In oxygen-deficient or toxic environments in which controlling the hazard is not feasible, workers wear personal protective respirators. Hazard controls include but are not limited to engineering controls, such as ventilation, and substituting less hazardous materials. However, respirator selection and the design of tasks that require respirators are critical issues. Understanding the effects of respirators on human abilities is critical to respirator selection and therefore to the safety and efficiency of workers. This research investigated the effect of respirators on human abilities. A review of the relevant literature was conducted, revealing that respirators can affect physiological, psychological, motor, and visual abilities. However, the effect varies with different types of respirators, environments and task types and difficulty levels. The details of this variance were identified and further investigated through experimentation. The study compared a dust respirator, powered-air purifying respirator and full-facepiece respirator in terms of their effect on fine motor, visual and cognitive tasks. Thirty participants performed the Hand Tool Dexterity test, Motor-Free Visual Perception test (MVPT-3) and Serial Seven test. Each participant performed each task without a respirator and then while wearing each type of respirator. Task completion time and error rate were measured as indicators of performance. Participants also were surveyed regarding respirator comfort, anxiety level, and perceived task difficulty. ANOVA, least significant difference, and least square means analyses showed that none of the respirators significantly affected task completion time. A significant increase was found in the error rate when participants performed the cognitive test while wearing the full-facepiece respirator --Abstract, page iv
