Fit testing of tight-fitting respiratory protective facepieces has been in use for some years, but there are still widespread misconceptions and misunderstandings about what a fit test pass actually signifies. Various aspects frequently generate research papers, and there are three relevant ones in this issue (Han and Lee, 2005; Kuo et al., 2005; Vaughan and RajanSithamparanadarajah, 2005). In ...