Sixth Consecutive Year of Recognition PITTSBURGH, Dec. 16, 2025 /PRNewswire/ -- Koppers Holdings Inc. (NYSE: KOP), an integrated global provider of treated wood products, wood treatment chemicals and carbon compounds, has been named as one of America's Most Responsible Companies by Newsweek magazine for the sixth consecutive year for 2026. "We are honored to once again be named among America's Most Responsible Companies – a reflection of our employees' unwavering commitment to living out our values of Peopl ...