(1) A synthetic liner may be used to meet the applicable standards set forth in WAC 16-229-030.

(2) Synthetic liners shall be chemically compatible with the materials being stored within the permanent storage facility and have a minimum thickness of 30 mils +/- 1 mil. A written confirmation of compatibility and a written estimate of the life of the liner from the manufacturer shall be kept on file at the permanent storage facility or the nearest local office from which the permanent storage facility is administered.

(3) Synthetic liners shall be installed under the supervision of a qualified representative of the manufacturer, a contractor certified by the manufacturer, or a certified engineer. All field constructed seams shall be tested, and repaired if necessary, in accordance with the manufacturer[']s recommendations.