Polyhalogenated compounds (PHCs) are any compounds with multiple substitutions of halogens. They are of particular interest and importance because halogens generally are highly reactive and also bioaccumulate in humans, and comprise a superset of which has many toxic and carcinogenic industrial chemicals as members. PBDEs, PCB

Polychlorinated biphenyl

Polychlorinated biphenyls are a class of organic compounds with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for PCBs is C12H10-xClx...

s, dioxins (PCDDs) and PFC

Perfluorinated compounds

A perfluorinated compound is an organofluorine compound with all hydrogens replaced by fluorine on a carbon chain—but the molecule also contains at least one different atom or functional group. Thus, PFCs have properties similar to fluorocarbons as they are fluorocarbon derivatives...

s are all polyhalogenated compounds. They are generally non-miscible in organic solvents or water, but miscible in some hydrocarbons from which they often derive.

Uses

PHCs are used in a vast array of manufactured products, from wood treatments, to cookware coatings, to non-stick, waterproof, and fire-resistant coatings, cosmetics, medicine, electronic fluids, food containers and wrappings, in everything from furniture

Furniture

Furniture is the mass noun for the movable objects intended to support various human activities such as seating and sleeping in beds, to hold objects at a convenient height for work using horizontal surfaces above the ground, or to store things...

 and furnishings, automobiles, airplanes, plastics, clothing

Clothing

Clothing refers to any covering for the human body that is worn. The wearing of clothing is exclusively a human characteristic and is a feature of nearly all human societies...

 and cloth, surgery, insulation, adhesives, paints, sealants, lubricating oils, polyurethane foams, cancer therapy and medical imaging. They are also heavily used in pest control

Pest control

Pest control refers to the regulation or management of a species defined as a pest, usually because it is perceived to be detrimental to a person's health, the ecology or the economy.-History:...

.

Safety

PHCs include notoriously dangerous substances, including Agent Orange

Agent Orange

Agent Orange is the code name for one of the herbicides and defoliants used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. Vietnam estimates 400,000 people were killed or maimed, and 500,000 children born with birth...

, DDT

DDT

DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....

, and other pesticides. Many non-pesticide PHCs have the same safety issues as pesticides.

Types

• Polycholorinated, e.g. PCB
  Polychlorinated biphenyl
  Polychlorinated biphenyls are a class of organic compounds with 2 to 10 chlorine atoms attached to biphenyl, which is a molecule composed of two benzene rings. The chemical formula for PCBs is C12H10-xClx...
  
  s, dioxins (PCDDs), hexachlorophene
  Hexachlorophene
  Hexachlorophene, also known as Nabac, is a disinfectant. The compound occurs as a white to light-tan crystalline powder, which either is odorless or produces a slightly phenolic odor. In medicine, hexachlorophene is very useful as a topical anti-infective, anti-bacterial agent, often used in soaps...
  
  , dibenzofurans (PCDFs), polychloro phenoxy phenol
  Polychloro phenoxy phenol
  Polychloro phenoxy phenols are a group of organic polyhalogenated compounds. Among them include triclosan and predioxin, the former which can have trace amounts of dioxins and furans, and the latter which degrades to produce dioxins...
  
  s (PCPPs), polychlorinated diphenyl ethers
  Polychlorinated diphenyl ethers
  Polychlorinated diphenyl ethers are structurally similar to polychlorinated biphenyls , both which may be toxic polyhalogenated compounds and some PCDE congeners have been reported to cause toxic responses similar to those caused by some of the non-ortho-substituted PCBs, which are mediated by the...
  
   (PCDEs).
• Polybrominated, e.g., PBDE
  PBDE
  Polybrominated diphenyl ethers or PBDE, are organobromine compounds that are used as flame retardants. Like other brominated flame retardants, PBDEs have been used in a wide array of products, including building materials, electronics, furnishings, motor vehicles, airplanes, plastics,...
  
  s, polybrominated biphenyls (PBBs).
• Perflourinated compounds
• Polyiodinated compounds

Breakdown of Compounds

Despite bioaccumulating in humans, patents have been filed for removal of halogen by electrolysis during manufacturing, though toxic chlorinated compounds may be created as byproducts of chlorinated compounds. Another method during manufacture is to use anaerobic bacteria