Wash. Rev. Code § 18.71B.140
(4) The officers and employees of the interstate commission shall be immune from suit and liability, either personally or in their official capacity, for a claim for damage to or loss of property or personal injury or other civil liability caused or arising out of, or relating to, an actual or alleged act, error, or omission that occurred, or that such person had a reasonable basis for believing occurred, within the scope of interstate commission employment, duties, or responsibilities, provided that such person shall not be protected from suit or liability for damage, loss, injury, or liability caused by the intentional or willful and wanton misconduct of such person.
[ 2017 c 195 s 14.]