Workplace Medical Mystery Solved: Unknown Illness in Worker at Greeting Card Plant

Posted on by Emily Kirby, BPH; Rachel Bailey, DO, MPH; Lew Radonovich, MD

Medical Mystery logoCamilla started experiencing worsening respiratory symptoms while working at a plant that produces greeting cards. (Read about her symptoms here). Her doctor ordered tests to see what was happening with Camilla’s lungs. The results of two lung function tests showed concerning results. One was a carbon monoxide diffusing capacity test that estimates the ability of the lung to transfer oxygen from the air to the person’s bloodstream. The other was a spirometry test which measures the ability to move air in and out of the lungs. Camilla’s tests showed that her lungs had diminished function compared to other people with healthy lungs. Tests also showed scarring and stiffness of the lung tissue. Knowing Camilla worked at the plant, Dr. Gallagher thought Camilla was suffering from a disease called flock workers’ lung.

Flock workers’ lung is a form of interstitial lung disease sometimes seen among workers exposed to flock dust. Interstitial lung disease involves inflammation of the lung’s air sacs and airways and scarring of tissue that causes the lungs to become stiff, small, and less effective at transferring oxygen into the blood and carbon dioxide out from the blood. Flock consists of short fibers that are cut from long filaments (e.g., nylon, rayon, acrylic, polyester). The fibers are glued to material for decorative and functional purposes like noise reduction, friction modification, and surface protection. Camilla notified her plant’s occupational safety and health professional, who requested an investigation from NIOSH.

An environmental and medical survey at the plant found that working with flock and cleaning with compressed air were associated with health effects in workers at the plant. Following the investigation, NIOSH recommended changes to help the plant leadership reduce workers’ exposures to flock:

  • Prevent dust exposures with engineering controls and improved work practices
  • Improve local exhaust ventilation at the flock lines, especially at flock feed and discharge points
  • Provide local exhaust ventilation for the dust generated by the compressed air that separates flocked cards
  • Provide cleaning methods that reduce the need to reach into the flock machines to remove any residue from the conveyor lines
  • Use vacuums equipped with high-efficiency particulate air filters instead of compressed air, when possible, for cleaning or removing dust from workers’ clothing
  • Conduct air sampling regularly to monitor effectiveness of controls
  • Use respirators until effective engineering controls and work practices are in place
  • Require workers to wear NIOSH Approved® respirators with particulate filters during tasks with potential for exposure to flock like when bagging flock, loading flock machines, or using compressed air
  • Ensure respirators are used in conjunction with an OSHA-compliant Respiratory Protection Program (29 CFR 1910.134) that includes medical evaluation, training, and fit testing (Some states may have applicable federal OSHA-approved state plans)
  • Educate workers about work-related disease observed among flock workers and how to reduce or control their risk
  • Train workers on potential work hazards, like flock dust, and associated safe practices, procedures, and protective measures
  • Encourage workers to seek medical evaluation for respiratory symptoms, like shortness of breath, wheezing, or phlegm production and inform their health care providers of flock exposures
  • Implement a smoking cessation program to help employees stop smoking
  • Preventing smoking-related lung disease is important and makes it easier to detect work-related adverse effects

After the investigation, Camilla completed a medical evaluation and then was fit tested for a respirator that she wears during her shift. She also stopped using compressed air to remove dust from her clothes and instead used a new vacuum provided by the plant. Combined with the engineering controls the plant is implementing, these actions should help prevent further exposure to flock dust.

For More Information:

Health Hazard Evaluation: Hallmark Cards, Inc. Lawrence, Kansas January 2006

Health Hazard Evaluation: Claremont Flock Corporation Leominster, Massachusetts August 2006

Types of Respiratory Protection

Fit Test FAQs 


Emily Kirby, BPH, is a Health Communication Specialist in the NIOSH Office of Communication and Research to Practice.

Rachel Bailey, DO, MPH, is a Medical Officer in the NIOSH Respiratory Health Division.

Lew Radonovich, MD, is the Deputy Director in the NIOSH Respiratory Health Division.


Workplace Medical Mysteries are fictional; however, they are loosely based on Health Hazard Evaluations (HHEs) conducted by NIOSH or other reports by NIOSH. Any recommendations made were for the specific facility evaluated and may not be universally applicable and are not to be considered as final statements of NIOSH policy or of any agency or individual involved. HHEs are publicly available at, but the names of individuals and facilities mentioned in this series have been changed to protect their identities. For more information on the NIOSH HHE program, visit

Posted on by Emily Kirby, BPH; Rachel Bailey, DO, MPH; Lew Radonovich, MD

One comment on “Workplace Medical Mystery Solved: Unknown Illness in Worker at Greeting Card Plant”

Comments listed below are posted by individuals not associated with CDC, unless otherwise stated. These comments do not represent the official views of CDC, and CDC does not guarantee that any information posted by individuals on this site is correct, and disclaims any liability for any loss or damage resulting from reliance on any such information. Read more about our comment policy ».

    It’s heartening to see that there are dedicated professionals like yourselves working to solve these medical mysteries and improve patient outcomes.

    I’m also impressed by the multidisciplinary approach that your team took, bringing together experts from different fields to collaborate on this case. This is a great example of how teamwork and communication can lead to better patient care and outcomes.

    Overall, I found this blog post to be a fascinating read and a testament to the importance of ongoing research and investigation in the medical field. Thank you for sharing this case with us and for the important work that you do.

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Page last reviewed: April 7, 2023
Page last updated: April 7, 2023