Polychlorinated Biphenyls (PCBs)
Polychlorinated biphenyls (PCBs) are man made (synthetic) chemical compounds consisting of chlorine, carbon and hydrogen. Commercial manufacturing of PCBs began in the United States in 1929. The manufactured chemical is know by a variety of brand names including but not limited to Aroclor, Askarel, Eucarel, Pyranol, Dykanol, Clorphen, Clorinol, Chlorextol, Diaclor, Hyvol, Inerteen, Elemex, Saf-T-Kuhl, No-Flanol, Nepolin, EEC-18, and many others.
PCBs are very stable, relatively fire-resistant, do not conduct electricity, have low volatility at normal temperatures, and are insoluble in water. These unique physical and chemical properties made PCBs a desirable ingredient in a wide variety of commercial and industrial products including hydraulic fluid, casting wax, pigments, carbonless copy paper, plasticizers, vacuum pumps, compressors, heat transfer systems and many other applications. The primary use of PCBs, however, was as a dielectric fluid in electrical equipment particularly in transformers and capacitors. Standard fluorescent light fixtures manufactured prior to 1979 typically have PCB containing capacitors in their ballasts. Occasionally the capacitors leak and PCB fluid contaminates the tar like potting material within the ballast.
Initially, there were very few concerns regarding the use of PCB compounds. Environmental concerns and health hazard warnings first surfaced in the late 1960s with the discovery of PCB accumulation in the bodies of birds in Sweden, and the poisoning of over 1200 people in Japan from food cooked in rice oil contaminated with PCBs and other chemicals. By 1972, scientific evidence suggested that PCBs posed a potential hazard to the environment and to human health. There have been numerous studies trying to determine the human health effects associated with PCB exposure, but to date none of these studies has been conclusive. There are many conflicting medical opinions, some believe that short-term low-level exposure is not a serious concern, but there is a widespread concern regarding long-term exposure to even low concentrations of PCBs. Canada banned the use of PCBs in 1980, however, there are still large quantities of PCBs in service and in storage, (primarily in electrical equipment, such as transformers and capacitors).
Significant quantities of PCBs have dissipated in the environment due to historical uncontrolled use and dumping. The compound invariably finds its way into waterways contributing to PCB contamination of rivers, oceans, soils and even the polar ice cap. The extreme resistance to chemical and biological breakdown that made PCBs so useful in industrial applications allows the compound to accumulate in living organisms including the human body. This bioaccumulation and concern over the contamination of the food chain is one of the reasons that PCBs have become a health and environmental issue.
The scientific community generally agrees that the best long-term solution to the PCB problem is to destroy the remaining stores of PCBs that have not yet dispersed into the environment. There are various options for treatment available including chemical stabilization. The Government of Canada has chosen to destroy liquid PCBs primarily through high temperature incineration (greater than 1200°C). Our federal and provincial governments have both enacted specific legislation and regulations to control PCB use, importation, manufacture, handling, storage, transportation and destruction.
Fluorescent light ballast capacitors may contain about an ounce of PCBs; a utility pole capacitor or transformer may contain much more. Generally, most capacitors manufactured prior to 1979 will contain PCBs, newer non-PCB equipment is typically designated with a “No PCBs” label. If the component is not clearly labeled as “Non PCB” then it should be assumed to contain PCBs. The classification, safe handling, cleanup, transportation, and destruction of PCBs is a complicated procedure that falls under the jurisdiction of a number of federal, provincial, and in some cases municipal authorities. Even a small spill or other release into the environment could result in an expensive clean up bill for the generator. The details of PCB handling, management, and ultimate destruction should be trusted to the experts, it is important to choose a contractor that has the experience and expertise to do the job safely and properly.
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