Bulgaria's air pollution problem results from the combined influence of industry and transportation. In the mid-1990s, Bulgaria was among the 50 countries with the highest industrial emissions of carbon dioxide, producing 54.3 million metric tons, or 6.08 metric tons per capita. In 1996, the total was 55.2 million metric tons. Twenty-five percent of Bulgaria's forests have been significantly damaged by airborne pollutants. Only 4.5% of the country's total land area is protected. Bulgaria's rivers and the Black Sea are seriously affected by industrial and chemical pollutants, raw sewage, heavy metals, and detergents. However, nearly 100% of the population have access to safe drinking water. Industrial pollutants, especially from metallurgical plants, are responsible for damage to 115 sq mi of land in Bulgaria. Endangered species in Bulgaria include the Rosalia longhorn, Atlantic sturgeon, and slender-billed curlew. As of 2001, there were 13 mammal species, 12 bird species, 1 reptile species, and 59 plant species that were endangered.