D: Class D personnel are designated staff used to handle the Keter-level objects. WARNING: CLASS D PERSONNEL ARE NOT ALLOWED TO INTERACT WITH CLASS D PERSONNEL ASSIGNED TO A DIFFERENT OBJECT OR SCP PERSONNEL. Class D personnel are recruited from prison inmates. Condemned persons are preferred; in times of duress, Protocol 12 can be authorized, allowing recruitment of innocents or persons incarcerated for lesser crimes. All Class D personnel must be terminated at the first of the month, and a new staff must be ready to replace them. After placement in quarters, staff must only contact Class D personnel through intercom system. All personnel involved with Class D will be given a minimum of one (1) polygraph tests at 1800 on a daily basis. Failure to comply will result in termination. Failure to pass test will result in termination. In event of any abnormalities, termination of entire Class D personnel is advised, as well as any SCP personnel that has had basic interaction.
E: Temporarily affixed to the start of a security clearance (e.g. E1), this is used when a new SCP object has been discovered but is still in an unsecured or uncontrolled state. E-clearance personnel are tasked with bringing the SCP into effect and maintaining it. Once the SCP are in place and the object is secure, the E is removed and the personnel are given the appropriate number on the end of their clearance.
O5-x: Overseer-level clearance is given only to the directors of the SCP Project. The x indicates their number, ranging from 1 to 12 (e.g. O5-7). O5 personnel are permitted to access any and all data related to the SCP objects. However, due to the sensitive nature of their position, O5 personnel are not permitted to have any direct contact with a SCP object, nor may they enter any site housing a SCP object under any circumstances.