Protective custody (PC) is a type of imprisonment (or care) to protect a person from harm, either from outside sources or other prisoners. Many prison administrators believe the level of violence, or the underlying threat of violence within prisons, is a chief factor causing the need for PC units. Prisoners have the opportunity to request protective custody if they get the impression that the environment they are living in is harmful to their well being. Their request may be granted if the officials rule that the prisoner is truly at risk. Protective custody might simply involve putting the person in a secure prison (if the threat is from the outside), but usually protective custody involves some degree of solitary confinement. For people who are threatened because of their association with a certain group or gang, moving them to another section of the prison may be sufficient.