Wash. Rev. Code § 70A.222.040
A certificate of compliance stating that a package or packaging component is in compliance with the requirements of this chapter shall be developed by its manufacturer. For food packaging, a manufacturer shall develop a compliance certificate by the date of a prohibition taking effect under RCW 70A.222.070. If compliance is achieved under the exemption or exemptions provided in RCW 70A.222.030, the certificate shall state the specific basis upon which the exemption is claimed. The certificate of compliance shall be signed by an authorized official of the manufacturing company. The certificate of compliance shall be kept on file by the manufacturer for as long as the package or packaging component is in use, and for three years from the date of the last sale or distribution by the manufacturer. Certificates of compliance, or copies thereof, shall be furnished to the department of ecology upon request within sixty days. If manufacturers are required under any other state statute to provide a certificate of compliance, one certificate may be developed containing all required information.
If the manufacturer or supplier of the package or packaging component reformulates or creates a new package or packaging component, the manufacturer shall develop an amended or new certificate of compliance for the reformulated or new package or packaging component.
RCW 70A.222.040