No matter which backup procedure is used, multiple backup copies should be created. One copy can be stored on-site, for use in the event of minor incidents like failure of a hard drive. In the event of a major disaster, such as a fire or flood, any backup copies stored on-site will likely be destroyed or inaccessible. Therefore, a second backup copy needs to be stored off-site. These backup files can be transported to the remote storage site either physically (e.g., by courier) or electronically. In either case, the same security controls need to be applied to backup files as are used to protect the original copy of the information. This means that backup copies of sensitive data should be encrypted both in storage and during electronic transmission. Access to backup files also needs to be carefully controlled and monitored.