(a) Nothing contained in this part shall prevent the State from:
(1) Entering into voluntary agreements with any owners or operators of commercial passenger vessels, or their representatives, for the purpose of controlling pollution outside the marine waters of the State; or
(2) Adopting pollution controls more stringent than those contained in this part.
(b) The department may engage in efforts to encourage and recognize superior environmental protection efforts made by the owners or operators of commercial passenger vessels that exceed the requirements established by law.