This is a multi-centered, placebo controlled and randomized clinical study designed to evaluate the therapeutic potential of CO2 enriched water on the treatment of distal extremity (foot) ulcers in patients with critical limb ischemia undergoing hemodialysis. Study participants will be patients receiving dialysis at two local hospitals in Winnipeg and will have been diagnosed with CLI and foot ulceration. Patients will be randomized to receive either treatment with CO2-enriched tap water, 1,000-1200 ppm CO2 (TREATMENT GROUP), or non-enriched tap water (CONTROL GROUP), bath therapy at 37ºC on the same day as dialysis (typically 3 times/wk), for 15 min for 4 months,. Blood (approximately 20 ml) will also be collected at baseline and at the end of every month of the treatment period (for a total of 5 collections) for the measurement of the different biomarkers.