An unusual fungal infection outbreak at a paper mill in the U.S. state of Michigan, which infected more than 90 employees as of Friday, forced the factory to be closed for up to three weeks. Billerud, a Swedish pulp and paper manufacturer who owns the factory located in the city of Escanaba, announced Thursday night that the shutdown is a precaution to try and prevent any additional blastomycosis exposures. According to Billerud, the company was first notified about possible blastomycosis infections on March 3. The local health department for Delta and Menominee Counties was notified by a local hospital that they had found several atypical pneumonia infections, all from people affiliated with the mill. Follow-up testing, which took a couple of weeks, confirmed that some of the infections were caused by blastomycosis, a type of fungus that grows in moist soil and decomposing matter. The U.S. Centers for Disease Control and Prevention (CDC) indicated that once blastomycosis went inside a patient’s lung, the body’s warmth and moisture can transform the spores into yeast that can stay in the lungs or be transferred through the bloodstream to other parts of the body, including the skin, bones, joints, organs, brain and spinal cord.