50 CFR 27.94: Disposal of waste.

(a) The littering, disposing, or dumping in any manner of garbage, refuse sewage, sludge, earth, rocks, or other debris on any national wildlife refuge except at points or locations designated by the refuge manager, or the draining or dumping of oil, acids, pesticide wastes, poisons, or any other types of chemical wastes in, or otherwise polluting any waters, water holes, streams or other areas within any national wildlife refuge is prohibited.

(b) Persons using a national wildlife refuge shall comply with the sanitary requirements established under the provisions of this subchapter C for each individual refuge; the sanitation provisions which may be included in leases, agreements, or use permits, and all applicable Federal and State laws.