Effluent from the Kawerau mill poured into the Tarawera River (shown here flowing into the ocean at Matatā, in the late 1990s). Environmental campaigners called it the ‘black drain’. The discolouration resulted from the chemical pulping process, pulp bleaching, and coloured paper production. When the government and Fletchers looked for a site for the Kawerau mill in the early 1950s the problem of effluent was one factor they considered. The location on the Tarawera River was seen as suitable because of the short distance between the effluent outfall and the river mouth.