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U. S. Steel and �����ֵͶע™ Launch COASTALUME™ Product, North America’s First GALVALUME® Solution Engineered and Warrantied for Coastal Environments

Combines U.S. Steel’s GALVALUME^® with �����ֵͶע™Tedlar^® PVF Film to withstand challenges associated with America’s coastal environment

Pittsburgh, Pa. & Wilmington, Del., Oct. 17, 2023 – United States Steel Corporation (NYSE: X) (“U. S. Steel”) and �����ֵͶע (NYSE: DD) today launched COASTALUME™, North America’s first GALVALUME^® material designed and warrantied for coastal environments. Marking a collaboration of two iconic American industry leaders, the new COASTALUME™ product combines the strength and self-healing characteristics of U. S. Steel’s GALVALUME^® material with �����ֵͶע^TM Tedlar^® PVF film barrier that withstands saltwater corrosion, UV damage, cracking, impact, and more.

Today, nearly 40 percent[] of Americans live in coastal counties and increasingly face unpredictability and damage caused by environmental factors like hurricane force winds and saltwater spray. By combining these two materials for the first time, U. S. Steel and �����ֵͶע have built a maintenance-free roofing solution that offers a level of durability and reliability needed in residential and commercial construction along the coast. The addition of a best-in-class warranty along with a timeless aesthetic, including a wide variety of color and finish options, further elevates steel options for builders, architects, and homeowners alike.

“American-made steel stands above steel made anywhere else, and steel is infinitely recyclable, unlike other building materials,” said Robert Kopf, Vice President Sales and Marketing, at U. S. Steel. “With our new product COASTALUME™ we were able to combine our steel with the proven performance and durability of �����ֵͶע™ Tedlar^® PVF film, and fully address the unique needs of coastal construction, which must withstand the toll that wind and saltwater inflict over time. This was engineered to address that need head-on.”

Applied directly to the steel coil, Tedlar^® film excels in resisting sea water and salt spray, maintaining color integrity even in prolonged sun exposure. Available in over 30 different colors, including metallics, wood grains, and stone finishes, its combination of durability and versatility is unmatched.

“�����ֵͶע invented Tedlar^® over six decades ago, and today it remains the industry gold standard in protection because of its flexibility, durability, and reliability,” said Matt Urfali, Vice President Sales and Marketing, �����ֵͶע™ Tedlar^®. “Tedlar’s performance and ease of maintenance have rightfully driven several exciting applications over the years, including use by the solar industry, aerospace, and even NASA. Now, by combining the resilience and flexibility of Tedlar^® with the strength of U. S. Steel’s GALVALUME^® material, this is the next breakthrough for the demanding construction market along the coast.”

COASTALUME™’s product warranty uniquely covers roofing and siding products installed up to 300 feet from breaking surf, large bays, marshes, and other coastlines. The exclusive warranty also covers up to 50 years for finish warranty and 25 years for substrate, another industry best.

�����ֵͶע and U. S. Steel have more than 340 years of combined science and manufacturing excellence in the United States. COASTALUME™ product will be unveiled at the 2023 METALCON Industry Trade Show, being held October 18-20 in Las Vegas, NV, by representatives from both U. S. Steel and �����ֵͶע. GALVALUME^® material is a registered trademark of BIEC International Inc.

About U. S. Steel

Founded in 1901, United States Steel Corporation is a leading steel producer. With an unwavering focus on safety, the Company’s customer-centric Best for All℠ strategy is advancing a more secure, sustainable future for U. S. Steel and its stakeholders. With a renewed emphasis on innovation, U. S. Steel serves the automotive, construction, appliance, energy, containers, and packaging industries with high value-added steel products such as U. S. Steel’s proprietary XG3™ advanced high-strength steel. The Company also maintains competitively advantaged iron ore production and has an annual raw steelmaking capability of 22.4 million net tons. U. S. Steel is headquartered in Pittsburgh, Pennsylvania, with world-class operations across the United States and in Central Europe. For more information, please visit .

About �����ֵͶע

�����ֵͶע (NYSE: DD) is a global innovation leader with technology-based materials and solutions that help transform industries and everyday life. Our employees apply diverse science and expertise to help customers advance their best ideas and deliver essential innovations in key markets including electronics, transportation, construction, water, healthcare and worker safety. More information about the company, its businesses and solutions can be found at . Investors can access information included on the Investor Relations section of the website at investors.dupont.com.

For further information contact:

Amanda Malkowski

U.S. Steel Media Relations Manager

Corporate Communications

(412) 736-2475

almalkowski@uss.com

Mary Ellen Broderick

�����ֵͶע Marketing Communications & Media Manager

Marketing Communications

(248) 243-1761

maryellen.broderick@dupont.com