Chemical waste includes both the chemical byproducts of large manufacturing facilities and laboratories, as well as the smaller-scale solvents and other chemicals disposed of by households. It may fall under the classification of hazardous waste, depending on the nature of the chemicals — for example, chemicals such as ethanol and glycerol don’t require special disposal procedures. Health and safety legislation varies internationally and dictates the manner in which this waste must be handled and disposed of. In the United States, it is regulated by the Resource Conservation and Recovery Act as well as the Clean Water Act; while the Control of Substances Hazardous to Health Regulations (COSHH) regulates chemical waste in the UK.
If chemical waste is not handled or disposed of properly, both the environment and nearby individuals are put at risk by its potentially corrosive, toxic, flammable or explosive nature. Proper handling of this waste first requires the separation of chemicals that may react with one another, such as salts from acids, hypochlorites and hydroxides from ammonia, and oxidizing substances from combustible substances. After it is properly separated, it should be safely stored in tightly-sealed drums, bottles, tins or jars that will not be corroded or otherwise affected by the contents.
Special disposal services are usually contracted by the manufacturing facilities that produce chemical waste to have it removed in a manner that complies with health and safety regulations. It is then transported to a special disposal facility, where it is eliminated according to its compound substance or substances. Most chemical waste, including chlorinated solvents, are incinerated at a high temperature, while others are treated by wet chemical methods. After it has been incinerated or treated by wet chemistry, the residues are then safe to dispose of in a landfill.
The repercussions of improper chemical waste disposal often receive a high level of media coverage, particularly when the manufacturing plant or facility demonstrates deliberate negligence. For example, the Hooker Chemical Company of New York disposed of its waste in an incomplete canal and covered over the land before selling it for $1 US Dollar (USD) to the Niagara Falls city school board. In 1977, residents were evacuated after chemical leakage was detected on the site, which by that time featured a school and residential subdivision.