ESCANABA, Mich. (Michigan News Source) –Health officials in the Upper Peninsula are investigating an outbreak of a rare fungal disease among workers at an Escanaba paper mill.

Late last month, Public Health Delta and Menominee Counties (PHDM) received word of several atypical pneumonia infections in people who worked at the Billerud Paper Mill.

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Since then, officials have identified 35 confirmed or probable cases of Blastomycosis among mill workers. According to the U.S. Centers for Disease Control and Prevention, the fungus that causes Blastomycosis grows in moist soil and decomposing matter. People can get sick from breathing in spores, but the disease does not spread from person to person.

According to Billerud Operations Vice President Brian Peterson, there has been no causal link between the fungus and the mill, but the company has taken proactive steps. In addition, Peterson said the health and safety of Escanaba employees is a top priority.

Officials said the fungus is common in the U.P. environment, but have not determined the source of the fungus in this case.