and if you do not have your own file sharing
service, please email <a href="/cdn-cgi/l/email-protection#e68995879685848fa6839687c8818990"><span class="__cf_email__" data-cfemail="e28d91839281808ba2879283cc858d94">[email protected]</span></a> to request a file transfer link.
If sending CBI information through the postal service, please send it
to the following address: U.S. Environmental Protection Agency, Attn:
OSAP Document Control Officer, Mail Drop: C404-02, 109 T.W. Alexander
Drive, P.O. Box 12055, Research Triangle Park, North Carolina 27711,
Attention Docket ID No. EPA-HQ-OAR-2024-0078. The mailed CBI material
should be double wrapped and clearly marked. Any CBI markings should
not show through the outer envelope.
Preamble acronyms and abbreviations. Throughout this preamble, the
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. We
use multiple acronyms and terms in this preamble. While this list may
not be exhaustive, to ease the reading of this preamble and for
reference purposes, the EPA defines the following terms and acronyms
here:
CAA Clean Air Act
CBI Confidential Business Information
CFR Code of Federal Regulations
DV Design Value
EPA Environmental Protection Agency
FR Federal Register
FTP File Transfer Protocol
NAAQS National Ambient Air Quality Standard or Standards
OSAP Office of State Air Partnerships
PBI Proprietary Business Information
PM Particulate Matter
SIP State Implementation Plan
TAS Treatment in a Similar Manner as a State
U.S.C. United States Code
Table of Contents
I. Overview of Action
II. Legal Authority
III. The EPA's Intended Approach to Area Designations
I. Overview
Under CAA section 107(d), the EPA is to issue area designations
upon promulgation of a new or revised NAAQS. On February 7, 2024, the
EPA promulgated revisions to the primary annual PM<INF>2.5</INF> NAAQS
to a level of 9.0 micrograms per cubic meter ([micro]g/m\3\) as
described in 40 CFR 50.20.\1\ On July 17, 2026, the Northern District
Court of California ordered the EPA to publish final designations for
all areas of the country no later than February 6, 2027.\2\ Although
EPA is appealing the order, EPA is also moving forward in the absence
of action from the judiciary, to complete the designations.
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\1\ 89 FR 16202 (Mar. 6, 2024).
\2\ All. of Nurses for Healthy Env'ts v. Zeldin, No. 26-cv-
03118-HSG (N.D. Cal. July 17, 2026).
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As a general matter, the first step in the designations process is
for the Governors of States and territories, and Tribes, if they so
choose, to submit initial area designations to the EPA. Whenever the
EPA intends to modify a Governor's initial designation, the Agency must
notify the State, territory, or Tribe no later than 120 days prior to
promulgating final designations.\3\ These notifications are informally
referred to as 120-day letters.
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\3\ The EPA notified Tribes that have obtained treatment in a
similar manner as a state (TAS) under CAA section 301(d) and 40 CFR
part 49 for purposes of CAA section 107(d), and those Tribes that
may be affected by a nonattainment designation in the relevant
State.
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This notice of availability provides notice of the EPA's intended
approach for designations for the 2024 annual PM<INF>2.5</INF> NAAQS
under CAA section 107(d)(1)(B). The EPA invites public input regarding
area designations during the 30-day comment period announced in this
notice. To receive full consideration, input from the public must be
submitted to the docket by the date provided in the DATES section of
this document. This notice and opportunity for public comment does not
affect any rights or obligations of any State, territory, or Tribe, or
of the EPA, which might otherwise exist pursuant to CAA section 107(d).
II. Legal Authority
Following promulgation of a new or revised NAAQS, CAA section
107(d) requires the EPA to designate areas of the country as
attainment, nonattainment, or unclassifiable for that NAAQS. CAA
section 107(d)(1)(A)(i)-(iii) defines: (i) nonattainment, as any area
that does not meet (or that contributes to ambient air quality in a
nearby area that does not meet) the NAAQS; (ii) attainment, as any area
(other than an area identified in clause (i)) that meets the NAAQS; and
(iii) unclassifiable, as any area that cannot be classified on the
basis of available information as meeting or not meeting the NAAQS.
Generally, the designations process involves identifying areas of the
country that either meet or do not meet the NAAQS, along with any
nearby areas that are causing or contributing to NAAQS violations. The
EPA calculates design values (DVs) at monitors to determine whether a
given area has met the 2024 annual PM<INF>2.5</INF> NAAQS, based on
procedures outlined in 40 CFR part 50, Appendix N.\4\ The 2024 annual
PM<INF>2.5</INF> NAAQS is met at an ambient air quality monitoring site
when the annual arithmetic mean, averaged over three years (i.e., the
DV) is less than or equal to 9.0 [micro]g/m\3\.
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\4\ In accordance with 40 CFR part 50 Appendix N,
PM<INF>2.5</INF> measurements from the primary monitor and suitable
collocated PM<INF>2.5</INF> Federal Reference Method (FRM) or
Federal Equivalent Method (FEM) may be used in a ``combined site
data record'' to establish a PM<INF>2.5</INF> design value to
determine whether the NAAQS is met or not met at a particular
PM<INF>2.5</INF> monitoring site. For final area designations, the
EPA intends to rely on Air Quality System (AQS) data from 2023-2025.
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In accordance with the statutory timeline prescribed under CAA
section 107(d)(1)(A), Governors of each State or territory were
required to submit a list of initial designations for all areas of
their State or territory by February 7, 2025. Though not required,
Tribal governments were encouraged to submit initial designations for
their respective areas of Indian Country.\5\ These submissions
generally relied on the 2021-2023 DVs and other information relevant to
that time period. When promulgating final designations, the EPA will
use the most recently available ambient air monitoring data and other
information. The EPA intends to rely on DVs from the 2023-2025 period
for promulgating final area designations.
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\5\ After promulgation of a new or revised NAAQS, each Governor
or Tribal leader has an opportunity to submit initial area
designations to the EPA. Consistent with the approach outlined in
the EPA's 2011 Policy for Establishing Separate Air Quality
Designations for Areas of Indian Country, in circumstances in which
the Agency either does not receive an initial area designation
letter from a Tribe, or receives a letter that does not specify
designation of a separate area, the Agency intends to designate the
relevant Tribe's Indian country as part of the surrounding multi-
jurisdictional area. See memorandum from Stephen D. Page to Regional
Air Directors, Regions 1-10, <a href="https://www.epa.gov/sites/default/files/2015-09/documents/20120117indiancountry.pdf">https://www.epa.gov/sites/default/files/2015-09/documents/20120117indiancountry.pdf</a>.
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The EPA evaluates the initial area designation submissions from
States,
[[Page 63519]]
the District of Columbia, territories, and Tribes as part of the
Agency's duty to promulgate final designations for a new or revised
NAAQS. CAA section 107(d)(1)(B)(ii) provides that, whenever the EPA
intends to modify an initial designation for a State, territory, or
Tribe, the Agency must notify the State, territory, or Tribe no later
than 120 days before the date the Administrator promulgates final
designations. CAA section 107(d)(1)(B)(ii) further requires the EPA to
provide such State with an opportunity to demonstrate why any potential
modification is inappropriate. Although not required by the CAA, the
EPA has issued letters notifying all States, the District of Columbia
territories, and certain Tribes of EPA's intended approach for
finalizing designations, including instances where the State,
territory, or Tribe declined to submit an initial area designation. The
EPA's 120-day letters requested that the States provide additional
information to the Agency within 30 days of receipt of the letters.
III. The EPA's Intended Approach to Area Designations
A. What is the EPA's intended approach for area designations?
Consistent with CAA section 107(d)(1), the EPA has conducted an
evaluation of the most recent and relevant air quality information
available. This includes evaluation of the complete and certified
PM<INF>2.5</INF> ambient air quality monitoring data, including the
2021-2023 DVs on which States, the District of Columbia, territories,
and Tribes, based their initial designation submissions. Additionally,
the EPA evaluated and utilized the most recent complete and certified
PM<INF>2.5</INF> air quality monitoring data, including the 2023-2025
DVs, and other available technical information pertinent to these
designations. Furthermore, the EPA considered the information submitted
from States, the District of Columbia, territories, and Tribes in their
initial area designations.
On or about October 2, 2026, in accordance with CAA section
107(d)(1)(B)(ii), the EPA completed its obligation to notify States of
any intended modification to initial designations no later than 120-
days prior to promulgating final designations. The EPA notified all
States, the District of Columbia, territories, and certain Tribes as to
whether the EPA intends to modify aspects of the State's initial
designations for the 2024 annual PM<INF>2.5</INF> NAAQS. With respect
to State initial designations that indicated ``attainment,'' and where
the EPA functionally agrees with the State recommendation, the Agency
intends to designate those States as ``attainment/unclassifiable.'' As
a functional matter, there is no change for those States; the statutory
and regulatory burdens of ``attainment'' and ``attainment/
unclassifiable'' are the same.
Information may be submitted to the EPA's public docket regarding
these intended designations at EPA-HQ-OAR-2024-0078, available at
<a href="http://www.regulations.gov">www.regulations.gov</a>. Pursuant to CAA section 107(d)(1)(B) and following
consideration of any additional information the EPA receives, the
Agency anticipates completing final designations consistent with CAA
requirements and in a timely manner commensurate with any applicable
court order. The EPA is available to assist States, the District of
Columbia, territories, and Tribes with any outstanding matters
concerning appropriate designations for all remaining areas.
B. Where can I find information related to these designations?
Information is provided in the individual 120-day letters
themselves and the dataset(s) included in the docket. The relevant
datasets, technical assistance documents, applicable EPA guidance
memoranda, and copies of correspondence regarding this process between
the Agency and the States, along with other parties, are available for
review at the public docket for these 2024 annual PM<INF>2.5</INF>
NAAQS designations at <a href="http://www.regulations.gov">http://www.regulations.gov</a> under Docket ID No.
EPA-HQ-OAR-2024-0078, at the EPA Docket Center listed in the FOR
FURTHER INFORMATION CONTACT section of this document, and on the
Agency's Particulate Matter Designations website at <a href="https://www.epa.gov/particle-pollution-designations">https://www.epa.gov/particle-pollution-designations</a>.
Aaron Szabo,
Assistant Administrator, Office of Air and Radiation.
[FR Doc. 2026-20468 Filed 10-5-26; 8:45 am]
BILLING CODE 6560-50-P
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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.