Chlorine dioxide is a chemical compound with the formula ClO2 that exists as a yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is used as a disinfectant similar to bleach and is effective at killing bacteria, viruses, and fungi. Chlorine dioxide is used for bleaching of wood pulp, disinfection of municipal drinking water, treatment of water in oil and gas applications, disinfection in the food industry, microbiological control in cooling towers, and textile bleaching. It is also used as an oxidant for destroying phenols in wastewater streams and for odor control in the air scrubbers of animal byproduct (rendering) plants. Chlorine dioxide is soluble in water and will react rapidly with other compounds. When it reacts in water, it forms chlorite ion, which is also a very reactive chemical. However, it is unsafe when used in large amounts and can cause serious side effects, including severe vomiting, liver failure, and death. Very dilute amounts of chlorine dioxide are used in public water treatment facilities to disinfect water, but the US FDA has warned consumers that chlorine dioxide supplement products are unsafe.