The director is hereby authorized to have trained and employed at the rescue stations, operated by the office within the state, such rescue crews as he or she may deem necessary. Each member of a rescue crew shall devote four hours each month for training purposes and shall be available at all times to assist in rescue work at explosions and mine fires. Regular members shall receive for such services the sum of $32 per month, and captains shall receive $35 per month, payable on requisition approved by the director. The director may remove any member of a rescue crew at any time.