Although it is well known that both benign and malignant pleural disorders can result from exposure to asbestos fibers, few other epidemiologic studies concerning the effects of NOA have studied both MM and PPs. The present study shows remarkably similar associations for MM and PPs, thus confirming that both conditions must be caused by a similar exposure. However, this similarity and the fact that we had about the same numbers of cases with MM and PPs do not mean that the two conditions occur with the same incidence. It is well known that PPs occur much more frequently than MM in asbestos-exposed populations.26,27 The fact that our study comprised similar numbers of patients with MM and PPs is unlikely to be due to misdiagnosis. In most of the patients with MM, the diagnosis of MM was confirmed by histology. We repeated the analyses including only the 79 patients with MM for whom a detailed pathologic report was available and found similar results, in that the ORs were slightly decreased in both sexes, but the statistical significance still held. PPs were diagnosed by chest radiograph or CT scan and not by thoracoscopy, surgery, or autopsy, but here, too, we may assume that most of these subjects really had PPs, because only those patients for whom the diagnosis had been made by a pulmonologist were included in the analysis. We presume that only patients with the most obvious radiologic presentations of PPs were included, because physicians tend not to register the presence of such lesions with little or no clinical relevance, in contrast to malignant diseases, which must be declared in Turkey. A related plausible explanation for the relatively low number of subjects with PPs in our study is that pleural lesions are generally asymptomatic and, hence, they do not lead one to seek medical treatment. Effectively, when systematically searched for by chest radiograph among 7,000 individuals around the town of Cermik in southeast Turkey, pleural thickening and calcifications were disclosed in 6.5%.28 On a more local scale, 18% of 124 individuals older than 20 years from an Anatolian village had PPs at chest radiograph.29 The source of the NOA fibers undoubtedly consists of the abundant ophiolitic structures containing chrysotile and tremolite fibers. The most relevant human exposure probably occurs through the use of this material to plaster walls inside and outside homes (Fig 2). Traditionally, in rural areas of Anatolia, people plaster the walls of their houses with some locally obtained material. In areas within, or close to, ophiolites, villagers like to use soils containing fibers, called “çorak” (in English, barren soil), which they claim have thermal insulation properties. In addition to such use of plaster, fiber exposure may occur during farming on contaminated land and as a result of the continuous resuspension of fibers with the wind or traffic on unpaved roads.