| LCLunday-Thagard Company, d/b/a World Oil Refining, a California Corporation | South Gate | CA | 20–99 | ◐ LIKELY ACTIVE |
Luxfer Magtech Saxonburg Plt | Saxonburg | PA | — | ◐ LIKELY ACTIVE |
| LMLuxfer MEL Technologies - Saxonburg | Saxonburg | PA | 20–99 | ◐ LIKELY ACTIVE |
| MIMagretech Incorporated | Bellevue | OH | 20–99 | ◐ LIKELY ACTIVE |
| MIMagsphere, INC. | Pasadena | CA | — | ▲ REPORTED CLOSED |
| MPMarathon Petroleum Company LP | Findlay | OH | — | ◐ LIKELY ACTIVE |
| MLMarkwest Langley Processing Plant | Langley | KY | — | ◐ LIKELY ACTIVE |
| MRMarshallton Research Laboratories, INC. | Tobaccoville | NC | — | ◐ LIKELY ACTIVE |
| MRMartinez Refining Company LLC (previously Shell Oil Products Us, Martinez Ref.) | Martinez | CA | — | ◐ LIKELY ACTIVE |
| MHMarysville Hydrocarbons | Marysville | MI | — | ◐ LIKELY ACTIVE |
| MPMastercraft Pattern C/o Jonah Bishop | Pittsburg | KS | — | ◐ LIKELY ACTIVE |
| MAMaterion Advanced Chemicals INC. | Milwaukee | WI | — | ◐ LIKELY ACTIVE |
| MCMaterion CORP | Albuquerque | NM | — | ◐ LIKELY ACTIVE |
| MIMecs INC | Martinez | CA | 20–99 | ◐ LIKELY ACTIVE |
| MIMedford International Holdings | Medford | OR | 1–19 | ◐ LIKELY ACTIVE |
| MGMetalico-college Grove, INC. | College Grove | TN | — | ◐ LIKELY ACTIVE |
Metal Products | Suwanee | GA | — | ◐ LIKELY ACTIVE |
| MSMexichem Specialty Resins, INC. | Henry | IL | 100–499 | ◐ LIKELY ACTIVE |
| MSMichigan State University - Bioeconomy Institute | Holland | MI | — | ◐ LIKELY ACTIVE |
| MCMidland Corteva Agrisciences | Midland | MI | 500+ | ◐ LIKELY ACTIVE |
| MRMid-States Recycling & Refining | Des Plaines | IL | 20–99 | ◐ LIKELY ACTIVE |
| MWMiller Waste Mills INC Dba Rtp Company | Henderson | KY | — | ◐ LIKELY ACTIVE |
| MPMilne Point Unit | Prudhoe Bay | AK | — | ◐ LIKELY ACTIVE |
| MLMinasolve LLC | Memphis | TN | — | ◐ LIKELY ACTIVE |
| MCMitsubishi Chemical America, Performance Polymers | Greer | SC | 20–99 | ◐ LIKELY ACTIVE |
| MCMitsubishi Chemical Group | Stockton | CA | 20–99 | ◐ LIKELY ACTIVE |
| MAMonroe Alfrebro, LLC | Monroe | OH | 20–99 | ◐ LIKELY ACTIVE |
| MRMontana Renewables LLC | Great Falls | MT | — | ◐ LIKELY ACTIVE |
| MFMosaic Fertilizer LLC Bonnie Facility | Bartow | FL | — | ◐ LIKELY ACTIVE |
| MFMosaic Fertilizer, LLC - Hardee North Pasture Mine | Wauchula | FL | — | ◐ LIKELY ACTIVE |
| MFMosaic Fertilizer Llc, Plant City Facility | Plant City | FL | — | ◐ LIKELY ACTIVE |
| MPMosaic Phosphates Company - Nichols Plant | Mulberry | FL | — | ◐ LIKELY ACTIVE |
| MTMosaic Tampa Marine Terminal | Tampa | FL | — | ◐ LIKELY ACTIVE |
| MEMotiva Enterprises LLC | Port Arthur | TX | 500+ | ◐ LIKELY ACTIVE |
| MIM&u International LLC | Branchburg | NJ | — | ◐ LIKELY ACTIVE |
| MPMulberry Phosphogypsum Stack System Closure | Bartow | FL | — | ◐ LIKELY ACTIVE |
| MAMundell & Associates, INC. | Indianapolis | IN | — | ◐ LIKELY ACTIVE |
| MIMuscatine, IA | Muscatine | IA | 100–499 | ◐ LIKELY ACTIVE |
| MLMytee LLC | Poway | CA | 20–99 | ◐ LIKELY ACTIVE |
| NLNaprotec LLC | Chattanooga | TN | — | ◐ LIKELY ACTIVE |
| NMNational Molding LLC | Miami Lakes | FL | — | ◐ LIKELY ACTIVE |
| NSNational Starch and Chemical Company | Enoree | SC | — | ◐ LIKELY ACTIVE |
| NONecessary Oil & Trucking CO | Bristol | TN | — | ◐ LIKELY ACTIVE |
| NNewchem | New Cumberland | WV | — | ◐ LIKELY ACTIVE |
| NENew England Biolabs, INC. | Ipswich | MA | — | ◐ LIKELY ACTIVE |
| NPNewport Plastics - Ncic Property | Lyndon | VT | — | ◐ LIKELY ACTIVE |
| NRNew Rise Renewables Reno, LLC | Mccarran | NV | 20–99 | ◐ LIKELY ACTIVE |
| NHNexolve Holding Company - Quality Circle Facility | Huntsville | AL | — | ◐ LIKELY ACTIVE |
| NNNexpera - New Orleans Central | Chalmette | LA | 1–19 | ◐ LIKELY ACTIVE |
| NANorac Additives, LLC | Helena | AR | 20–99 | ◐ LIKELY ACTIVE |