LIABILITY OF A PRINCIPAL CONTRACTOR LIABLE FOR PREMIUMS DUE THE ACCIDENT AND MEDICAL AID FUNDS FOR EXTRA-HAZARDOUS WORK PERFORMED UNDER A SUB‑CONTRACTOR A principal contractor who lets a contract for extra-hazardous work shall be liable directly and primarily for the payment of premiums to the accident and medical aid funds for work performed under such contract, under the provisions of RCW 51.12.070, and such provision does not offend against Article 1, § 3 of the state constitution or the fourteenth amendment of the United States Constitution.