If a Risk Management Plan (RMP) facility is sold to a new owner, does the new owner have to develop a whole new RMP? Or can they use the existing RMP?

No, a facility does not complete a new RMP as the facility keeps the original EPA Facility ID number that was assigned to the source. If there are not any significant changes to plant operations, the facility would just need to submit a correction of ownership information to the RMP on record with EPA by the date ownership changes or responsibility for operation of the facility is transferred. The facility should also make any required corrections per 40 CFR 68.195 if needed. Additionally, if significant changes have been made to plant operations such that one of the update triggers in 40 CFR 68.190(b) occurs, the facility is required to complete an update of all sections of the RMP and resubmit it to EPA.