PCBs, or polychlorinated biphenyls, have been used extensively in electrical equipment such as transformers and large capacitors in power lines and in additives in paint, carbonless copy paper and plastics. They are one of 12 highly toxic chemicals targeted for elimination by the Stockholm Convention on Persistent Organic Pollutants that entered into force last month. UNEP Executive Director Klaus Toepfer said the financial and technical challenges of eliminating PCBs from the planet will require a “vigorous” public-private partnership. “While international donors and national governments will set priorities and invest tens of millions of dollars, commercial firms have the expertise and technologies to perform much of the actual clean-up work,” he said. Many hundreds of thousands of tons of PCBs have been commercially manufactured for some 75 years. Although production is now banned under the Stockholm treaty, PCBs continue to pose a risk to human health and the environment because of the wide array of PCB-containing electrical equipment still in service. Tons of wastes containing or contaminated by PCBs are also being held at temporary storage sites, particularly in developing countries, according to UNEP. In addition, large quantities of PCBs have been discharged into soils, rivers and lakes over the years. Further releases continue to result due to accidents, the repair and decommissioning of equipment, the demolition of buildings and the continued existence of imperfectly sealed landfills and waste drums, the agency said. The Convention, which entered into force on 17 May, gives governments until 2025 to phase out “in-place equipment” containing PCBs, as long as the equipment is maintained in a way that prevents leaks. It also grants another three years to ensure the environmentally sound management of PCB-contaminated wastes.