Conformity Adequacy Review: Region 8

State Implementation Plans (SIP) Submissions that EPA has Found Adequate or Inadequate
Region 8: Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming

For more information about adequacy review, return to the main adequacy page.

Contact: Gregory Lohrke at 303-312-6396 Lohrke.gregory@epa.gov
U.S. EPA Region 8, 1595 Wynkoop St., Denver, Colorado 80202.

Colorado
Area
Pollutant
SIP Submission
Finding (date budgets apply)
Additional Information/ Comments
Aspen PM10 maintenance plan Adequate (6/11/2012)
Adequate Letter (6/11/2012) (pdf) (1.3 MB, August 11, 2011)
FR Notice		 Budgets found adequate through the adequacy review process.
Adequate (9/4/2002)
Adequate Letter (9/4/2002) (pdf) (89.06 KB)
FR Notice		 Budgets found adequate through the adequacy review process.
Canon City PM10 maintenance plan Adequate (8/17/2011)
Adequate Letter (8/17/2011) (pdf) (1.16 MB, May 4, 2011)
FR Notice		 Budgets found adequate through the adequacy review process.
Adequate (7/31/2000)
FR Notice		 Budgets found adequate through SIP approval process.
Colorado Springs carbon monoxide limited maintenance plan Adequate (8/17/2011)
Adequate Letter (8/17/2011) (pdf) (1.27 MB, March 3, 2011)
FR Notice		 Budgets found adequate through the adequacy review process.
maintenance plan 1998-2009 budgets Inadequate (4/29/1999) Determination made under old process
maintenance plan 2010 budget and beyond Adequate (4/29/1999) Determination made under old process
Denver 2008 8-hour ozone reasonable further progress Adequate (6/8/2023)
Letter (pdf) (219.08 KB, May 3, 2023)
FR Notice		 Budgets found adequate through the adequacy review process.
attainment plan Adequate (4/2/2018)
Adequate Letter (4/2/2018) (pdf) (116.99 KB, January 30, 2018)
FR Notice		 Budgets found adequate through the adequacy review process
1997 8-hour ozone attainment plan Adequate (3/19/2010)
Adequate Letter (3/19/2010) (pdf) (1.28 MB, January 21, 2010)
FR Notice		 Budgets found adequate through the adequacy review process.
pm10 maintenance plan Adequate (6/28/2007)
Adequate Letter (6/28/2007) (pdf) (161.75 KB, May 3, 2007)
FR Notice		 Budgets found adequate through the adequacy review process.
Adequate (10/29/2001)
Adequate Letter (10/29/2001) (pdf) (35 KB)
FR Notice		 Budgets found adequate through the adequacy review process.
carbon monoxide maintenance plan Adequate (6/28/2007)
Adequate Letter (6/28/2007) (pdf) (154.83 KB, May 3, 2007) >
FR Notice		 Budgets found adequate through the adequacy review process.
Adequate (8/18/2000)
Adequate Letter (8/18/2000) (pdf) (42.98 KB, July 12, 2000)
FR Notice		 Budgets found adequate through the adequacy review process.
Fort Collins carbon monoxide limited maintenance plan Adequate (6/11/2012)
Adequate Letter (6/11/2012) (pdf) (970.14 KB, August 9, 2011)
FR Notice		 Budgets found adequate through the adequacy review process.
maintenance plan Adequate (1/15/2003)
Adequate Letter (1/15/2003) (pdf) (25.49 KB, January 15, 2003)
FR Notice		 Budgets found adequate through the adequacy review process.
Greeley carbon monoxide limited maintenance plan Adequate (8/17/2011)
Adequate Letter (8/17/2011) (pdf) (1.3 MB, March 4, 2011)
FR Notice		 Budgets found adequate through the adequacy review process.
maintenance plan Adequate (1/20/2004)
Adequate Letter (1/20/2004) (pdf) (31.46 KB, October 29, 2003)
FR Notice		 Budgets found adequate through the adequacy review process.
Lamar PM10 second maintenance plan adequate 10/20/2014
79 FR 59767 printed 10/03/2014		 Budgets found adequate through the adequacy review process
maintenance plan Adequate (11/12/2002)
Adequate Letter (11/12/2002) (pdf) (115.65 KB, September 25, 2002)
FR Notice		 Budgets found adequate through the adequacy review process.
Longmont carbon monoxide maintenance plan Adequate (6/28/2007)
Adequate Letter (6/28/2007) (pdf) (151.68 KB, May 3, 2007)
FR Notice		 Budgets found adequate through the adequacy review process.
Inadequate (5/14/1999) Determination made under old process
Pagosa Springs PM10 maintenance plan Adequate (8/17/2011)
Adequate Letter (8/17/2011) (pdf) (1.47 MB, March 17, 2011)
FR Notice		 Budgets found adequate through the adequacy review process.
Adequate (8/18/2000)
Adequate Letter (8/18/2000) (pdf) (42.98 KB, July 12, 2000)
FR Notice		 Budgets found adequate through the adequacy review process.
Steamboat Springs PM10 second maintenance plan adequate 10/20/2014
79 FR 59767 printed 10/03/2014		 Budgets found adequate through the adequacy review process.
maintenance plan Adequate (11/12/2002)
Adequate Letter (11/12/2002) (pdf) (115.65 KB, September 25, 2002)
FR Notice		 Budgets found adequate through the adequacy review process.
Telluride PM10 maintenance plan Adequate (8/17/2011)
Adequate Letter (8/17/2011) (pdf) (1.49 MB, March 21, 2011)
FR Notice		 Budgets found adequate through the adequacy review process.
Adequate (8/18/2000)
Adequate Letter (8/18/2000) (pdf) (42.98 KB, July 12, 2000)
FR Notice		 Budgets found adequate through the adequacy review process.
Montana
Area
Pollutant
SIP Submission
Finding (date budgets apply)
Additional Information/ Comments
Missoula PM 10 maintenance plan Adequate (10/12/2018) Letter (Missoula PM10 Limited Maintenance Plan) (pdf) (903.64 KB, July 23, 2018)
FR Notice (printed 9/27/2018) 83 FR 48715		 Budgets found adequate through the adequacy review process.
carbon monoxide maintenance plan Adequate (11/13/2017 )82 FR 43180 printed 9/14/2017) Budgets found adequate through the SIP approval process.
Adequate (6/16/2006)
Adequate Letter (6/16/2006) (pdf) (324.72 KB, May 4, 2006)
FR Notice (PDF)(2 pp, 141 K, published June 1, 2006,  About PDF)		 Budgets found adequate through the adequacy review process.
Utah
Area
Pollutant
SIP Submission
Finding (date budgets apply)
Additional Information/ Comments
Ogden carbon monoxide maintenance plan Adequate (6/10/2005)
Adequate Letter (6/10/2005) (pdf) (302.09 KB, May 2, 2005)
FR Notice (pdf) (144 KB, published May 26, 2005)		 Budgets found adequate through the adequacy review process.
carbon monoxide maintenance plan Adequate (4/29/1999) Determination made under old process
Provo (Utah County) carbon monoxide attainment demonstration Adequate (8/4/2004)
Adequate Letter (8/4/2004) (pdf) (86.7 KB, June 30, 2004)
FR Notice (PDF)(1 pp, 138 K, published July 20, 2004, About PDF)		 Budgets found adequate through the adequacy review process.
PM10 attainment demonstration (2010 & 2020 budgets) Adequate (10/16/2002)
Adequate Letter (10/16/2002) (pdf) (100.19 KB, September 5, 2002)
FR Notice		 Budgets found adequate through the adequacy review process.
carbon monoxide attainment demonstration Inadequate (5/14/1999) Determination made under old process
Salt Lake City Area carbon monoxide maintenance plan Adequate (6/15/2005)
Adequate Letter (6/15/2005) (pdf) (283.41 KB, May 2, 2005)
FR Notice (PDF)(1 pp, 139 K, published May 31, 2005, About PDF)		 Budgets found adequate through the adequacy review process.

Utah portion of Logan UT-ID Area

PM2.5

attainment demonstration

Adequate (9/28/2015)
FR Notice(published September 11, 2015)

Budgets found adequate through the adequacy review process

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Last updated on May 29, 2025