| CGCarlton Global | Dunn | CA | — | ◇ UNVERIFIED |
| CPCarolina Perlite Company, INC. | Gold Hill | NC | — | ◇ UNVERIFIED |
| CPCarolina Perlite Company, INC. | Gold Hill | NC | — | ◇ UNVERIFIED |
| CSCarolina Stalite CO Aquadale Properties | Norwood | NC | — | ◇ UNVERIFIED |
| CCCarus Chemical CO | Ottawa | IL | — | ◇ UNVERIFIED |
| CNCass Nv, LLC | Mccarran | NV | — | ◇ UNVERIFIED |
| CCCastle Concrete CO Queens Canyon Quarry | Colorado Springs | CO | — | ◇ UNVERIFIED |
| CCCelite Corporation | Quincy | WA | — | ◇ UNVERIFIED |
| CMC-e Minerals Plants 1,2 and 6 | Andersonville | GA | — | ◇ UNVERIFIED |
| CKCentral Ky Process | Lexington | KY | — | ◇ UNVERIFIED |
| CSCentral States Refining CO INC | Versailles | MO | — | ◇ UNVERIFIED |
| CFCentre Foundry & Machine CO. Wheeling | Wheeling | WV | — | ◇ UNVERIFIED |
| CACentury Aluminum of Kentucky General Partnership | Hawesville | KY | — | ◇ UNVERIFIED |
| COCharles O. Hiler & Son in | Walkerton | IN | — | ◇ UNVERIFIED |
| CMCharleston Mill Service | Huger | SC | — | ◇ UNVERIFIED |
| CMCharleston Mill Service | Huger | SC | — | ◇ UNVERIFIED |
| CSCharleston Steel and Metal Company | North Charleston | SC | — | ◇ UNVERIFIED |
| CPChemical Pollution Control of Florida LLC - Unit #2 | Deerfield Beach | FL | — | ◇ UNVERIFIED |
| CIChovanak INC | Helena | MT | — | ◇ UNVERIFIED |
| CLChuck Lorentz | Montrose | CO | — | ◇ UNVERIFIED |
| CPCimbar Performance Minerals | Mount Vernon | IN | — | ◇ UNVERIFIED |
| CCinao | Batavia | OH | — | ◇ UNVERIFIED |
| CMCity Materials Services, INC. | Hermitage | PA | — | ◇ UNVERIFIED |
| COCity of Quapaw Potw | Quapaw | OK | — | ◇ UNVERIFIED |
| CCClariant Corporation - Quincy Operation | Quincy | FL | — | ◇ UNVERIFIED |
| CPClimax Performance Material | Golden | CO | — | ◇ UNVERIFIED |
| CEClodine Expanded Shale & Clay Products | Richmond | TX | — | ◇ UNVERIFIED |
| CNC & N CORP. | Galena | KS | — | ◇ UNVERIFIED |
| CWCoast Wide Ready Mix | Tillamook | OR | — | ◇ UNVERIFIED |
| CSCoatesville Scrap Iron & Metal Fac | Coatesville | PA | — | ◇ UNVERIFIED |
| CMColeman Manufacturing | Everett | MA | — | ◇ UNVERIFIED |
| CMColombo Mine | Sierra City | CA | — | ◇ UNVERIFIED |
| CMColumbia Metal Products CO | Kansas City | MO | — | ◇ UNVERIFIED |
| CIColumbine Iron & Metal | Erie | CO | — | ◇ UNVERIFIED |
| CEComax Enterprises, INC. | Riverdale | IL | — | ◇ UNVERIFIED |
| CMCommercial Metals CO | Joplin | MO | — | ◇ UNVERIFIED |
| CMCommercial Metals Company Recycling | Jacksonville | FL | — | ◇ UNVERIFIED |
| CMCommerial Metals Company | Waco | TX | — | ◇ UNVERIFIED |
| CRCommodity Resource & Envrnmtl | Mojave | CA | — | ◇ UNVERIFIED |
| CACommonwealth Aluminum Carson Rolling Mill | Long Beach | CA | — | ◇ UNVERIFIED |
 Constellium Rolled Products - Ravenswood | Ravenswood | WV | — | ◇ UNVERIFIED |
| CMContact Mining Company | Philipsburg | MT | — | ◇ UNVERIFIED |
| CAContinental Aluminum | New Hudson | MI | — | ◇ UNVERIFIED |
| CCContract Crushing Const - Patton Site | Belle Vernon | PA | — | ◇ UNVERIFIED |
| CICoorstek, Inc.- South Table Mountain | Golden | CO | — | ◇ UNVERIFIED |
| CLCornerstone - Lakeview Process Site | Lakeview | OR | — | ◇ UNVERIFIED |
| CCCorpus Christi Alloys & Manufacturing INC. | Corpus Christi | TX | — | ◇ UNVERIFIED |
| CWCostco Wholesale - Columbus | Columbus | OH | — | ◇ UNVERIFIED |
| CICovia Isp, INC. | Fort Smith | AR | — | ◇ UNVERIFIED |
| CMCroft Metals INC | Newton | MS | — | ◇ UNVERIFIED |
