CSN: Companhia Siderrgica Nacional S A : Comunicado ao Mercado Release ESG 4T24 e 2024

4Q24 - ESG PERFORMANCE LEADERSHIP IN ESG ISSUES With great enthusiasm, I share the progress and achievements of Companhia Siderúrgica Nacional in the fourth quarter of 2024, as well as other highlights throughout the year. Each result reflects our ongoing commitment to sustainability, safety, and social development. I am very proud of the transformations our team made in 2024, contributing to increasingly responsible production. In 2024, we achieved a historic record in environmental investments, totaling R$ 1.2 billion in CAPEX and OPEX. This amount reflects our commitment to responsible environmental management, with projects focused on emission reduction, water efficiency, waste reuse, and the modernization of industrial processes. Notably, we highlight the completion of the works for the decommissioning of the Taboquinha 2 dam at ERSA (RO), which is now moving into the legal monitoring phase. In our efforts to innovate the Company's decarbonization agenda, we completed the development of CBRAIN this quarter, a strategic climate management tool. The system provides an integrated view of indicators, projects, risks, and opportunities that contribute to decision-making by senior leadership. As a result of the continuation of our decarbonization journey projects, in 2024, we achieved a 7% reduction in emissions intensity in the steelmaking sector , 10% in mining , and 3% in cement production , compared to the baseline results of each target year. In occupational safety, as a result of the AGIR Program for preventing high-potential accidents, we celebrated a year without fatalities and a significant 66% reduction in the accident severity rate , compared to 2023, marking the best performance in the last 10 years. Advancing in the social field, we invested over R$ 66 million in social projects through the CSN Foundation and launched new initiatives aimed at strengthening female representation, such as the "Empodera" program, dedicated to increasing the number of women in leadership positions, and the "Women Who Transform Industry" campaign, highlighting inspiring journeys to encourage the participation of a new generation of women in industrial sectors. In line with the commitment made in 2020 to double the Company's gender representation by 2025, we reached the milestone of 25% women in our workforce , bringing us closer to our target of 28% by 2025, representing a 75% increase compared to 2020 (the baseline year for the goal). We maintained the excellent results achieved in 2023 in ESG ratings, solidifying our position among the industry's leading companies. CSN and CMIN remain ranked among the top 10% by S&P Global , and we hold the 13th and 8th positions, respectively, among 158 companies analyzed by Sustainalytics in the steel sector. Additionally, we received the "Industry Top Rated" seal from Sustainalytics, recognizing our performance as one of the leading ESG companies in the sector in 2024, and we maintained CSN and CMIN in the FTSE4Good index. It was, indeed, a year of many achievements! I invite you to explore the following pages of this release for more details about our initiatives and results. I wish everyone a great reading! Do well, Do more , Do it Forever. Helena Brennand Guerra Member of the Board of Directors of CSN Mining Director of Sustainability, Environment, Health and Safety, and Heritage at the CSN Group. ABOUT THIS REPORT Since the beginning of 2023, CSN has started to disclose its actions and performance, providing its ESG performance and indicators in a more individualized manner. This model allows stakeholders to access key results and indicators on a quarterly basis, enabling them to track progress in a more effective and timely manner. CSN awarded the "Industry Top Rated" seal. The company is ranked 13th out of 158 in the sector, while CMIN is ranked 8th . In the sectoral evaluation, CSN is positioned among the top 10% of companies , while CMIN stands out among the top 8%. The information included in this release has been selected based on its relevance and materiality for the Company. The quantitative indicators are presented in comparison with the period that best represents the Best Best 5% Best Best 8% metric for monitoring. More detailed historical data on the performance and initiatives of the CSN Group, as well as performance on other ESG targets, can be found in the Company's Integrated Report, available at Integrated Report - CSN . The assurance of ESG indicators is conducted annually for the closure of the Integrated Report, so the information in the quarterly releases may be subject to adjustments resulting from this process. It is also possible to track CSN's ESG performance on our website: https://esg.csn.com.br/ 8% CSN CMIN 28.1 24.4 2024 10% CSN CMIN 47 55 2024 ESG RATINGS External recognitions in indices and ratings highlight the continuous progress of the Company, showcasing our commitment to transparency regarding key Constantly improving our ESG performance, evolving from CCC to BB in two years . 3.4 3.4 practices and indicators aligned with sustainable development. The year 2024 was marked by significant achievements, positively reflected in the evaluation of internationally recognized ESG ratings. We maintained the excellent results achieved in 2023, positioning CSN and CMIN among the top 10% of companies in the sector in S&P Global , with the companies ranking 13th and 8th , respectively, among 158 companies assessed by Sustainalytics. CSN was awarded the " Industry Top Rated " seal by this agency in recognition of its performance as one of the leading ESG companies in the sector in 2024. Additionally, we maintained our BB rating with MSCI and were once again included in the FTSE4Good index . BB BB B CCC 2021 2022 2023 2024 2.5 2,9 CSN CMIN 2021 2022 2023 2024 ESG PERFOMANCE GOVERNANCE HEALTH AND SAFETY CSN recognized as Industry Top Rated (Sustainalytics). Completion of the Climate Vulnerability Study. Definition of the ESG Supply Chain Risk Matrix . Zero fatalities in 2024. A 66.3% reduction in the accident severity rate compared to 2023, the lowest rate in the last 10 years. A 63% reduction in lost days (both direct and third-party employees) compared to 2023, the lowest in the last 5 years. Launch of the climate management tool - CBRAIN. Over 430,000 hours of training in health and safety in 2024. SOCIAL AND DIVERSITY ✓ +75% female representation in the CSN Group, compared to 2020 (baseline year). ✓ A 35% increase in training hours compared to 2023. ✓ CSN Foundation receives the Racial Equality Seal from the São Paulo City Hall (PMSP). ✓ 100% of employees trained in Compliance. ✓ R$ 66 million invested in social responsibility. DAM MANAGEMENT ✓ DCEs renewed in September 2024, with all dams considered stable. ✓ Completion of the decommissioning works of the Taboquinha 2 dam at ERSA. ENVIRONMENTAL MANAGE A record in environmental investments : R$ 1.2 billion in 2024 (CAPEX + OPEX). -7% reduction in tCO2e emissions per ton of steel, compared to the baseline year of the target (2018). - 10% reduction in kgCO2e emissions per ton of ore, compared to the baseline year of the target (2020). -3% reduction in kgCO2e emissions per ton of cementitious material, compared to the baseline year of the target (2020). - 23% reduction in water intake intensity per ton of ore produced , compared to 2023. CSN Cimentos wins 1st place in the Development category of the Ser Humano Award by ABRH-SP, with the Industrial Academy. CSN Foundation receives the Racial Equality Seal and joins of the municipal network for racial diversity in the labor market . TLSA celebrates receiving the ANTT 2024 Highlights Award in the Environmental Sustainability category. CSN Mineração wins four awards at the "O Grande Encontro 2024" event by the Brazilian Union of Quality (UBQ). AWARDS AND RECOGNITIONS CSN receives an award at InterZAC for reaching 5 million tons of Galvalume® produced Prada Uberlândia wins an award from the P4E Program, where all strategic suppliers of Danone compete . CSN Mineração ranked third in the "Steel, Mining, and Metallurgy" category at the 51st edition of the EXAME Melhores & Maiores award. 2024 CSN Cimentos was ranked by the global consultancy Great Place to Work among the 20 best companies to work for in the state of Rio de Janeiro. Main ESG Goals¹ ESG goals Climate Change ✓ 20% reduction in CO2e emissions per ton of crude steel by 2035, WSA² methodology compared to the base year 2018 ✓ Reduce CO2e emissions per ton of cement by 23% by 2030, reaching 392 kgCO2e/t cement, GCCA³ methodology compared to the base year 2020 Natural ✓ 30% reduction in CO2e emissions per ton of ore produced by 2035 (scopes 1 and 2), base year 2020. Capital ✓ Carbon neutral by 2044 in scope 1 and 2 emissions by CSN Mineração. Atmospheric Emissions Reduce 40% of particulate matter emissions per ton of crude steel produced at the UPV (steelworks) by 2030, base year 2019. Water Use Efficiency and Effluent Management By 2025, systematize and transparently present the volumes of water permitted, captured and released from CSN Group units, relating them to the risks of water scarcity in the basins in which they are located. Management and De-characterization of Dams Carry out the complete de-characterization of dams built upstream of CSN by 2030. Biodiversity Seek to achieve no net loss in biodiversity and, whenever possible, net positive impact (net gain). Intelectual Capital Human and Social Capital ESG goals Governance, Ethic and Compliance Maintain 100% of active employees trained in compliance, covering the code of conduct and anti-corruption policy. Continuously increase our Compliance Index with the best governance practices provided for in CVM Resolution No. 80/2022 (considered "Practice" and "Partially Practice"). Occupational Health and Safety Continually achieve the zero-fatality rate across the CSN Group (own employees and third parties). Reduce the accident frequency rate (LTI+NoLTI -