(Honorific title abbreviation, Random order)
- IHI Corporation
- IHI Enviro Corporation
- EBARA CORPORATION
- EBARA ENVIRONMENTAL PLANT CO., LTD.
- EBARA JITSUGYO CO., LTD.
- OKANO TRADING CO., LTD.
- KUBOTA Corporation
- KOBELCO ECO-SOLUTIONS CO., LTD.
- KOBELCO ECO-MAINTENANCE CO., LTD.
- NIPPON STEEL & SUMITOMO METAL CORPORATION
- CHUGAI RO CO., LTD.
- Kawasaki Heavy Industries, Ltd.
- JFE Engineering Corporation
- TSUKISHIMA KIKAI Co., Ltd.
- NGK INSULATORS, LTD.
- METAWATER Co., Ltd.
- Nippon Paper Industries Co., Ltd.(Jujo Paper Co., Ltd.)
- BAB-HITACHI INDUSTRIAL Co.
- Hitachi Metals, Ltd.
- Hitachi, Ltd.
- Hitachi Zosen Corporation
- Mitsubishi Heavy Industries Environmental & Chemical Engineering Co., Ltd.
- Mitsubishi Heavy Industries Ltd.
- Mitsui Zosen Environment Engineering Corporation
- KINSEI SANGYO CO., LTD.
- Local governments