Mont. Code § 75-5-105
Except as provided in 80-15-108, any information concerning sources of pollution that is furnished to the board or department or that is obtained by either of them is a matter of public record and open to public use. However, any information unique to the owner or operator of a source of pollution that would, if disclosed, reveal methods or processes entitled to protection as trade secrets must be maintained as confidential if so determined by a court of competent jurisdiction. The owner or operator shall file a declaratory judgment action to establish the existence of a trade secret if the owner or operator wishes the information to remain confidential. The department must be served in the action and may intervene as a party. Any information not intended to be public when submitted to the board or department must be submitted in writing and clearly marked as confidential. The data describing physical and chemical characteristics of a waste discharged to state waters may not be considered confidential. The board may use any information in compiling or publishing analyses or summaries relating to water pollution if the analyses or summaries do not identify any owner or operator of a source of pollution or reveal any information that is otherwise made confidential by this section.
§ 75-5-105, MCA