These chemicals were banned in the U.S. in 1979 amid suggestions that PCBs could have unintended impacts on human and environmental health. From the 1920s until their ban, an estimated 1.5 billion pounds of PCBs were made for things such as microscope oils, electrical insulators, capacitors, and electric appliances such as television sets or refrigerators. PCBs were also sprayed on dirt roads to keep the dust down prior to knowing some of the unintended consequences from widespread use. ...