On April 21, 2022, researchers at the Centers for Disease Control and Prevention’s (CDC) National Institute for Occupational Safety and Health (NIOSH) and the Bacterial Special Pathogens Branch describes cases of welder’s anthrax, a newly identified, deadly occupational disease.

Welder’s anthrax is defined as pneumonia in a metalworker caused by bacteria within the B. cereus group that produces anthrax toxin. Seven patients diagnosed with what is now termed welder’s anthrax were reported to the CDC from 1994–2020. The job title of six patients was welder, and the job title of the seventh was metalworker. All were confirmed to be infected with B. cereus group bacteria containing anthrax toxin genes. Six of the workers were men. The median age was 39 years. Four of the patients worked in Texas and three in Louisiana.

Information on the type of welding, job activities, and type of workplace, including indoor or outdoor activities, was limited for most of the patients except for the two patients diagnosed in 2020. One patient worked on the roof of an oil tank outdoors. He welded on new A36 mild carbon steel using a shielded metal arc welding (or stick) process. The other patient worked in a wood fabrication shop. He welded on low-carbon mild steel using Metal Inert Gas (MIG) with solid or flux core wire and 75% argon/25% carbon dioxide shield gas. Both patients performed additional tasks such as scrubbing debris with a wire metal brush and grinding. Both reportedly wore respiratory protection during welding activities.

Of the six patients with available data on signs and symptoms, over half presented with each of the following: fever or chills, cough, shortness of breath (dyspnea), and coughing up blood (hemoptysis). All had abnormal chest radiographs and were diagnosed with pneumonia. All were hospitalized and were admitted to the intensive care unit if they survived past the emergency department. Five of the seven patients died. All patients received broad-spectrum antibiotic treatment. One of the surviving patients received raxibacumab, a monoclonal anthrax antitoxin.

Physicians should consider welder’s anthrax in welders who present with pneumonia, particularly those working in U.S. Gulf Coast states. Welders and other metalworkers who present with welder’s anthrax should be treated the same as a patient with inhalation anthrax.

If infection with anthrax toxin-expressing B. cereus group is suspected, it is important to notify the state health department; a consultation with CDC is recommended. Anthrax antitoxins should be considered as adjunctive therapy if the patient’s clinical condition suggests systemic illness. However, the role of anthrax vaccine pre- or post-exposure for welders is not currently recognized or understood.

Communication and cooperation between clinicians, employers, and public health practitioners is important to identify cases of welder’s anthrax and occupational and personal risk factors. More research is needed to better understand the mechanisms of infection and disease among welders. Additional research is needed to better understand how exposure to metal fumes and other welding hazards may increase susceptibility to and severity of lung infection in welders. The effectiveness of interventions to minimize workers’ exposure to metal fumes, including engineering controls and respiratory protection, should also be explored.