Commissioned officers may, with the consent of the Secretary of State, be regularly and officially attached to the diplomatic missions of the United States in those nations with which the United States is extensively engaged in maritime commerce. Expenses for the maintenance of such Coast Guard attachés abroad, including office rental and pay of employees and allowances for living quarters, including heat, fuel, and light, may be defrayed by the Coast Guard.
14 U.S. Code § 711 - Coast Guard officers as attachés to missions
Experience since the war has indicated the necessity for making provision for the assignment of Coast Guard officers to diplomatic missions in those foreign countries which are extensively engaged in maritime commerce with the United States. This is largely the result of duties in connection with inspection of merchant vessels.
This section authorizes the designation, with the consent of the State Department, of Coast Guard officers to be officially attached to diplomatic missions of the United States. Although Coast Guard advice on Coast Guard matters is always available to our diplomatic missions, in those locations where such advice and information are frequently sought, it is felt that the most effective utilization of Coast Guard services would be achieved by having Coast Guard officers attached to such missions. Provision for customs officers to be attached to diplomatic missions is contained in the act of March 4, 1923, as amended, 42 Stat. 1453 (title 19, U.S.C., 1946 ed., § 6). Before the transfer in 1939 of the Foreign Agriculture Service to the State Department, representatives of the Bureau of Agricultural Economics of the Department of Agriculture stationed abroad were agricultural attachés. Act of June 5, 1930, 46 Stat. 498 (title 7, U.S.C., 1946 ed., § 542(a)). 81st Congress, House Report No. 557.