| 1 | OFK | OFEK | | IL | AVCODES |
| 2 | OFKX | Witco Chemical Corp. | added 1/1969; 4/1970-1/1975 | | NAKINA |
| 3 | OFKX | Witco Chemical Co., Inc. | added 1/1967; eliminated 1/1969 | | NAKINA |
| 4 | OFKX | Koch Tank Line, Inc. | 7/1937-10/1966; eliminated 1/1967 | | NAKINA |
| 5 | OFKX | Otto Koch | 7/1930 | | NAKINA |
| 6 | OFKX | Koch Tank Line | 7/1932-7/1935 | | NAKINA |
| 7 | OFKX | Koch Tank Line, Inc. | 4/38-10/66; eliminated 1/67 | | NRHS |
| 8 | OFKX | Witco Chemical Co., Inc. | added 1/67; eliminated 1/69 | | NRHS |
| 9 | OFKX | Witco Chemical Corp. | added 1/69; 4/70-1/75 | | NRHS |
| 10 | OFKX | WITCO CHEMICAL [KOCH TANK LINE; OTTO KOCH] | | | PWRC |
| 11 | OFKX | KOCH TANK LINE | | | SCAC3 |
