Kern's occupational medicine unit in Providence, Rhode Island, led the investigation that defined flock worker's lung, although the National Institute for Occupational Safety and Health (NIOSH) was also involved. As the pattern of the disease emerged-most strikingly, an incidence at least 50 times that of interstitial lung disease in the general population-even career scientists at NIOSH, accustomed to seeing strange and disturbing things in their line of work, sat up and took notice. Commenting on flock worker's lung, Jack Parker, chief of NIOSH's examination processing branch, put it this way [5]: "In the world of occupational lung disease, this is a big deal."

The paper by Kern and colleagues is interesting in itself for a variety of reasons. First, it raises the possibility that nylon fiber, previously thought to be biologically inert, may under certain circumstances elicit a vigorous pathologic inflammatory response. However, more than nylon fibers may be involved here because, in the words of the NIOSH report [6], the data give "reason to be concerned about the potential respiratory toxicity of both the nylon fragments themselves and the flock finish they carry, not to mention the endotoxin contamination that may also be present." We clearly still have a lot to learn about the pathophysiology of this reaction. Second, the number of workers at risk is substantial. As many as 2500 persons may be employed in the nylon flocking industry in the United States alone, and many thousands more work in the industry in other countries. At the same time, the study by Kern and colleagues suggests that the disease can largely be prevented by limiting occupational exposure to nylon fiber dust; recognition of this risk could therefore be important in protecting a substantial number of workers.

But the study by Kern and colleagues is also of interest for reasons that are not obvious from the paper itself. The interest lies in the story of how the investigation of this new disease was severely buffeted in a sea of strong, conflicting interests. It is a story of politics, economics, and ethics rather than biology. The parties involved included Kern's academic occupational medicine unit, the teaching hospital in which the unit was based, the department of medicine and the university with which the unit was connected, the manufacturing company and its exposed workforce, a labor union, and NIOSH. The bare facts of the case include efforts by both the company and the medical school to prevent Kern's group from presenting their initial findings at a major scientific meeting; the presentation of a "watered down" version of the paper at that meeting [2]; a major letter writing campaign executed by professional colleagues and organizational statements in support of the right of Kern's group to make their findings publicly available; the subsequent elimination of Kern's occupational medicine unit by the hospital; a decision not to renew his employment contract; and, ultimately, an official action by Kern against the company, the hospital, and the university, claiming that his rights under the Occupational Safety and Health Act had been violated. As of this writing, the case has been forwarded for review to the Solicitor's Office of the U.S. Department of Labor.

Although investigations of occupational risk often run smoothly, the turbulent story of the flock worker's lung investigation is, unfortunately, an old one: Powerful competing interests rise quickly to the surface when occupational medicine researchers dig for facts in the world of commerce. As you might expect, the full story of the flock worker's lung investigation is enormously complicated and, as in the film Rashomon, views of the same events vary with the teller. Kern himself has recounted the story in detail [7], and numerous other accounts have appeared in scientific journals and the general press [8-19]. To provide further insight into what happened, we asked Miriam Schuchman, an experienced physician-journalist, to re-explore the story in depth; her findings appear in this issue [20].

Readers will have to decide for themselves what lessons to take away from this experience. At best, this is a story of incorrect assumptions and mutual misunderstandings by well-intentioned persons on all sides, starting early in the investigation and leading, over time, to a self-reinforcing downward spiral of further misunderstandings and deepening mistrust. At worst, it is a story of narrow self-interest getting in the way of public disclosure, responsibility to patients, and academic freedom. It is very likely that some elements of both were involved. But whatever else it proves to be, the story is a sobering reminder that the practice of medicine, even at its scientific best, is always a social act.