| LRLaurel Refinery | Laurel | MT | 100–499 | ◐ LIKELY ACTIVE |
| LPLiner Products | Paoli | IN | 20–99 | ◐ LIKELY ACTIVE |
| LOLion Oil Company | El Dorado | AR | 100–499 | ◐ LIKELY ACTIVE |
| LGLouisiana Green Fuels LLC - Louisiana Green Fuels | Columbia | LA | — | ◐ LIKELY ACTIVE |
| LCLubrizol CORP | Wickliffe | OH | — | ◐ LIKELY ACTIVE |
| LOLuebbering Oil CO | Hartsburg | MO | — | ◐ LIKELY ACTIVE |
| LCLunday-Thagard Company, d/b/a World Oil Refining, a California Corporation | South Gate | CA | 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 |
| MIMedford International Holdings | Medford | OR | 1–19 | ◐ 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 |
| 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 |
| MEMotiva Enterprises LLC | Port Arthur | TX | 500+ | ◐ LIKELY ACTIVE |
| MIM&u International LLC | Branchburg | NJ | — | ◐ LIKELY ACTIVE |
| MIMuscatine, IA | Muscatine | IA | 100–499 | ◐ LIKELY ACTIVE |
| MLMytee LLC | Poway | CA | 20–99 | ◐ LIKELY ACTIVE |
| NTNalco Texarkana Plant | Texarkana | TX | — | ◐ 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 |
| 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 |
| NANorac Additives, LLC | Helena | AR | 20–99 | ◐ LIKELY ACTIVE |
| NANorth American Composites Company | Nashville | TN | — | ◐ LIKELY ACTIVE |
| NNNorthwest Natural Gas Portland Lng Plant | Portland | OR | — | ◐ LIKELY ACTIVE |
| NANovakinetics Aerosystems, INC. | Flagstaff | AZ | 20–99 | ◐ LIKELY ACTIVE |
| NPNuconic Packaging | Vernon | CA | 20–99 | ◐ LIKELY ACTIVE |
| NBNutrition & Biosciences USA 1, LLC (p1466) | Midland | MI | 100–499 | ◐ LIKELY ACTIVE |
| OPOakwood Products Inc. | Estill | SC | 20–99 | ◐ LIKELY ACTIVE |
| OCOccidental Chemical CORP | Pottstown | PA | — | ◐ LIKELY ACTIVE |
| OCOccidental Chemical Oxychem- Portland Plant | Gregory | TX | — | ◐ LIKELY ACTIVE |
| OEOctal Extrusions Corporation | West Chester | OH | 20–99 | ◐ LIKELY ACTIVE |
| OTOdessa Terminal | Odessa | TX | — | ◐ LIKELY ACTIVE |
| OFOligo Factory INC | Holliston | MA | — | ◐ LIKELY ACTIVE |