Artisanal fishermen in the Yucatán dive frequently to capture fish for sustenance, and some of their techniques involve breathing compressed air while underwater. Decompression Illness (DCI) has become endemic among the fishermen, and is caused by the formation of inert gas in the body, such as the bubbling you see in carbonated drinks. With previous data collection and analyses, we identified a proper decompression stop, and now want to implement it among 150 fishermen to see if it reduces DCI.