| WPWyo-Ben Pet | Billings | MT | Chemical Manufacturing325998 | 20-99 | ◐ LIKELY ACTIVE |
| EPEvolution Pyrotechnics Manufacturing, INC. | Columbus | MT | Chemical Manufacturing325998 | 20-99 | ◇ UNVERIFIED |
| ASAdvanced Silicon Materials Facility | Butte | MT | Chemical Manufacturing325188 | — | ◇ UNVERIFIED |
| BPBrenntag Pacific, INC. | Laurel | MT | Chemical Manufacturing325199 | — | ◇ UNVERIFIED |
| DLDermaxon, LLC | Missoula | MT | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| EPEvolution Pyrotechnics Manufacturing, INC. | Acton | MT | Chemical Manufacturing325998 | — | ◇ UNVERIFIED |
| HCHammen Corporation | Missoula | MT | Chemical Manufacturing325180 | — | ◇ UNVERIFIED |
| IGIndustrial Gas Distributors | Billings | MT | Chemical Manufacturing325120 | — | ◇ UNVERIFIED |
| ILIntellimet LLC | Missoula | MT | Chemical Manufacturing325211 | — | ◇ UNVERIFIED |
 Mesa Laboratories, INC. | Bozeman | MT | Chemical Manufacturing325414 | — | ◇ UNVERIFIED |
| MCMiles City Seat Base | Miles City | MT | Chemical Manufacturing325998 | — | ◇ UNVERIFIED |
| MMModern Medicinal | Columbia Falls | MT | Chemical Manufacturing325411 | — | ◇ UNVERIFIED |
| MEMontana Ethanol Project | Great Falls | MT | Chemical Manufacturing325193 | — | ◇ UNVERIFIED |
| PWPet Wellness Inc | Rexford | MT | Chemical Manufacturing325411 | — | ◇ UNVERIFIED |
| PIPolymeric Interconnect | Butte | MT | Chemical Manufacturing325211 | — | ◇ UNVERIFIED |
| QIQuake Industries, INC. | Manhattan | MT | Chemical Manufacturing325211 | — | ◇ UNVERIFIED |
| RMRocky Mountain Ethanol | Hardin | MT | Chemical Manufacturing325193 | — | ◇ UNVERIFIED |
| WSWater Science Technologies LLC - Miles City | Miles City | MT | Chemical Manufacturing325998 | — | ◇ UNVERIFIED |
