Carcinogenic emissions and lead pollution Burns Harbors was named "largest source of industrial lead pollution" in the United states by the Chicago Tribune after its blast furnaces emitted nearly 18,000 pounds of lead and 173,000 pounds of cancer-causing benzene in 2016. Additionally in 2021, the plant was responsible for 11,046 tons of asthma-causing sulphur dioxide, making it the largest emitter in Indiana. Burns Harbor is also home to two coking plants, which process metallurgical coal into coke, which can be burned in a blast furnace. According to a peer-reviewed public health study conducted on a similarly sized steel plant also on Lake Michigan, closing a coking plant can reduce weekly emergency room visits for cardiovascular admissions by 42%. 

Colossal and unnecessary carbon emissions According to estimates derived from the US Environmental Protection Agency’s Greenhouse Gases data set, If just one blast furnace at Burns Harbor is relined, it would release an estimated 68 million tonnes of CO2e over its extended lifetime, equivalent to operating a coal plant every year for 18 years. In order to be in line with limiting global warming to 1.5C, blast furnaces that reach the end of their lifetimes in this decade must be transitioned to fossil free technologies. 

False climate solutions In December 2022, Cleveland-Cliffs proposed a carbon capture and storage (CCS) project on one of its blast furnaces at the Burns Harbor plant. It is currently planning the pilot, with a planned completion date of end 2023. The goal of the pilot is to capture at least 95% of CO2 released from the blast furnace. However, there have been no successful CCS projects in steel making to date, and it has not proven successful in other fossil-fuel based sectors. Additionally, CCS does not address the methane released from coal mining, which would still be required if the blast furnace continues to be used. Therefore, instead of relining the coal-based production facilities at Burns Harbor in combination with currently unproven CCS technology, Cleveland-Cliffs should use the current opportunity to shift the plant to fossil free production technologies.

Acidification of Lake Michigan Due to a failure in the blast furnace water recycling system, in August 2019 Burns Harbor discharged millions of gallons of water containing cyanide and ammonia-nitrogen into the Little Calumet River and Lake Michigan. As a result, an estimated 3,000 fish died, beaches in the Indiana Dunes National Park were closed, and contaminated the drinking water of local communities. The Environmental Law and Policy Center  found that Burns Harbor had violated the Clean Water Act over 100 times between 2015-2019.