Wash. Rev. Code § 49.52.030
All moneys realized by any employer from the employer's employees either by collection or by deduction from the wages or pay of employees intended or to be used for the furnishing to workers engaged in extrahazardous work, their families or dependents, of medical, surgical or hospital care and treatment, or for nursing, ambulance service, burial or any or all of the above enumerated services, or any service incidental to or furnished or rendered because of sickness, disease, accident or death, and all moneys owing by any employer therefor, shall be and remain a fund for the purposes for which such moneys are intended to be used, and shall not constitute or become any part of the assets of the employer making such collections or deductions: PROVIDED, HOWEVER, That RCW 49.52.030 and 49.52.040 shall not apply to moneys collected or deducted as aforesaid for, or owing by employers to the state medical aid fund. Such moneys shall be paid over promptly to the physician or surgeon or hospital association or other parties to which such moneys are due and for the purposes for which such collections or deductions were made.
RCW 49.52.030