| DMD&s Mag and Peen INC Dba Tri-process Company | Paramount | CA | — | ◇ UNVERIFIED |
| DCDuffy CO | Palatine | IL | — | ◇ UNVERIFIED |
| EMEastern Metal Treating | Enfield | CT | — | ◇ UNVERIFIED |
| EHEast-lind Heat Treat, INC | Madison Heights | MI | — | ◇ UNVERIFIED |
| EIEastwind Investments LLC | Troutdale | OR | — | ◇ UNVERIFIED |
| EMEklund Metal Treating INC | Loves Park | IL | — | ◇ UNVERIFIED |
| ECElk Cnty Heat Treaters/st Marys | Saint Marys | PA | — | ◇ UNVERIFIED |
| EIEllipsis, INC. | Kent | OH | — | ◇ UNVERIFIED |
| EMExcel Metal Finishing INC | Minneapolis | MN | — | ◇ UNVERIFIED |
| EExtrudehone | Paramount | CA | — | ◇ UNVERIFIED |
| FFFairchild Fastener Group Rosan | Santa Ana | CA | — | ◇ UNVERIFIED |
| FLFbf Limited Dba Queen City Steel Treating CO | Cincinnati | OH | — | ◇ UNVERIFIED |
| FDFederal-mogul Driveline Products | Forest View | IL | — | ◇ UNVERIFIED |
| FLFlight Labs LLC | Phoenix | AZ | — | ◇ UNVERIFIED |
| FLFpm LLC | Itasca | IL | — | ◇ UNVERIFIED |
| GIGallmar Industries, LLC | Oshkosh | WI | — | ◇ UNVERIFIED |
 Gerdau Macsteel, INC. | Canton | OH | — | ◇ UNVERIFIED |
| GMGerdau Mt Hope Facility | Lansing | MI | — | ◇ UNVERIFIED |
| GSGerdau Special Steel North America | Pleasant Prairie | WI | — | ◇ UNVERIFIED |
| GIGlenbrook II, LLC | Milwaukee | WI | — | ◇ UNVERIFIED |
| GPGretener Prototype Engineering | Paso Robles | CA | — | ◇ UNVERIFIED |
| HIH-a Industries-div of A.m. Castle & CO | Hammond | IN | — | ◇ UNVERIFIED |
| HEHalethorpe Extrusions INC | Baltimore | MD | — | ◇ UNVERIFIED |
| HTHalstead Thermal Processing | Lakewood | OH | — | ◇ UNVERIFIED |
| HPHarris Products Group | Carthage | TN | — | ◇ UNVERIFIED |
| HTHeat Treating Services CO. | Pontiac | MI | — | ◇ UNVERIFIED |
| HTHeat Treating Services CORP of America - Plant 1 | Pontiac | MI | — | ◇ UNVERIFIED |
| HHH & H Commercial Heat Treating Inc | Muncie | IN | — | ◇ UNVERIFIED |
| HSHigh Speed Steel Treating CO | Montclair | CA | — | ◇ UNVERIFIED |
| HTHi Tech Heat Treating INC | Gardena | CA | — | ◇ UNVERIFIED |
| HIHitecmetal, INC. (1318007731) | Cleveland | OH | — | ◇ UNVERIFIED |
| HTHi Tecmetal, INC. Bmt (1318007817) | Cleveland | OH | — | ◇ UNVERIFIED |
| HLHi-temp, LLC | Northlake | IL | — | ◇ UNVERIFIED |
| HTH&l Tooth-'precision Heat Trea | Montebello | CA | — | ◇ UNVERIFIED |
| HSH&m South INC | Jacksonville | FL | — | ◇ UNVERIFIED |
| HMH & M West, INC. | Glendale | AZ | — | ◇ UNVERIFIED |
| HHHouston Heat Treating Division of Bodycote Lindberg | Houston | TX | — | ◇ UNVERIFIED |
 Hydro Honing Laboratories | East Hartford | CT | — | ◇ UNVERIFIED |
| IAImg Altair, LLC Subsidiary of Ichor Systems | Fremont | CA | — | ◇ UNVERIFIED |
| IDImt Duncan LLC | Duncan | SC | — | ◇ UNVERIFIED |
| IHIndustrial Heat Treating INC | Quincy | MA | — | ◇ UNVERIFIED |
| INInland Nw Metallurgical Servic | Spokane | WA | — | ◇ UNVERIFIED |
| INInland Nw Metallurgical Svs INC | Spokane | WA | — | ◇ UNVERIFIED |
 International Metallurgical Services INC Dba Scarrott Metallurgical Company | Los Angeles | CA | — | ◇ UNVERIFIED |
| IIIpsen INC | Roselle | NJ | — | ◇ UNVERIFIED |
| IHIronbound Heat Treating CO | Roselle | NJ | — | ◇ UNVERIFIED |
 ISO Finishing LLC | Ramseur | NC | — | ◇ UNVERIFIED |
| JHJames Heritage Ltd | Berthoud | CO | — | ◇ UNVERIFIED |
| JHJasco Heat Treating INC | Fairport | NY | — | ◇ UNVERIFIED |
| JCJ C Renfroe & Son INC | Jacksonville | FL | — | ◇ UNVERIFIED |
