Otay Mountain has had several wildfire incidents in the past. The plant life in Otay Mountain "burned completely" in 2003, and another wildfire happened later in 2007.[6]
A border fence spanning the Mexico–United States border runs along the south face of Otay mountain in order to prevent illegal immigrants from crossing the national border. The border fence has received criticism for its effects on nature and wilderness.[7] In particular, the construction was criticized by author Rob Davis for creating a harsh environment for a species of butterfly due to dust being kicked up by trucks.[8] The fence in the area is estimated to cost approximately $16 million per mile.[9]