| MCMesquite Concrete Cuero | Cuero | TX | 1–19 | ◐ LIKELY ACTIVE |
| MMMetromont Materials Corporation - Monroe Plant | Monroe | NC | — | ◐ LIKELY ACTIVE |
| MRMetro Ready Mix Concrete INC. | Nashville | TN | — | ◐ LIKELY ACTIVE |
| MRMetro Ready Mix & Supply Castor Ave Fac | Philadelphia | PA | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply | Henderson | KY | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply - Eddyville Plant | Eddyville | KY | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply INC - Morganfield | Morganfield | KY | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply – Owensboro Plant | Owensboro | KY | — | ◐ LIKELY ACTIVE |
| MCMeuth Construction Supply - Sebree Plant | Sebree | KY | — | ◐ LIKELY ACTIVE |
| MMMeyer Material | Mchenry | IL | — | ◐ LIKELY ACTIVE |
Meyer Utility Structures LLC | Fort Pierce | FL | — | ◐ LIKELY ACTIVE |
| MAMid America Ready Mix - Lyons Plant | Lyons | KS | — | ◐ LIKELY ACTIVE |
| MAMid Atlantic Terminals Shutdown | Chesapeake | VA | — | ◐ LIKELY ACTIVE |
| MCMiddlesboro Concrete Plant | Middlesboro | KY | — | ◐ LIKELY ACTIVE |
| MCMid-illinois Concrete INC | Sullivan | IL | — | ◐ LIKELY ACTIVE |
| MMidland | Midland | TX | 20–99 | ◐ LIKELY ACTIVE |
| MCMidland Concrete Products Clear Lake | Clear Lake | IA | 20–99 | ◐ LIKELY ACTIVE |
| MTMidland Tank Farm Crude Oil Storage Facility | Midland | TX | — | ◐ LIKELY ACTIVE |
| MCMid-missouri Concrete | Montgomery City | MO | — | ◐ LIKELY ACTIVE |
| MSMid South Concrete, INC. | Pulaski | TN | — | ◐ LIKELY ACTIVE |
| MSMid - South Concrete, INC. - Leoma | Leoma | TN | — | ◐ LIKELY ACTIVE |
| MSMid State Concrete Products LLC | Santa Maria | CA | 20–99 | ◐ LIKELY ACTIVE |
| MRMid-state Ready Mix | Columbia | KY | — | ◐ LIKELY ACTIVE |
| MCMid-States Concrete Industries | South Beloit | IL | 100–499 | ◐ LIKELY ACTIVE |
| MRMidtown Redi Mix | Westville | IL | — | ◐ LIKELY ACTIVE |
| MMMid-way Materials, INC. | Camden | TN | — | ◐ LIKELY ACTIVE |
| MBMidwest Block and Brick | Springfield | MO | — | ◐ LIKELY ACTIVE |
| MCMidwest Concrete Materials INC | Salina | KS | — | ◐ LIKELY ACTIVE |
| MMMilpitas Materials Company | Milpitas | CA | 20–99 | ◐ LIKELY ACTIVE |
| MMMini Mix INC | Clinton Twp | MI | 20–99 | ◐ LIKELY ACTIVE |
| MCMitchell Concrete Specialties, LLC | Alabaster | AL | — | ◐ LIKELY ACTIVE |
Mmc Materials Gulf Coast - Milton Plant | Milton | FL | — | ◐ LIKELY ACTIVE |
Mmc Materials Gulf Coast - Panama City Plant | Panama City | FL | — | ◐ LIKELY ACTIVE |
Mmc Materials Gulf Coast - Tyndall Plant | Tyndall Afb | FL | — | ◐ LIKELY ACTIVE |
Mmc Materials, INC. | Luverne | AL | — | ◐ LIKELY ACTIVE |
| MMMmc Materials Inc, Aberdeen Facility | Aberdeen | MS | — | ◐ LIKELY ACTIVE |
Mmc Materials Inc, Byhalia Plnt | Byhalia | MS | — | ◐ LIKELY ACTIVE |
| MMMmc Materials Inc, Columbia | Columbia | MS | — | ◐ LIKELY ACTIVE |
| MMMmc Materials Inc, Columbus 45 | Columbus | MS | — | ◐ LIKELY ACTIVE |
| MMMmc Materials Inc, Mccomb | Mccomb | MS | — | ◐ LIKELY ACTIVE |
| MMMmc Materials Inc, Natchez Plant | Natchez | MS | — | ◐ LIKELY ACTIVE |
| MMMmc Materials, Inc., North Natchez Plant | Natchez | MS | — | ◐ LIKELY ACTIVE |
| MCMoon Concrete Services, INC. | Huntsville | AL | — | ◐ LIKELY ACTIVE |
| MVMoreno Valley Plant 2 | Moreno Valley | CA | 20–99 | ◐ LIKELY ACTIVE |
| MCMorgan Concrete Company - Athens Plant | Athens | GA | 20–99 | ◐ LIKELY ACTIVE |
| MCMoritz Concrete | Effingham | IL | 20–99 | ◐ LIKELY ACTIVE |
| MTMorrison Tank & Vault, INC. | Morrison | TN | — | ◐ LIKELY ACTIVE |
| MCMountain City Plant 506 | Mountain City | TN | — | ◐ LIKELY ACTIVE |
| MEMPC Enterprises Inc | Mount Pleasant | IA | 100–499 | ◐ LIKELY ACTIVE |
| MVMt Vernon Plant | Rockcastle | KY | — | ◐ LIKELY ACTIVE |