A chemical toilet is a toilet using chemicals to deodorize the waste instead of simply storing it in a hole, or piping it away to a sewage treatment plant. These toilets are most commonly found on airplanes, trains, caravans and motorhomes, identified with a blue-colored dye in the bowl water. (In the United States and Australia this blue liquid formula is generally called "Anotec".) An even simpler chemical toilet consists of a seat on a container or bucket of water, with a solution of chemicals used to disinfect or/and deodorize. These are sometimes found on inter-city buses or in homes where indoor plumbing is not available. Portable toilets are universally chemical toilets.
Disinfection was generally carried out by mixing formaldehyde or similar chemicals with the toilet water when flushed. Modern formulations are nitrate based and work biologically.
Since formaldehyde is very irritating to the skin, nose, and throat, it is being replaced by other proprietary blends such as glutaraldehyde and quaternary ammonium compounds, with non-staining dyes and nature-identical perfume oils. Also the use of enzyme hybrids are being developed now.