Every effort is made to avoid abandoning class VII items due to contamination. Class IX Contaminated class IX items are normally issued only in emergencies. In such cases, items for critical weapon systems may be issued. Before issue, the items are marked with the standard NBC markers. Repair parts, especially sensitive electronic parts, must be checked for damage before issue.
Decontamination is time consuming, and it causes corrosion and damage to some types of equipment.
Providing overhead cover for equipment and supplies will significantly reduce liquid contamination of such materiel. Petroleum products trap chemical contamination. They collect in bolt threads, hydraulic fluids, and closed assemblies. Hence, a vehicle maybe safe to drive without MOPP 4, but not be safe to repair. Also, since oil, grease, and dirt degrade the effectiveness of chemical overgarments, mechanics must keep as clean as possible.