Exposure to triclosan in personal product use is relatively short. Upon disposal, triclosan is sent to municipal sewage treatment plants, where, in the United States, about 97–98% of triclosan is removed. Studies show that substantial quantities of triclosan (170,000–970,000 kg/yr) can escape from wastewater treatment plants and damage algae on surface waters. In a study on effluent from wastewater treatment facilities, approximately 75% of triclocarban was present in sewage sludge. This poses a potential environmental and ecological hazard, particularly for aquatic systems. The volume of triclosan, in the United States, re-entering the environment in sewage sludge after initial successful capture from wastewater is 44,000 ± 60,000 kg/yr. Triclosan can attach to other substances suspended in aquatic environments, which potentially endangers marine organisms and may lead to further bioaccumulation. Ozone is considered to be an effective tool for removing triclosan during sewage treatment. As little triclosan is released through plastic and textile household consumer products, these are not considered to be major sources of triclosan contamination.