One of the nation's most popular weed killers, the herbicide 2,4-D (also known as 2,4-dichlorophenoxyacetic acid) has been widely used by homeowners, timber companies, government agencies, farmers, and power companies to eliminate unwanted vegetation from lawns, golf courses, forests, rangelands, rights-of-way, pastures, highways, and even farmlands. Scientists and environmentalists have warned for years of the chemical's toxic effects, and Rachel Carson's classic book Silent Spring described its dangers to human health and the environment. Subsequent studies have linked 2,4-D to cancers, miscarriages, and birth defects in animals and humans who have been exposed to it. Agent Orange, a defoliant used during the Vietnam War, was a 50/50 mixture of 2,4-D and a similar herbicide, 2,4,5-T. For years environmentalists have urged that 2,4-D be banned or strictly controlled, but the U.S. Environmental Protection Agency (EPA) has so far not acted to do so.