State documents show emissions from Foxconn Technology Group's planned manufacturing complex would rank among the highest in southeastern Wisconsin for toxins that create air pollution known as smog.
The Milwaukee Journal Sentinel reports that documents filed with the state Department of Natural Resources indicate that Foxconn's most significant air pollutants would be volatile organic compounds and nitrogen oxides.
The state's air management staff say the factory would increase such pollutants by about 4 percent in Racine County, a figure officials say is manageable.
The DNR is reviewing Foxconn's permits and says it will likely require additional emissions cuts on top of what the company is proposing.
Smog can be a health risk and harm the lungs for people working and exercising outdoors.
The $10 billion plant could employ up to 13,000 and will manufacture advanced liquid crystal display panels.