Hydro Extrusion USA pleaded guilty on Tuesday in federal court in Portland to Clean Air Act violations at its aluminum processing facility in The Dalles.  According to the U.S. Attorney’s office in Portland, from July 2018 through June 2019, Hydro acquired and melted scrap aluminum coated in a mineral-oil based mixture that, when combusted, produced hazardous smoke.  Under the Clean Air Act, secondary aluminum production facilities are only permitted to use “clean charge,” which is aluminum scrap free of paints, coatings or lubricants.  Hydro Extrusion, which is based in North America in Rosemont, Illinois, pleaded guilty to negligent endangerment by discharging a hazardous pollutant, which is punishable by of fine of up to $200,000 or twice the gross gains or losses resulting from the offense.  The U.S. Attorney’s office says Hydro fully cooperated with the federal government investigation of the matter and agreed to plead guilty and to pay $550, 125 prior to sentencing, which will occur on April 24 before U.S. District Court Judge Michael Mosman.