15. The chief inspector, when he deems it warranted by the circumstances and in order to make up unavoidably lost time or to satisfy the exigencies of industry, may extend, for a period of time not exceeding eight weeks, the periods of employment of members of the personnel less than eighteen years of age, to fifty-five hours in a week provided that work shall not commence before seven hours or extend beyond twenty-one hours.
R. S. 1964, c. 150, s. 17; 1968, c. 46, s. 8; 1975, c. 49, s. 8.