PITTSBURGH (AP) — Steelmaker ArcelorMittal is "carefully reviewing" claims by the activist group PennEnvironment that its coke plant in the Pittsburgh suburbs is violating federal Clean Air Act standards by showering nearby residents with soot and other pollutants. The group on Tuesday announced sending a notice letter detailing the alleged violations to the steelmaker. PennEnvironment's executive director David Masur says the notice gives ArcelorMittal 60 days to address the alleged violations, otherwise the group will sue.