The Biden administration has initiated a formal evaluation of risks posed by vinyl chloride, the cancer-causing chemical that burned in a towering plume of toxic black smoke following a fiery train derailment earlier this year in eastern Ohio. The Environmental Protection Agency will review risks posed by a handful of chemicals, including vinyl chloride, which is used to make a variety of plastic products, including pipes, wire and packaging materials. It is one of five chemicals the agency is reviewing, including four that are used to make plastics. Environmental and public health activists welcomed the announcement, calling the review long overdue. Advocates had called the toxic train derailment in East Palestine, Ohio, a warning that the U.S. must ban petrochemicals such as vinyl chloride.