Safe: Any SCP object classed as Safe is usually little more than a curiosity to the research teams, but is still anomalous enough to warrant containment in some form or another. Any SCP object classified as Safe can be interacted with by any member of staff, regardless of security clearance. This is also the only class of SCP object that anyone of O5-x clearance is permitted access to, though even then only under controlled circumstances.
Keep in mind that Safe class objects are not completely harmless: an automobile, or an AK-47, for instance, would be considered Safe, although it is capable of killing human beings. However, its functions are understood, and reliable safety measures can be taken to avoid harm.
Euclid: Euclid classification is generally applied to objects whose properties are not currently understood. Unlike Safe class objects, there are no reliable containment procedures on Euclid class objects: this may be because the object either does not obey known laws of nature and physics, or because its response to stimuli constantly changes. Objects classified as Euclid may be declined to Safe if a greater understanding of their properties is achieved.
Euclid class objects are not necessarily inherently dangerous, but they are unpredictable: for this reason, greater care should be taken around them. A wild animal, for instance may be considered Euclid, as it may have unpredictable responses to stimuli.
Keter: The strictest object class, Keter-class objects can only be handled by Class D personnel (see Security Clearance Levels) except in special circumstances. Keter objects are naturally inimical to life and pose great difficulties in keeping them controlled, hence the use of Class D personnel in their maintenance. Keter objects fall into one of two categories: those that are of immense strategic value once controlled, or those that have been deemed impossible to destroy due to the nature of the artifact. In either case, the artifact is to be kept until its use has been ascertained and replicated in a more controlled environment, or until a method of ensuring the objects' permanent destruction is determined.
Keter class objects are always inherently dangerous, despite the best containment procedures possible: the threat level may range from global armageddon to simply killing everything around it. A hand grenade with the pin removed may be considered Keter: a single mistake will cause casualties.
Neutralized: Any object that has since been destroyed, or in some way has no odd, extra-dimensional, or adverse effects. Objects classified under this class should have a note stating what class it was while it was an active SCP.
Decommissioned: Reserved for objects that are not only destroyed, but disavowed by the Foundation.
