Most of the impact that humans have had on the environment of Alaska has been by military testing, oil drilling, and lumber industries. During World War 2, Alaska was used as a nuclear, chemical, and biological warfare testing program. On the Aleutian Island of Amchitka, the U.S. Atomic Energy Commision detonated three nuclear blasts between 1965-1971, including the world's largest underground nuclear test. Department of Defense policy has been to leave contamination in place, relying on institutional controls such as fences and signs to "prevent" exposures to toxic chemicals. Many of these sites have significant PCB contamination in addition to massive fuel spills, solvents, herbacides/pesticides, heavy metals, chemical warfare materials, and radioactive waste.
Alaska is also a huge source for oil. Spills of oil and various other toxic substances are a chronic problem in the oil fields. Nearly 400 spills occur annually from oil industry activities. Diesal fuel wreaks havoc on plant life. A study of diesal spills in Alaska's Arctic found that 28 years later there were still substantial hydrocarbons in the soil and little vegetation recovery. Chronic effects of PAH's (polycyclic aromatic hydrocarbons) can harm populations of pink salmon and other fish through sterility in adults and toxicity of larvae. Just one drop of fresh crude oil can kill the embryo of a bird's egg.
Most of these spills occur on the coast but now the U.S. government is considering tapping oil reserves that are within the Arctic National Wildlife Refuge which is in the Interior area of Alaska. This can potentially devastate the wildlife in that area.
