All certificated state hospital employees hired to provide educational services to individuals of mandated school age after September 29, 1980, shall possess an appropriate California credential in special education. Current certificated state hospital employees who do not possess appropriate California credentials in special education shall be given a period of not more than five years from September 29, 1980, to obtain such appropriate credentials. Certificated state hospital employees who do not possess appropriate California credentials in special education at the end of the five-year period shall be reassigned to provide educational services to individuals residing in state hospitals who are not eligible for services under the Individuals with Disabilities Education Act (20 U.S.C. Sec. 1400 et seq.).