Editing Polychlorinated biphenyl (section)

==Production==
One estimate (2006) suggested that 1&nbsp;million tonnes of PCBs had been produced. 40% of this material was thought to remain in use.<ref name=Ullmann/> Another estimate put the total global production of PCBs on the order of 1.5&nbsp;million tonnes. The United States was the single largest producer with over 600,000 tonnes produced between 1930 and 1977. The European region follows with nearly 450,000 tonnes through 1984. It is unlikely that a full inventory of global PCB production will ever be accurately tallied, as there were factories in Poland, East Germany, and Austria that produced unknown amounts of PCBs. {{As of|2002}}, there were still 21,500 tons of PCBs stored in the easternmost regions of Slovakia.<ref>{{cite journal | vauthors = Breivik K, Sweetman A, Pacyna JM, Jones KC | title = Towards a global historical emission inventory for selected PCB congeners—a mass balance approach. 1. Global production and consumption | journal = The Science of the Total Environment | volume = 290 | issue = 1–3 | pages = 181–198 | date = May 2002 | pmid = 12083709 | doi = 10.1016/S0048-9697(01)01075-0 | bibcode = 2002ScTEn.290..181B }}</ref>

Although deliberate production of PCBs is banned by international treaty, significant amounts of PCBs are still being "inadvertently" produced. Research suggests that 45,000 tons of 'by-product' PCBs are legally produced per year in the US as part of certain chemical and product formulations.<ref>{{Cite news |last1=Salvidge |first1=Rachel |last2=Hosea |first2=Leana |date=2024-03-08 |title=Cancer-causing PCB chemicals still being produced despite 40-year-old ban |url=https://www.theguardian.com/environment/2024/mar/08/cancer-causing-pcb-chemicals-still-produced-despite-40-year-old-ban |access-date=2024-03-08 |work=The Guardian }}</ref><ref>{{cite journal |last1=Megson |first1=David |last2=Idowu |first2=Ifeoluwa Grace |last3=Sandau |first3=Courtney D. |title=Is current generation of polychlorinated biphenyls exceeding peak production of the 1970s? |journal=Science of the Total Environment |date=May 2024 |volume=924 |pages=171436 |doi=10.1016/j.scitotenv.2024.171436 |pmid=38447728 |bibcode= 2024ScTEn.92471436M}}</ref>

Commercial production of PCBs was banned in the United States in 1979, with the passage of the [[Toxic Substances Control Act]] (TSCA).<ref name="epa">{{cite web|website=United States Environmental Protection Agency|title=Polychlorinated Biphenyls|date=April 12, 2023|url=https://www.epa.gov/pcbs/learn-about-polychlorinated-biphenyls}}</ref>