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Rare fungus sickens dozens at UP paper mill. Unclear how they were exposed

mill in Escanaba, Michigan
At least one worker at Billerud’s Escanaba Mill was hospitalized for weeks with a rare fungal infection; others were able to continue working, said Gerald Kell, president of United Steel Workers Local 21, which he said represents about 670 of the 800-some workers at the plant. (Courtesy photo)
  • A fungus known to thrive in the Upper Peninsula, doesn’t usually make people sick 
  • But at least 90 paper mill workers have been infected, including some that have been hospitalized. There have been no deaths.
  • Zeroing in on the source is tough; symptoms don’t emerge until up to three months after exposure.

A fungal infection continues to spread among paper mill workers in an Upper Peninsula town, but zeroing in on the source will be difficult.

The fungus blastomyces often doesn’t affect those who are exposed, but for others, especially those with compromised immune systems, it can cause serious illness.

Several people have been hospitalized in the outbreak in Escanaba, while others have been able to continue work without interruption, said Gerald Kell, president of United Steel Workers Local 21, which he said represents the plant’s workers.


Because the fungus doesn’t spread from person to person, outbreaks are rare.

a bunch of people in a room with food
Members and supporters of United Steel Workers Local 21 in Escanaba held a fundraiser April 2 to support workers sickened by a rare fungal infection. (Courtesy of USW Local 12)

Federal health and occupational safety officials who visited the site March 27 and March 28 have advised Swedish owner Billerud to continue providing N95 masks for workers, curb unnecessary work outside the facility that could disturb the soil and scatter fungal spores, and keep doors closed as much as possible.

Another tour is scheduled for later this month, according to a follow-up letter dated April 7 to Billerud from a health scientist in the Respiratory Health Hazard Evaluation and Technical Assistance Program at the National Institute for Occupational Safety and Health.

At that time, employees will be offered urine tests to test for blastomyces and questionnaires. Those results, then, will guide soil sampling, according to the letter.

At least 93 people are confirmed or suspected of being infected with blastomycosis, which is caused by breathing the spores of the fungus blastomyces, according to Public Health Delta & Menominee Counties.

The fungus thrives in moist soil and in decomposing wood and foliage, and it generally does not make people sick. 

It’s known to live in areas around the Ohio River and the Great Lakes, among other places, according to the U.S. Centers for Disease Control and Prevention. Once the spores are inhaled, the host’s body temperature triggers them to transform into a budding yeast. That, in turn, can colonize the lungs and spread through the bloodstream to skin, bones and joints, organs, and the central nervous system, according to the CDC

Local health officials were notified Feb. 28 of what appeared to be “atypical pneumonia infections” among Billerud Mill employees.

Over the next six weeks, cases continued to mount. As of Friday, lab tests have confirmed infections in 19 people; another 74 workers have been classified as “probable” cases. 

Most people will not be sickened by the spores, but others can develop a fever and cough and more serious complications. Those in forestry work, hunting, and camping, and those with compromised immune systems, may be at higher risk for getting blastomycosis, according to the CDC.

For those who do get sick, symptoms include coughing — sometimes with blood as well fever, chest pain, difficulty breathing, night sweats, fatigue, weight loss, aches and pains.

Investigators who visited in March were accompanied by the Michigan Department of Health and Human Services, and they were invited by Billerud for a Health Hazard Evaluation, according to the follow-up letter by NIOSH.

The effort pulls together experts to determine the presence of worker hazards; however, its suggestions to address hazards are not binding.

Local health officer Mike Snyder said health officials are making no other comment, and he would only confirm to Bridge that there have been no deaths.

There is no vaccine, but prescription antifungal medications are especially effective when given as soon as symptoms appear.

Rare, source unknown

Blastomycosis is not contagious — it doesn’t spread from person-to-person, and it’s rare.

On average over the past ten years, an average of 22 cases have been reported for all of Michigan each year, according to the Michigan Department of Health and Human Services disease surveillance reports. The state’s Upper Peninsula “is a known risk area for blastomycosis infection,” according to the local health department

Local and state health officials are working with Billerud leaders, but identifying a precise source may prove difficult. 

“Whether or not we actually ever identify the specific source is up in the air,”  said Kell, the union president.

Blastomyces fungus is common in the woody environment in the UP and most people are not sickened when exposed. And even when a person is infected — he or she may not show symptoms for weeks or up to three months after exposure.  That means some workers may have been exposed late in 2022.

In fact, according to a statement from Billerud to Bridge, “there has never been an industrial outbreak of this nature documented anywhere in the U.S from which we can learn.”

The company said it has worked “proactively and diligently” with health officials. Echoing suggestions from officials who toured in March, the company said it has taken several steps to protect employees. It has retained an industrial hygienist and “conducted deep cleaning in high traffic areas throughout the mill, inspected ventilation systems and replaced filters, and tested various raw materials coming into the mill.”

The company is also providing N95 masks to all employees, contractors and visitors.

An uncertain future

The infection spread at a pivotal moment for the site, which has anchored the economy of the area for more than a century.

The mill, which opened in 1911, offered “good-paying jobs” and benefits, said Ed Legault, executive director for the Delta County Economic Development Alliance. “Several families …. have had three generations that have worked there, like a grandfather, father and son.”

Last year, Billerud acquired the mill when it bought out the mill’s owners at the time, Verso. Billerud now is considering a $1.2 billion retooling that would shift  production from paper to more lucrative packaging products, but the Michigan site is one of three options.

Legault at the economic development office said there’s no reason that the fungal infections outbreak — while it must be addressed and workers made safe — should derail the overhaul. The company is expected to announce its decision on whether to move forward with the expansion by early summer, he said.

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