In a letter published Thursday in The New England Journal of Medicine, Dr. Michael A. Sue of the Southern California Permanente Medical Group in Panorama City, California, describes the case of a 37-year-old special-effects coordinator who attended an allergy clinic complaining of chronic cough and a runny nose.

The patient had tried a variety of treatments, including nasal sprays, cough suppressants, antibiotics, steroids, and surgery on his nasal septum.

On questioning the patient, Sue learned that he had recently worked for two days on a film set where artificial snow was in use. Film snow, Dr. Sue writes, is composed of polyethylene fibers, and the patient remembered inhaling some of these fibers.

Using bronchoscopy, a procedure where a flexible, lighted tube is inserted into the airways, Sue found white plaques in the man's lungs. During the procedure, the lining of the patient's airways were washed with fluid to obtain samples. Laboratory analysis of these samples showed "polyethylene fibers of the type composing the artificial snow"
Dr.  Sue notes that the man's cough improved after the bronchial washing.
The physician concludes, "all those in the moviemaking business are reminded: don't inhale the snow."