There may be licensed, in no greater number in each of the counties of the state than as the board shall deem advisable, retail outlets established for the purpose of making cannabis concentrates, useable cannabis, and cannabis-infused products available for sale to adults aged twenty-one and over. Retail sale of cannabis concentrates, useable cannabis, and cannabis-infused products in accordance with the provisions of this chapter and the rules adopted to implement and enforce it, by a validly licensed cannabis retailer or retail outlet employee, shall not be a criminal or civil offense under Washington state law.