Any public service company subject to regulation by the commission as to rates and service may make or contract for any rejected item of expenditure, but in such case the rejected item of expenditure shall not be allowed as an operating expense, or as to items of construction, as a part of the fair value of the company's property used and useful in serving the public: PROVIDED, That such items of construction may at any time thereafter be so allowed in whole or in part upon proof that they are used and useful. Any company may upon the happening of any emergency caused by fire, flood, explosion, storm, earthquake, riot, or insurrection, or for the immediate preservation or restoration to condition of usefulness of any of its property, the usefulness of which has been destroyed by accident, make the necessary expenditure therefor free from the operation of RCW 81.04.300 through 81.04.330.

Any finding and order entered by the commission is effective until vacated and set aside in proper proceedings for review thereof.