Ozinga Opens 1 Million Ton Slag Cement Mill in East Chicago to Expand Low-Carbon Concrete Supply

Ozinga opened a slag cement mill in East Chicago, Indiana, on October 13, 2026, adding 1 million tons of annual capacity. The company calls it the largest mill of its kind in North America. Slag cement uses a processed ironmaking byproduct to replace part of the Portland cement in concrete, which cuts embodied carbon because it avoids some clinker production. Ozinga says certain CarbonSense blends can reduce embodied carbon by up to 80% compared with traditional mixes and that full operation could avoid more than 700,000 metric tons of CO2 per year, though those figures have not been independently verified at the new plant. The mill is positioned for rail, barge, and highway distribution from East Chicago, with slag supplied by Ozinga's Burns Harbor operation at a Cleveland-Cliffs steel site. That helps regional ready-mix producers diversify supply, but delivered prices, curing behavior, and long-term slag availability will determine how much low-carbon cement actually gets used. Contractors subject to embodied-carbon limits should watch for verified EPDs and performance data before specifying high-slag mixes.