Attachment to Part B Comments of Earthjustice et al., EPA-HQ-OLEM-2019-0173

Assessment Monitoring Outcomes (2019)

EPA’s Final Ash Rule, 40 C.F.R. § 257.94(e)(3), requires the owners or operators of existing Coal Combustion Residuals (CCR) units to prepare a notification stating that an assessment monitoring program has been established if it is determined that a statistically significant increase over background levels for one or more of the constituents listed in appendix III of the CCR Rule has occurred, without an alleged alternate source demonstration.

This table identifies the CCR surface impoundments known to be in assessment monitoring and required to identify any constituent(s) in appendix IV detected at statistically significant levels (SSL) above groundwater protection standards and post notice of the assessment monitoring outcome per 40 C.F.R. § 257.95. The table includes the surface impoundments that were required to post notice of appendix IV exceedance(s), as applicable, or elected to do so as of the time of this assessment monitoring outcomes review (summer 2019). To the best of our knowledge, neither EPA nor any other entity has attempted to assemble this information and make it public. Note that this document is not confirming that the industry notifications or assessments were compliant with the CCR Rule or that additional units may not belong on this list.

Assessment Monitoring Outcome # of Surface Impoundments Appendix IV Exceedance(s) 214 Appendix IV Exceedance(s), alleged Alternate Source Demonstration 16 No Appendix IV Exceedance Reported 64 Total 294

Name of Plant Appendix IV Operator CCR Unit or Site Exceedance(s) Healy Power Plant GVEA AK Unit 1 Ash Pond Yes Healy Power Plant GVEA AK Unit 1 Emergency Overflow Pond Yes Healy Power Plant GVEA AK Unit 1 Recirculating Pond Yes Charles R. Lowman Power Power South Energy Cooperative AL Flue-Gas Desulfurization Waste (FGD) Pond Yes Plant Charles R. Lowman Power Power South Energy Cooperative AL Unit #1 Ash Pond Yes Plant Charles R. Lowman Power Power South Energy Cooperative AL Unit #2/3 Ash Pond Yes Plant Colbert Fossil Plant Valley Authority AL Ash Disposal Area 4 CCR Unit Yes E.C. Gaston Steam Plant Alabama Power AL Plant Gaston Gypsum Pond Yes, alleged ASD E.C. Gaston Steam Plant Alabama Power AL Plant Gaston Ash Pond Yes James H. Miller, Jr., Electric Alabama Power AL Plant Miller Ash Pond Yes Generating Plant James M. Barry Electric Alabama Power AL Gypsum Storage Pond No Generating Plant James M. Barry Electric Alabama Power AL Ash Pond Yes Generating Plant Plant Greene County Alabama Power AL Ash Pond Yes William C. Gorgas Electric Alabama Power AL Ash Pond Yes Generating Plant William C. Gorgas Electric Alabama Power AL Gypsum Pond Yes Generating Plant Arizona Public Service Electric Cholla Power Plant AZ SEDI (Sedimentation Pond, Cooling Pond Dam) No Company Arizona Public Service Electric Cholla Power Plant AZ Bottom Ash Pond Yes Company Arizona Public Service Electric Cholla Power Plant AZ Fly Ash Pond Yes Company Cherokee Station Xcel Energy CO Center Ash Pond No Cherokee Station Xcel Energy CO East Ash Pond No Cherokee Station Xcel Energy CO West Ash Pond No Rawhide Energy Station Platte River Power Authority CO Bottom Ash Transfer Impoundment 1 Yes Rawhide Energy Station Platte River Power Authority CO Bottom Ash Transfer Impoundment 2 Yes Valmont Station Xcel Energy CO CCR Impoundment 3A Yes Valmont Station Xcel Energy CO CCR Impoundment 3B Yes Deerhaven Generating Gainesville Regional Utilities FL Surface Impoundment System No Station Plant Crist Gulf Power FL Gypsum Storage Area Yes Plant Smith Gulf Power FL CCR Ash Pond Yes Power Company GA Ash Pond 1 Yes Plant Crisp Crisp County Power Commission GA Ash Pond No Plant Hammond Company GA Ash Pond 1 Yes Plant Hammond Georgia Power Company GA Ash Pond 2 Yes Plant McIntosh Georgia Power Company GA Ash Pond 1 Yes Georgia Power Company GA Ash Pond 1 Yes, alleged ASD Plant Wansley Georgia Power Company GA Ash Pond Yes, alleged ASD Plant Yates Georgia Power Company GA Ash Pond 2 No Plant Yates Georgia Power Company GA Ash Pond 3 Yes Plant Yates Georgia Power Company GA Ash Pond B Yes Plant Yates Georgia Power Company GA Ash Pond B' Yes Burlington Generating Interstate Power and Light IA Ash Seal Pond Yes Station Company Burlington Generating Interstate Power and Light IA Economizer Ash Pond Yes Station Company Burlington Generating Interstate Power and Light IA Main Ash Pond Yes Station Company Burlington Generating Interstate Power and Light IA Upper Ash Pond Yes Station Company Interstate Power and Light Lansing Generating Station IA Upper Ash Pond Yes Company Louisa Generating Station MidAmerican Energy Co. IA Impoundment No Neal North Energy Center MidAmerican Energy Co. IA Impoundment 3B No Interstate Power and Light Ottumwa Generating Station IA OGS Ash Pond Yes Company Prairie Creek Generating Interstate Power and Light IA PCS Discharge Pond Yes Station Company Prairie Creek Generating Interstate Power and Light IA PCS Pond 1 Yes Station Company Prairie Creek Generating Interstate Power and Light IA PCS Pond 2 Yes Station Company Prairie Creek Generating Interstate Power and Light IA PCS Pond 3 Yes Station Company Prairie Creek Generating Interstate Power and Light IA PCS Pond 4 Yes Station Company Prairie Creek Generating Interstate Power and Light IA PCS Pond 5 Yes Station Company Prairie Creek Generating Interstate Power and Light IA PCS Pond 6 Yes Station Company Prairie Creek Generating Interstate Power and Light IA PCS Pond 7 Yes Station Company Walter Scott Jr. Energy MidAmerican Energy Co. IA South Surface Impoundment No Center Baldwin Energy Complex Luminant (formerly Dynegy Inc.) IL Baldwin Bottom Ash Pond Yes Baldwin Energy Complex Luminant (formerly Dynegy Inc.) IL East Fly Ash Pond Yes Baldwin Energy Complex Luminant (formerly Dynegy Inc.) IL Old East Fly Ash Pond Yes Baldwin Energy Complex Luminant (formerly Dynegy Inc.) IL West Fly Ash Pond Yes Coffeen Luminant (formerly Dynegy Inc.) IL Coffeen Ash Pond No. 2 Yes Coffeen Power Station Luminant (formerly Dynegy Inc.) IL Coffeen Ash Pond No. 1 Yes Coffeen Power Station Luminant (formerly Dynegy Inc.) IL Coffeen GMF Recycle Pond None reported Dallman Power Generating City Water, Light and Power IL Dallman Ash Pond Yes Station Dallman Power Generating City Water, Light and Power IL Lakeside Ash Pond Yes Station

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Edwards Power Station Luminant (formerly Dynegy Inc.) IL Edwards Ash Pond None reported Havana Power Station Luminant (formerly Dynegy Inc.) IL Havana East Ash Pond (Cells 1, 2, 3, and 4) None reported Hennepin Power Station Luminant (formerly Dynegy Inc.) IL Hennepin Old West Polishing Pond Yes Henepin Old West Ash Pond (Pond No. 1 and Hennepin Power Station Luminant (formerly Dynegy Inc.) IL Yes Pond No. 3) Hennepin Power Station Luminant (formerly Dynegy Inc.) IL Hennepin Ash Pond No. 2 Yes Hennepin Power Station Luminant (formerly Dynegy Inc.) IL Hennepin East Ash Pond None reported Joppa Power Station Luminant (formerly Dynegy Inc.) IL Joppa East Ash Pond None reported Kincaid Power Station Luminant (formerly Dynegy Inc.) IL Ash Pond None reported Marion Power Plant SIPC IL Emery Holding Pond Yes Powerton Generating Station NRG IL Ash By-pass Basin Yes Powerton Generating Station NRG IL Ash Surge Basin Yes Wood River Power Station Luminant (formerly Dynegy Inc.) IL Wood River West Ash Pond 2W None reported Wood River Power Station Luminant (formerly Dynegy Inc.) IL Wood River West Ash Pond 2E None reported Wood River Power Station Luminant (formerly Dynegy Inc.) IL Wood River West Ash Pond 1 None reported Wood River Power Station Luminant (formerly Dynegy Inc.) IL Wood River Primary East Ash Pond Yes A.B. Brown Generating SIGECO, dba Vectren Power Supply IN Ash Pond Yes Station Northern Indiana Public Service Bailly Generating Station IN Bailly Primary 1 Yes Company Northern Indiana Public Service Bailly Generating Station IN Bailly Primary 2 Yes Company Northern Indiana Public Service Bailly Generating Station IN Bailly Secondary 1 Yes Company Northern Indiana Public Service Bailly Generating Station IN Bailly Boiler Slag Pond No Company Cayuga Generating Station Duke Energy IN Secondary Ash Settling Pond Yes Cayuga Generating Station Duke Energy IN Lined Ash Disposal Area Yes Cayuga Generating Station Duke Energy IN Primary Ash Settling Pond Yes Clifty Creek Station Indiana-Kentucky Electric Corp. IN Landfill Runoff Collection Pond Yes Eagle Valley Generating Indianapolis Power & Light IN Pond A Yes Station Company Eagle Valley Generating Indianapolis Power & Light IN Pond B Yes Station Company Eagle Valley Generating Indianapolis Power & Light IN Pond C Yes Station Company F.B. Culley Generating Station SIGECO, dba Vectren Power Supply IN East Ash Pond Yes Gallagher Generating Station Duke Energy IN Ash Pond A Yes Gallagher Generating Station Duke Energy IN Primary Pond Yes Gibson Generating Station Duke Energy IN North Ash Pond Yes Gibson Generating Station Duke Energy IN North Settling Basin Yes Harding Street Generating Indianapolis Power & Light IN Pond 1 Yes Station Company Harding Street Generating Indianapolis Power & Light IN Pond 2A Yes Station Company Harding Street Generating Indianapolis Power & Light IN Pond 2B Yes Station Company Harding Street Generating Indianapolis Power & Light IN Pond 3 Yes Station Company Michigan City Generating Northern Indiana Public Service IN Michigan City Boiler Slag Pond None reported Station Company Petersburg Generating Indianapolis Power & Light IN Pond A' Yes Station Company Petersburg Generating Indianapolis Power & Light IN Pond C Yes Station Company Petersburg Generating Indianapolis Power & Light IN Pond A Yes Station Company R.M. Schahfer Generating Northern Indiana Public Service IN Waste Disposal Area Yes, alleged ASD Station Company R.M. Schahfer Generating Northern Indiana Public Service IN Drying Area Yes Station Company R.M. Schahfer Generating Northern Indiana Public Service IN Material Storage Runoff Basin Yes Station Company

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R.M. Schahfer Generating Northern Indiana Public Service IN Metal Cleaning Waste Basin Yes Station Company Rockport Plant American Electric Power IN Bottom Ash Pond None reported Wabash River Generating Duke Energy IN South Ash Pond Yes, alleged ASD Station Wabash River Generating Duke Energy IN Ash Pond A Yes Station Wabash River Generating Duke Energy IN Ash Pond B Yes Station Wabash River Generating Duke Energy IN Secondary Settling Pond Yes Station Nearman Creek Power Kansas City Board of Public Utilities KS Bottom Ash Pond Yes, alleged ASD Station Tecumseh Energy Center Westar Energy KS Bottom Ash Settling Pond Yes American Electric Power, Kentucky Big Sandy Plant KY Bottom Ash Pond None reported Power Co. American Electric Power, Kentucky Big Sandy Plant KY Fly Ash Pond Yes, alleged ASD Power Co. E.W. Brown Generating Kentucky Utilities Company KY Auxiliary Pond Yes Station East Bend Electric Plant Duke Energy KY Ash Basin No Elmer Smith Station Owensboro Municipal Utilities KY Coal Ash Ponds Yes Ghent Generating Station Kentucky Utilities Company KY Gypsum Stack Yes Ghent Generating Station Kentucky Utilities Company KY Reclaim Pond/Gypsum Stack Surge Pond Yes Ghent Generating Station Kentucky Utilities Company KY Ash Treatment Basin 1 Yes Ghent Generating Station Kentucky Utilities Company KY Ash Treatment Basin 2 Yes Ghent Generating Station Kentucky Utilities Company KY Secondary Pond Yes H.L. Spurlock Power Station East Kentucky Power Cooperative KY CCR Ash Pond No Mill Creek Generating Station Louisville Gas & Electric Company KY Ash Treatment Basin Yes Paradise Fossil Plant Tennessee Valley Authority KY Gypsum Disposal Area No Paradise Fossil Plant Tennessee Valley Authority KY Gypsum Disposal Area Stilling Pond 1 No Paradise Fossil Plant Tennessee Valley Authority KY Gypsum Disposal Area Stilling Pond 2 No Paradise Fossil Plant Tennessee Valley Authority KY Peabody Ash Pond Yes Paradise Fossil Plant Tennessee Valley Authority KY Slag Ponds Area Yes Paradise Fossil Plant Tennessee Valley Authority KY Slag Stilling Pond 2C Yes Sebree Generating Station Big Rivers Electric Corporation KY Reid/HMPL Station CCR Surface Impoundment Yes Tennessee Valley Authority KY SHF Ash Pond 2 (Main Ash Pond/Stilling Pond) Yes Trimble County Generating Louisville Gas & Electric Company KY Bottom Ash Pond Yes Station Trimble County Generating Louisville Gas & Electric Company KY Gypsum Storage Pond Yes Station Big Cajun II Power Plant CLECO LA Bottom Ash Pond None reported Big Cajun II Power Plant CLECO LA Fly Ash Pond None reported Brayton Point Power Station Brayton Point LLC MA Basin B None reported Brayton Point Power Station Brayton Point LLC MA Basin A None reported Brayton Point Power Station Brayton Point LLC MA Basin C None reported BC Cobb Power Plant Consumers Energy Co. MI Bottom Ash Pond Yes BC Cobb Power Plant Consumers Energy Co. MI Ponds 0-8 Yes DE Karn Power Plant Consumers Energy Co. MI Bottom Ash Pond Yes JB Sims Power Generation Consumers Energy Co. MI Inactive Unit 1 & 2 Ponds Yes Plant JB Sims Power Generation Consumers Energy Co. MI Unit 3 Ash Ponds East (A) and West (B) Yes Plant JC Weadock Power Plant Consumers Energy Co. MI Bottom Ash Pond Yes JH Campbell Power Plant Consumers Energy Co. MI Unit 3 North & 3 South None reported JH Campbell Power Plant Consumers Energy Co. MI Units 1-2 North and 1-2 South Yes JH Campbell Power Plant Consumers Energy Co. MI Pond A Yes River Rouge Power Plant DTE Electric Co. MI Bottom Ash Basin Yes Boswell Energy Center Minnesota Power MN Bottom Ash Surface Impoundment Yes, alleged ASD Boswell Energy Center Minnesota Power MN Unit 3 Impoundment Yes, alleged ASD Boswell Energy Center Minnesota Power MN Unit 4 Impoundment Yes, alleged ASD Sherburne County Xcel Energy MN Bottom Ash Pond None reported Generating Plant

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Sherburne County Xcel Energy MN Solids Pond No. 3 None reported Generating Plant Labadie Energy Center Ameren MO LCPA Yes Meramec Energy Center Ameren MO CCR Unit MCPA Yes Meramec Energy Center Ameren MO CCR Unit MCPB Yes Meramec Energy Center Ameren MO CCR Unit MCPC Yes Meramec Energy Center Ameren MO CCR Unit MCPD Yes New Madrid Power Plant Associated Electric Coop. MO Pond 004 None reported New Madrid Power Plant Associated Electric Coop. MO Pond 003 Yes Rush Island Energy Center Ameren MO RCPA Surface Impoundment Yes Sioux Energy Center Ameren MO SCPA (Bottom Ash Pond) Yes Plant Victor Daniel Mississippi Power MS Ash Pond B Yes, alleged ASD Colstrip Steam Electric Talen Energy MT 3&4 EHP, J Cell Yes Station Colstrip Steam Electric Talen Energy MT 3&4 EHP, A Cell Yes Station Colstrip Steam Electric Talen Energy MT 1&2 STEP, E Cell Yes Station Colstrip Steam Electric Talen Energy MT 1&2 STEP, Old Clearwell Yes Station Colstrip Steam Electric Talen Energy MT 3&4 EHP, B Cell Yes Station Colstrip Steam Electric Talen Energy MT 3&4 EHP, C Cell Yes Station Colstrip Steam Electric Talen Energy MT 3&4 EHP, D/E Cell Yes Station Colstrip Steam Electric Talen Energy MT 3&4 EHP, G Cell Yes Station Colstrip Steam Electric Talen Energy MT 3&4 EHP, J-1 Cell** Yes Station Colstrip Steam Electric Talen Energy MT Units 1&2 B Fly Ash Pond Yes Station Colstrip Steam Electric Talen Energy MT Units 3&4 Bottom Ash Pond Yes Station Colstrip Steam Electric Talen Energy MT Units 1&2 Bottom Ash Pond Yes Station Lewis & Clark Station Montana-Dakota Utilities Co. MT Scrubber Pond (East) Yes Lewis & Clark Station Montana-Dakota Utilities Co. MT Scrubber Pond (West) Yes Allen Steam Station Duke Energy NC Active Ash Basin Yes Allen Steam Station Duke Energy NC Retired Ash Basin Yes Asheville Steam Electric Plant Duke Energy NC 1964 Ash Basin Yes Asheville Steam Electric Plant Duke Energy NC 1982 Ash Basin Yes Belews Creek Steam Station Duke Energy NC Active Ash Basin Yes Buck Steam Station Duke Energy NC Additional Primary Pond (Ash Basin 1) Yes Buck Steam Station Duke Energy NC Primary Pond (Ash Basin 2) Yes Buck Steam Station Duke Energy NC Secondary Pond (Ash Basin 3) Yes Cliffside Steam Station Duke Energy NC Inactive Units 1 - 4 Basin Yes Cliffside Steam Station Duke Energy NC Active Ash Basin Yes Cliffside Steam Station Duke Energy NC Inactive Unit 5 Basin Yes Dan River Steam Station Duke Energy NC Primary Ash Basin Yes Dan River Steam Station Duke Energy NC Secondary Ash Basin Yes H.F. Lee Energy Complex Duke Energy NC Active Ash Basin Yes L.V. Sutton Energy Complex Duke Energy NC 1971 Ash Basin Yes L.V. Sutton Energy Complex Duke Energy NC 1984 Ash Basin Yes Marshall Steam Station Duke Energy NC Active Ash Basin Yes Mayo Steam Electric Plant Duke Energy NC Ash Basin No Mayo Steam Electric Plant Duke Energy NC FGD Forward Flush Pond No Mayo Steam Electric Plant Duke Energy NC FGD Settling Pond No Roxboro Steam Electric Plant Duke Energy NC East Ash Pond Yes Roxboro Steam Electric Plant Duke Energy NC East FGD Settling Pond Yes Roxboro Steam Electric Plant Duke Energy NC FGD Forward Flush Pond Yes Roxboro Steam Electric Plant Duke Energy NC West Ash Basin Yes Roxboro Steam Electric Plant Duke Energy NC West FGD Settling Pond Yes

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W.H. Weatherspoon Power Duke Energy NC 1979 Ash Basin Yes Plant Public Power Generation Whelan Energy Center NE WEC Temporary Ash Disposal Area None reported Agency/Hastings Utilities Four Corners Power Plant Arizona Public Service Co. NM Upper Retention Sump Yes Four Corners Power Plant Arizona Public Service Co. NM Lined Ash Impoundment Yes Four Corners Power Plant Arizona Public Service Co. NM Lined Decant Water Pond Yes Cayuga Power Plant Somerset Operating Company, LLC NY Sludge Stabilization Basin None reported Huntley Generating Station NRG NY South Settling Pond Yes Cardinal Plant Buckeye Power Co. & AEP OH Fly Ash Reservoir II Yes Cardinal Plant Buckeye Power Co. & AEP OH Bottom Ash Pond None reported Conesville Plant American Electric Power OH Ash Pond Yes JM Stuart Station AES Ohio Generation OH Pond 10 Yes JM Stuart Station AES Ohio Generation OH Pond 5 Yes JM Stuart Station AES Ohio Generation OH Pond 7 Yes Killen Station AES Ohio Generation OH Ash Pond Yes Kyger Creek Station Ohio Valley Electric Corp. OH Boiler Slag Pond Yes Miami Fort Power Station Luminant (formerly Dynegy Inc.) OH Miami Fort Basin A Yes Miami Fort Power Station Luminant (formerly Dynegy Inc.) OH Miami Fort Basin B Yes W.H. Sammis Power Station FirstEnergy OH North Pond Yes W.H. Sammis Power Station FirstEnergy OH South Pond Yes Zimmer Power Station Luminant (formerly Dynegy Inc.) OH Coal Pile Runoff Pond None reported Zimmer Power Station Luminant (formerly Dynegy Inc.) OH D Basin None reported Zimmer Power Station Luminant (formerly Dynegy Inc.) OH Gypsum Recycle Pond None reported Northeastern 3&4 Power American Electric Power OK Bottom Ash Pond Yes Station Bruce Mansfield Plant FirstEnergy PA Little Blue Run Disposal Facility Yes Brunner Island Steam Electric Talen Energy PA Ash Basin No. 6 Yes Station Cheswick Generating Station GenOn PA Bottom Ash Emergency Pond No Cheswick Generating Station GenOn PA Bottom Ash Recycle Pond No Bottom Ash Pond A (#0386201) [retrofit in Keystone Generating Station GenOn PA No process] Bottom Ash Pond B (#0386201) [retrofit in Keystone Generating Station GenOn PA No process] Bottom Ash Pond C (#0386201) [retrofit cert Keystone Generating Station GenOn PA No 12/17] Montour Steam Electric Talen Energy PA Ash Basin No. 1 Yes, alleged ASD Station New Castle Generating GenOn PA North Ash Pond Yes Station Cross Generating Station Santee Cooper SC Bottom Ash Pond Yes H.B. Robinson Steam Electric Duke Energy SC Ash Basin Yes Plant W.S. Lee Steam Station Duke Energy SC Primary Ash Basin Yes W.S. Lee Steam Station Duke Energy SC Secondary Ash Basin Yes Wateree Generating Station South Carolina Electric & Gas SC Ash Pond Yes Winyah Generating Station Santee Cooper SC South Ash Pond None reported Winyah Generating Station Santee Cooper SC Ash Pond A Yes Winyah Generating Station Santee Cooper SC Ash Pond B Yes Winyah Generating Station Santee Cooper SC Slurry Pond 3&4 Yes, alleged ASD Tennessee Valley Authority TN East Ash Disposal Area CCR Unit Yes Tennessee Valley Authority TN Bottom Ash Pond Yes Cumberland Fossil Plant Tennessee Valley Authority TN Stilling Pond (Incl. Retention Pond) Yes Tennessee Valley Authority TN Ash Pond A Yes Gallatin Fossil Plant Tennessee Valley Authority TN Ash Pond E Yes Gallatin Fossil Plant Tennessee Valley Authority TN Bottom Ash Pond Yes Gallatin Fossil Plant Tennessee Valley Authority TN Middle Pond A Yes Johnsonville Fossil Plant Tennessee Valley Authority TN Active Ash Pond 2 CCR Unit Yes Big Brown Steam Electric Luminant Generation Co., LLC TX N. Bottom Ash Pond None reported Station Big Brown Steam Electric Luminant Generation Co., LLC TX S. Bottom Ash Pond None reported Station

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Coleto Creek Power Station Luminant (formerly Dynegy Inc.) TX Coleto Creek Primary Ash Pond None reported Gibbons Creek Steam Electric Texas Municipal Power Agency TX Ash Ponds Yes Generating Station Gibbons Creek Steam Electric Texas Municipal Power Agency TX Scrubber Sludge Pond Yes Generating Station H.W. Pirkey Power Plant American Electric Power TX East Bottom Ash Pond Yes, alleged ASD H.W. Pirkey Power Plant American Electric Power TX West Bottom Ash Pond Yes, alleged ASD J. Robert Welsh Power Plant American Electric Power TX Primary Bottom Ash Pond Yes, alleged ASD Martin Lake Steam Electric Luminant Generation Co., LLC TX East Ash Pond Yes Station Martin Lake Steam Electric Luminant Generation Co., LLC TX New Scrubber Pond Yes Station Martin Lake Steam Electric Luminant Generation Co., LLC TX West Ash Pond Yes Station Oak Grove Steam Electric Luminant Generation Co., LLC TX FGD-A Pond Yes Station Oak Grove Steam Electric Luminant Generation Co., LLC TX FGD-B Pond Yes Station Oak Grove Steam Electric Luminant Generation Co., LLC TX FGD-C Pond Yes Station San Miguel Electric Cooperative, Ash Water Transport Ponds (N. Ash Pond A & San Miguel Plant TX Yes Inc. S. Ash Pond B) San Miguel Electric Cooperative, San Miguel Plant TX Equalization Pond Yes Inc. Intermountain Generating Intermountain Power Service Corp. UT Bottom Ash Basin Yes Facility Intermountain Generating Intermountain Power Service Corp. UT Waste Water Basin Yes Facility Bremo Power Station Dominion Energy VA North Ash Pond Yes Chesterfield Power Station Dominion Energy VA Lower Ash Pond Yes Chesterfield Power Station Dominion Energy VA Upper Ash Pond Yes Clover Power Station Dominion Energy VA Sludge Sedimentation Basins No Possum Point Power Station Dominion Energy VA Pond D Yes John E Amos Plant American Electric Power WV Bottom Ash Pond CCR Management Unit None reported Mitchell Plant American Electric Power WV Bottom Ash Pond None reported Mountaineer Plant American Electric Power WV Bottom Ash Pond CCR Management Unit Yes Allegheny Energy Supply Co. WV McElroy's Run Disposal Impoundment Yes Dave Johnston Power Plant PacifiCorp Energy WY Ash Pond Unit (4A & 4B) Yes Jim Bridger Power Plant PacifiCorp Energy WY FGD Pond 1 Yes Jim Bridger Power Plant PacifiCorp Energy WY FGD Pond 2 No Laramie River Station Basin Electric Power Cooperative WY Ash Pond 1 Yes Laramie River Station Basin Electric Power Cooperative WY Ash Pond 2 No Laramie River Station Basin Electric Power Cooperative WY Ash Pond 3 No Laramie River Station Basin Electric Power Cooperative WY East Emergency Holding Pond No Laramie River Station Basin Electric Power Cooperative WY West Emergency Holding Pond No Naughton Power Plant PacifiCorp Energy WY FGD Pond 1 Yes Naughton Power Plant PacifiCorp Energy WY FGD Pond 2 Yes Naughton Power Plant PacifiCorp Energy WY South Ash Pond Yes 294

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