| Sept. 1990: | 1,1,1-trichloroethane, trichloroethylene, and dichloromethane reduction activity began |
| March 1993: | OKI Electric environmental protection activity plan decided on |
| March 1993: | Specific freon totally abolished |
| Sept. 1993: | 1,1,1-trichloroethane totally abolished |
| May 1995: | Preevaluation system for environmental influence of product design and packaging established |
| Dec. 1995: | ISO 14001 authorization acquisition plan announced to media |
| Aug. 1996: | Basic environmental policies and new environmental protection activity plan decided on |
| Feb. 1997: | Miyazaki Oki Electric Co.,Ltd acquired ISO 14001 authorization |
| March 1997: | Trichloroethlene and dichloromethane totally abolished |
| July 1997: | Hachioji district acquired ISO 14001 authorization |
| March 1998: | Major production bases of OKI acquired ISO 14001 authorization |
| Dec. 1998: | Major production bases of OKI Group acquired ISO 14001 authorization |
| Feb. 1999: | Miyagi Oki Electric Co.,Ltd received Energy Agency Director General Award as top rated resource energy management factory |
| March 1999: | Company standard for "Green procurement guidelines" established |