Every employer, or where appropriate (in the case of records verifying the workers' disabilities) the referring agency or facility, of workers employed under special minimum wage certificates shall maintain and have available for inspection records indicating:

(a) Verification of the workers' disabilities;

(b) Evidence of the productivity of each worker with a disability gathered on a continuing basis or at periodic intervals (not to exceed six months in the case of employees paid hourly wage rates);

(c) The prevailing wages paid workers not disabled for the job performed who are employed in industry in the vicinity for essentially the same type of work using similar methods and equipment as that used by each worker with disabilities employed under a special minimum wage certificate (see also § 525.10(b) and (d));

(d) The production standards and supporting documentation for nondisabled workers for each job being performed by workers with disabilities employed under special certificates; and

(e) The records required under all of the applicable provisions of part 516 of this title, except that any provision pertaining to homeworker handbooks shall not be applicable to workers with disabilities who are employed by a recognized nonprofit rehabilitation facility and working in or about a home, apartment, tenement, or room in a residential establishment. (See § 525.15) Records required by this section shall be maintained and preserved for the periods specified in part 516 of this title.