DDT was first used as an insecticide in the 1930s and was ultimately banned in 1972 because of its tendency to linger in the environment and its effect on wildlife, outlined by Rachel Carson in her 1962 book, Silent Spring. Developed by Bayer in the 1980s, neonicotinoids were designed to be much safer but are now being criticized for the same concerns. In 2012, the neonics were implicated in bee Colony Collapse Disorder. Recently, high concentrations of Bayer's chemical imidacloprid have been found in a Netherlands study to correlate with declines of bird populations. Bayer denies there is a cause and effect, but environmental groups are petitioning the EPA for a ban.¿