Upon complaint being made to the director by any person operating in any oil field that there is occurring or threatened an unreasonable waste of gas in any field or fields, and when a petition is filed with the director requesting that a hearing be held to consider whether such waste is occurring or threatened, if it appears to the director that there is probable cause for such complaint, he shall order the supervisor to hold such a hearing and to fix a time and place therefor. A hearing may also be ordered by the director on the application of the supervisor.