Transient hazards to human and animal health can occur in swine barns due to sudden bursts of high concentration hydrogen sulfide (H2S) gas released when manure slurry is agitated during removal from sub-floor pits. Studies have shown that H2S levels can go from harmless to deadly in a matter of minutes during pit agitation (Patni and Clarke, 2003). From 1983 to 1990, H2S poisoning was responsible for the death of 24 swine workers in the Midwest alone and at least 15 more deaths since 1994 (Walinga, 2004). Swine slurry removal workers and producers report swine deaths every year from slurry agitation in sub-floor storage, or pits. Hence, a system that can reliably and promptly report H2S concentrations in swine housing without direct exposure of the operator(s) to the potentially hazardous environment is of socioeconomic importance to the swine producers. This paper describes the development and testing of a wireless, portable H2S detection system, followed by the use of the system under field conditions by slurry removal workers to monitor H2S levels during slurry agitation and removal in deep-pit swine housing systems in Iowa. The system developed in this study has a component cost of $2,735 and is based on a Pemtech PT-295 electro-chemical H2S sensor and a Phoenix Contact Wireless Transmitter / Receiver set. The portable H2S detection system has the following operational characteristics: a) 90% (t90) response to 10 - 500 ppm H2S within one minute, b) ± 5 % full scale accuracy, and c) < 2 hr warm-up time for operation.