When not in use and in the direct possession of an Authorized User, all controlled substance inventory must be properly secured. Before the DEA issues a Registration, they will review and approve the location in which controlled substances will be stored. Once approved, this storage arrangement may never be changed unless permission is granted from the DEA. Detailed information regarding drug storage requirements can be found in Title 21 CFR Part 1301 Section 1301.72. Minimum standards for security are based upon the drug's schedule:
- Schedule I and II: approved safe or lockable steel cabinet
- Schedules III-V: top drawer of a locked file cabinet or a locked desk drawer
- Regardless of Schedule, there can be no external markings that indicate the presence of stored controlled substances.