Cameroon has 18 national parks and equivalent protected areas covering about 2 million hectares (6 million acres), about 4.4% of the country. Nevertheless, poaching is a major problem because of insufficient guards. Destruction of the remaining forests is heavy, even within reserved lands. Fires and commercial exploitation of the forests result in the elimination of 200,000 hectares (494,200 acres) per year. Overgrazing is degrading the semiarid northern range lands. By the mid-1980s, Cameroon had lost 40% of its mangrove swamps. Air pollution is a significant environmental problem in Cameroon. The main sources of pollution are industrial chemicals and vehicle emissions. Cameroon has 268 cu km of renewable water resources. About 78% of urban dwellers and 39% of the rural residents have access to safe drinking water. Poaching and overfishing threaten the nation's wildlife. As of 1994, the drill and Preuss's red colobus were endangered species. In a total of 409 mammal species, 32 are threatened with extinction. Of 690 bird species, 14 are endangered. Three reptiles, one amphibian, and 26 species of freshwater fish are also threatened. About 67 plant species of over 8,000 were endangered as of 2000.
The country also has a problem with volcanic activity, flooding, and insect infestation. In August 1986, poisonous gases emanating from Lake Nyos in northwestern Cameroon killed 1,746 villagers, by official count. The lake lies within the crater of a dormant volcano, and scientists speculated that the toxic gases were released by molten rock that had seeped into the lake.