for adequate inhalation protection against cotton dust.[1] That is, certain "maintenance-free" halfmasks with filtering facepieces for which it is "difficult, if not impossible, for the wearer to cover the entire [filtering] surface area, but not the seal be- tween the respirator and the wearer's face"[2] during the user fit check recommended by the manufacturer. The federal court stated that: OSHA recognized that, in the case of [certain filtering-facepiece] disposable respirators, the wor- ker's hands cannot effectively block intended air intake, and that intake only, while leaving unob- structed air taken in because of the respirator's improper fit. The federal court also noted that: 22 Absent assurance of a respirator's proper fit, the NIOSH and ANSI ratings can reliably indicate only the efficiency of the filter, not the effectiveness of the entire respirator as it is used on the job. 23 Therefore, filter mask purchasers and users must recognize that indispensable as they are, reliable and effective fit testing and fit checks cannot detect excessive filter leakage. The 1987 NIOSH-recommended APFS for dust, fume, and mist (DFM) filter respi- ▲ rators certified under 30 CFR Part 11 were determined by a process that did not fully embody the fundamental strategy underlying the performance tests and APFs recommended in this evaluation and did not fully recognize the potential protection defects for certain filter types. Therefore, NIOSH decided to reexamine the basic as- sumptions underlying the Institute's 1987 APF recommendations for both air-puri- fying and atmosphere-supplying respirators. 22Tbid., 23Tbid., p. 492.
p. 493.
