In the course of an investigation and request by the board under its authority in chapter 18.43 RCW, a licensee or registrant must provide access to any papers, records, or documents in their possession or accessible to them that pertain to the allegations in a complaint or investigation, and may provide a written explanation addressing such complaint/investigation or other information requested by the board. A facility related to a complaint or investigation shall be made accessible by the licensee during regular business hours.