- Alta Science and Engineering
- Anderson Environmental Contracting, LLC
- BB&A Environmental
- Cascade Drilling/Technical Services
- Clean Harbors
- CleanWay Environmental Partners, Inc.
- Clear Creek Systems, Inc.
- Clear Water Services, LLC
- Cemtek KVB-Enertec
- CIF Composites Inc.
- EDR
- ERIS - Environmental Risk Information Services
- GeoSearch
- Gunderson
- Heritage Environmental Services, LLC
- Holocene Drilling
- Holt Services, Inc.
- Ingenium Group
- JRW Bioremediation
- Kennedy/Jenks Consultants
- Landau Associates
- Montrose Air Quality Services
- MP Environmental Services, Inc.
- Olympic Environmental Equipment, LLC
- Pace National
- PBS Engineering & Environmental
- PNE dba CCS
- River City Environmental
- SoilFreeze, Inc.
- SPECTRA Laboratories
- Stericycle Environmental Solutions
- Stoel Rives
- StormwateRx LLC
- TRC Environmental
- TSI Inc.
- United Rentals Fluid Solutions
- Wapato Valley Mitigation & Conservation Bank
- WasteXpress Environmental
- WaterTectonics
- Willamette Cultural Resources Associates, Ltd.
- Wood Environment & Infrastructure Solutions, Inc.
- Yellow Jacket Drilling Services LLC