Swine producers are exposed to dusts and gases when working in barns. Studies have shown that these workers are at increased risk of developing respiratory symptoms, decreases in lung function levels and increases in airway reactions. Compared to no dust control, canola oil sprinkling can significantly reduce dust levels and resulted in lower health effects on healthy subjects when exposed to this environment (Senthilselvan et al. 1997). While engineering controls are in development in an attempt to reduce the dust and gas levels in this work environment, one method for reducing worker exposure to dusts is by having workers wear a disposable respirator (N-95 mask) during barn work activities. The objective of the study was to evaluate health effects related to wearing a disposable mask in a swine confinement unit. Twenty-one subjects between the ages of 18 and 35 years old were recruited to participate in the study. These subjects were male and pre-screening insured that all subjects were non-smokers, with no asthma or allergies and that they had no previous exposure to a swine barn environment. The subjectsa