The Indian Health Service (IHS) administers the Catastrophic Health Emergency Fund, The purpose of CHEF is to meet the extraordinary medical costs associated with the treatment of victims of disasters or catastrophic illnesses who are within the responsibility of the Service. This proposed rule: Proposes definitions governing the CHEF; establishes that a Service Unit shall not be eligible for reimbursement for the cost of treatment until the episode of care's cost has reached a certain threshold; establishes a procedure for reimbursement for certain services exceeding a threshold cost; establishes a procedure for payment for certain cases; and, establishes a procedure to ensure payment will not be made from CHEF if other sources of payment (Federal, state, local, private) are available.