PCB is the common name for a group of over 200 chemical compounds that are non-flammable when subjected to high temperatures. They range from light and oily to compounds with the consistency of heavy grease or wax. Over 70 years ago, they were found to be excellent lubricants and coolants for transformers and other electrical equipment. They were so successful in reducing fire hazards that many city codes were changed over the years to require that they be used in place of mineral oil in transformers.
Manufacturers that used PCBs, like General Electric, dumped PCB waste into waterways for years. Concentrations began turning up in fish, but no adverse health effects attributed to them were noticed until 1968, when some 1,300 Japanese became ill after using cooking oil that had been contaminated by leakage from an air conditioning system. The victims suffered nausea, fatigue, swelling of the extremities, skin rashes and liver disorders.
The first press reports said the contaminant was PCBs, but further research found that subjecting the PCBs to extremely high temperatures had changed them from polychlorinated biphenyls into PCDFs, polychlorinated dibenzofurans, which are very toxic. In the wake of the Japanese incident, the EPA ordered animal tests to determine if PCBs were carcinogenic. The tests involved feeding rats very large doses of a PCB made by Monsanto called Aroclor 1260. It had a chlorine content of 60 percent, which is relatively high. It and other highly-chlorinated PCBs accounted for about 12% of the PCBs sold in the U.S. The tests resulted in cancerous tumors of the liver.
This did not constitute proof that eating fish with traces of PCBs would cause cancer in human beings, but that was the interpretation radical environmentalists placed upon the findings. Legislation was pushed through Congress that called for an immediate ban on PCBs, which proved to be impossible given their widespread use in electrical systems throughout the country. The industry first had to develop substitutes for PCBs. In the meantime, the assumption that PCBs posed a cancer risk for humans was seriously challenged.
Thousands of industrial workers had been exposed to high concentrations of PCBs on their jobs during the 1950s through the 1970s. Many of them routinely used PCBs to clean grease off their hands. In 1981, an OSHA epidemiological study of 2,500 workers, half of whom had been exposed to PCBs for over 17 years, found that the number of deaths from cancer was 10 percent lower than what would be expected for a group with the same profile in the general population. There was no relationship between the length of time in PCB- exposed jobs and the risk of death due to cancer, cardiovascular disease, and neurological manifestations or from any other causes.
A 1984 German study found that rats given high daily doses of PCBs with a 60% chlorine content developed liver tumors in their old age, the same result obtained by EPA. But the Germans also tested PCBs with a chlorine content of 42% and found that the rats had fewer total cancers than a control group which was not exposed to any PCBs. In 1991, the Institute for Evaluating Health Risks, IEHR, reconstructed five rat tests that led to the ban. It found that PCBs with chlorine content below 60% showed no "statistically significant elevations of liver tumors" in rats. The IEHR study, signed by former EPA acting administrator John A. Moore, stated, "The current cancer policy is clearly overstating the cancer risks associated with many exposures to PCBs in the environment." EPA's regulatory decisions, he said, are causing "a major economic impact for, at best, trivial public health gain."
Environmentalists are fighting plans to dredge the Delaware River to deepen it. They say it will release pollutants that are now covered by sediment and that the disposal sites can be a source of pollution for the river in the future. PCB levels in upper Hudson River water have declined 90 percent since 1977. It is now safe for swimming and as a source of treated drinking water. Dredging the Hudson will be half a billion dollars down the drain for not even a trivial public health gain.
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