Hydrogen sulfide (H2S) is a potentially hazardous gas that has been shown to reach elevated levels in swine barns, thus potentially posing a threat to the health and safety of workers and animals. Saskatchewan Labour (1996) stipulates that worker exposure to H2S should not exceed an 8 h time-weighted average of 10 ppm, or a 15 min TWA of 15 ppm. The immediately dangerous to health and life level for H2S is 100 ppm; at this level, olfactory detection is generally desensitized; thus, an exposed individual may not be able to distinguish higher concentrations based on intensity of smell alone. Chénard et al. (2003) found that swine barn workers were at risk of H2S exposure while performing manure management tasks that result in manure agitation, such as pulling pit-drain plugs to clear manure out of under-floor manure channels in swine production rooms. Hydrogen sulfide gas is created by anaerobic degradation of manure (Arogo et al., 2000). Long storage times of manure inside barns can contribute to the anaerobic degradation process, and consequently, to increased risk of generating potentially hazardous levels of H2S when manure is agitated during clear out. A potential method to reduce the production and eventual release of H2S and other manure gases is to remove the manure from the room on a more frequent basis. Voermans and van Poppel (1993) studied six scraper systems designed for swine barns, with and without separate discharge for urine, and found an overall reduction in ammonia (NH3) emissions. Therefore, the main goal of this study was to evaluate the effectiveness of daily operation of a manure scraper system for reducing the risk of H2S exposure of swine barn workers and animals during in-barn manure handling activities. The effectiveness of a manure scraper system for reducing the risk of barn worker and animal exposure to hydrogen sulfide (H2S) was evaluated by comparing gas levels in two swine production rooms, one with a manure scraper system installed (scraper) and the other with a conventional manure pit-plug system (control). Measurements were done over four production cycles; during each 12-week cycle, gas concentrations were measured 4 to 5 times during weeks that conventional manure removal activities were performed in the control room, while the scraper system was operated daily in the scraper room. Daily removal of manure from the scraper room resulted in measured maximum H2S concentrations that were significantly lower (by 90%) compared to the control room. The type of manure removal system had no significant effect on ammonia (NH3) concentration and emission; during each trial, NH3 emission increased in both rooms over the 4 to 5 monitored weeks. The scraper system was also operated in two different modes. These tests revealed that NH3 production was reduced when all the manure was removed from the room compared to leaving the liquid portion on the pit floor surface, although the differences were not significant. The estimated cost of including the scraper system in the construction and operation of a new barn is CDN$1.89 per pig sold, which is 35% less (on a per pig basis) than the cost of retrofitting an existing facility. The manure removal system tested was effective in reducing exposure of workers and animals to H2S, without significant adverse impact on NH3 production. However, given the highly variable nature of H2S production and dispersion within a room, care should always be taken when handling manure inside swine barns.