| C-52 | Cleaning Prior to Heat Treat Carbon & Low Alloy Steels | Chemical Processing |
| Supercedes: None | Superceded By: None |
| Number | Name | State | Country |
| 90049129 | Bodycote Thermal Processing - Huntington Park | CA | United States |
| 90049444 | Certified Steel Treating Corp | CA | United States |