(1) The laboratory must notify the customer of the subcontract arrangement in writing, including the subcontractors' accreditation credentials under chapters 69.50 RCW and 314-55 WAC.

(2) The laboratory must maintain a register of all subcontractors that it uses for tests and/or calibrations and a record of the evidence of compliance with chapter 314-55 WAC for the work in question.

(3) When there are indications that subcontractors knowingly supplied items or services of substandard quality, this information must be forwarded to laboratory management for corrective action.