43 C.F.R. § 421.2 Preservation of property.
Title 43 - Public Lands: Interior
The following are prohibited: The improper disposal of rubbish; the creation of any hazard to persons or things; the throwing of articles of any kind from the roadway, walks, or guardrails across the top of the dam, from the parking areas or visitor observation points, or from any other structure or building; the climbing upon the guardrails of the dam or upon the roof or any part of any building or structure; and the willful destruction, damage, or removal of property or any part thereof.
Title 43: Public Lands: Interior
PART 421—RULES OF CONDUCT AT HOOVER DAM
§ 421.2 Preservation of property.

