Pollution from domestic steel mills accounts for about 15 percent of carbon emissions in the United States. But the steel industry is trying to reduce its carbon footprint. Companies are testing prototypes of systems that could enable manufacturing steel without the use of fossil fuels that have detrimental environmental impacts. Experts say this will require big changes in how steel is now made. Each potential solution faces challenges in terms of costs and the availability of key resources, says Professor Sridhar Seetharaman, the Fulton Schools vice dean for research and innovation, whose expertise is in materials science and engineering. Seetharaman says a mix of different methods will likely be needed to achieve major carbon emissions reductions.