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Flock worker's lung

David G Kern, MD
Robert S Crausman, MD
Section Editor
Talmadge E King, Jr, MD
Deputy Editor
Helen Hollingsworth, MD


An outbreak of work-related interstitial lung disease among employees at a Rhode Island textile plant specializing in the manufacture and application of nylon flock was described in 1998 [1,2]. Based on a case definition of persistent respiratory symptoms, previous work in the flocking industry, and histologic evidence of otherwise unexplained interstitial lung disease, a cluster of eight cases of flock worker's lung was recognized among fewer than 200 at-risk workers at a single production facility [1]. More than two dozen cases have now been reported among nylon flock workers in Rhode Island, Massachusetts, North Carolina, and Ontario [1,3-5].

The epidemiology, clinical features, and natural history of flock worker's lung are described here. General issues related to the diagnosis of interstitial lung disease are discussed separately. (See "Approach to the adult with interstitial lung disease: Clinical evaluation" and "Approach to the adult with interstitial lung disease: Diagnostic testing".)


In the flocking industry, short fibers (flock) are cut from cables of synthetic monofilaments and applied to adhesive coated fabric surfaces to produce velvet-like materials often used to produce upholstery, blankets, and clothing [1,3,4]. Exposures common to the nylon flocking industry include nylon, tannic acid, acrylic adhesive, nonfibrous zeolite, heat transfer oil, thermal degradation products, and ammonium ether of potato starch [1].

Although most nylon flock manufacturers worldwide use guillotines to cut flock, two large North American companies use rotary cutters. The rotary cutters apparently generate substantial quantities of respirable-sized nylon particles [4,6]. Inhalation of these fibers resulted in pulmonary toxicity in one animal model; however, these findings were not replicated in a separate industry-sponsored experiment [7,8]. All affected nylon flock workers described thus far have had occupational exposure to rotary-cut flock [4].

The polycationic nature of nylon flock is reminiscent of the polycationic compounds in Acramin-based spray paint, which caused occupational outbreaks of organizing pneumonia in Spain and Algeria, and the humidifier disinfectant polyhexamethylene guanidine, which caused an outbreak of interstitial lung disease in Korea [9]. Experimental studies in animals support the idea that the polycationic nature of these agents contributes to lung toxicity when the agents are inhaled despite apparent absence of toxicity in dermal and oral exposure studies.

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Literature review current through: Nov 2017. | This topic last updated: Nov 17, 2017.
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