This study investigates the potential of waste utilization to mitigate greenhouse gas (GHG) emissions within the steel manufacturing industry. Utilizing a translog production function, we analyze the substitution elasticities among scrap steel, iron ore, and energy, exploring their roles in carbon reduction. Our approach incorporates the Resource Efficiency and Climate Change Mitigation model to simulate the impact of various waste utilization strategies on GHG emissions. The findings highlight that scrap steel and iron ore exhibit substitution dynamics. Iron ore and energy exhibit complementary relationship, and there is also a complementary relationship between scrap steel and energy but with lower elasticity, indicating that increasing scrap steel usage can significantly reduce emissions while decreasing iron ore demand. Specifically, enhancing the input efficiency of scrap steel in secondary steel production can reduce GHG emissions by over 8.3 tons for each additional ton produced—surpassing the impact of merely increasing the volume of reused material, which offers a reduction of more than 2.2 tons per ton. The strategies centered on reduction and recycling demonstrate even lower GHG reduction efficiency. The findings advocate for governmental intervention to promote and support waste reuse initiatives, highlighting the potential environmental benefits and efficiency gains from such policies.