Haw. Rev. Stat. § 157-42: Interstate and federal compacts.

The board of agriculture and biosecurity may confer with authorities of other states and of the United States with respect to uniform milk control with states or as between states, and with the federal government in its control of prices of milk handled in interstate commerce, and may exercise its powers hereunder to effect uniform milk control. It may join with such other authorities, federal and state, in conducting joint investigations, holding joint hearings, and issue joint or concurrent orders, or orders supplementary to those of the federal government, and shall have the power to employ or designate a joint agent or joint agencies to carry out and enforce such joint, concurrent, or supplementary orders.