These include chemical pesticides, bacteria, arsenic, dioxins, and polychlorinated biphenyls (PCB). This process is similar to induction of CYP1A1 by certain polychlorinated biphenyls and dioxins. When burned, they form even more toxic products, such as chlorinated dioxins and chlorinated dibenzofurans. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke. Other persistent toxins are PCBs, DDT, pesticides, furans, dioxins and phenols. Examples of persistent toxins are PCBs, DDT, TBT, pesticides, furans, dioxins, phenols, and radioactive waste. The EPA has not regulated levels of environmentally toxic manmade dioxins. They are the only bacteria known to transform highly chlorinated dioxins, PCBs. Bleaching with chlorine produces large amounts of organochlorine compounds, including dioxins. In the case of dioxins, these substances are considered very toxic and cancerous. These noxious fumes include dioxins and furans. The fires released small amounts of toxins, including cancer-causing dioxins. TEFs exist for seven congeners of dioxins, ten furans and twelve PCBs. Some PCBs share a structural similarity and toxic mode of action with dioxins. He was also to discover that toxic dioxins were there.