| CCaptiveaire | Redding | CA | — | ◇ UNVERIFIED |
| CCaptiveaire | Englewood | OH | — | ◇ UNVERIFIED |
| C3Captiveaire 360 Youngsville Addition | Youngsville | NC | — | ◇ UNVERIFIED |
| CDCarbon Designs | Springdale | AR | — | ◇ UNVERIFIED |
| CSCardinal Sheet Metal INC | Riverside | CA | — | ◇ UNVERIFIED |
| CFCarl Fisher Co., INC. | Springfield | MA | — | ◇ UNVERIFIED |
| CRCarpenter's Roofing & Sheet Metal, INC. | West Palm Beach | FL | — | ◇ UNVERIFIED |
| CICartel Industries LLC | Irvine | CA | — | ◇ UNVERIFIED |
| CSCarver Sheet Metal Works, Inc. | Salt Lake City | UT | — | ◇ UNVERIFIED |
| CICastle Industries INC. of Ca. | Ontario | CA | — | ◇ UNVERIFIED |
| CICavotec Inet US INC. | Cypress | CA | — | ◇ UNVERIFIED |
| CSCb Strain & Son INC. | Tarrytown | NY | — | ◇ UNVERIFIED |
| CFC&c Fabrication, INC. | Carrollton | GA | — | ◇ UNVERIFIED |
| CDC & D Metal Products, INC. | Thornton | CO | — | ◇ UNVERIFIED |
| CRCedar Rock Holdings, LLC | Lenoir | NC | — | ◇ UNVERIFIED |
| CMCeh Metal Technologies Longmont Division | Longmont | CO | — | ◇ UNVERIFIED |
| CICentek INC / Centek Facility | Oklahoma City | OK | — | ◇ UNVERIFIED |
| CPCenterline Prefab LLC | Grand Rapids | MI | — | ◇ UNVERIFIED |
| CSCenter Sheet Metal, INC. | Brooklyn | NY | — | ◇ UNVERIFIED |
| CMCenterville Manufacturing LLC | Centerville | SD | — | ◇ UNVERIFIED |
| CCCentral Cal Metals | Fresno | CA | — | ◇ UNVERIFIED |
| CFCentral Florida Metals AND Central FL Metals, LLC | Orlando | FL | — | ◇ UNVERIFIED |
| CKCentral Kentucky Industrial INC | Richmond | KY | — | ◇ UNVERIFIED |
| COCentral Ohio Sheet Metal Company | Reynoldsburg | OH | — | ◇ UNVERIFIED |
| CSCentral Sheet Metal, LLC | Wichita Falls | TX | — | ◇ UNVERIFIED |
| CSCentral Sheet Metal, LLC | Seminole | OK | — | ◇ UNVERIFIED |
| CSCentral Sheet Metal Products, INC. | Skokie | IL | — | ◇ UNVERIFIED |
| CSCentral States Manufacturing, INC. | Hartford | SD | — | ◇ UNVERIFIED |
| CWCentral Wisconsin Flex | Weston | WI | — | ◇ UNVERIFIED |
| CICew INC | Bakersfield | CA | — | ◇ UNVERIFIED |
| CMCfc Manufacturing Co., INC. | Carbondale | PA | — | ◇ UNVERIFIED |
| CHCfm Heating & Air Conditioning INC | Ogden | UT | — | ◇ UNVERIFIED |
| CMChadwick Manufacturing, LTD. | Chadwick | IL | — | ◇ UNVERIFIED |
| CTChamco Tools | Kansas City | MO | — | ◇ UNVERIFIED |
| CMChampagne Metals | South Charleston | WV | — | ◇ UNVERIFIED |
 Chancey Metals Ramonda Blvd Facility | Jacksonville | FL | — | ◇ UNVERIFIED |
 Chandler Industries INC Stremel Division | Minneapolis | MN | — | ◇ UNVERIFIED |
| CWCheckpoint Welding - Fabrication INC | Minneapolis | MN | — | ◇ UNVERIFIED |
| CWChenoa Welding & Fabrication, INC. | Chenoa | IL | — | ◇ UNVERIFIED |
| CBChicago Blow Pipe Company | Marquette | MI | — | ◇ UNVERIFIED |
| CMChi Manufacturing, INC. | Englewood | CO | — | ◇ UNVERIFIED |
| CWChristian W K Metal Works | Bristol | TN | — | ◇ UNVERIFIED |
| CRChristopher Ray Stilson | Port Allegany | PA | — | ◇ UNVERIFIED |
| CICirclemaster, INC | Santee | CA | — | ◇ UNVERIFIED |
| CSCitory Solutions, LLC | Saint Cloud | FL | — | ◇ UNVERIFIED |
| CMC&j Metal Products | Paramount | CA | — | ◇ UNVERIFIED |
| CICkkm INC | Corona | CA | — | ◇ UNVERIFIED |
| CCClabber Creek Closet Co. | Mchenry | IL | — | ◇ UNVERIFIED |
| CIClad Industries LLC | Macedon | NY | — | ◇ UNVERIFIED |
| CIClamp It Coping LLC | Springville | UT | — | ◇ UNVERIFIED |
