Abstract This study aimed to assess remote sensing methods using open path laser technology as a tool for atmospheric monitoring of CO 2 storage sites. CH 4 and CO 2 open path detection systems were tested at the Penn West Pembina Cardium CO 2 enhanced oil recovery monitoring pilot. The tested CH 4 detection system was found to be very sensitive and small increases in the gas concentration due to controlled releases were easily distinguishable. The detection capability of the CO 2 detection system was impacted by the larger natural background concentration of CO 2. Where possible, CH 4 should be used as an indicator due to the better detection capabilities and smaller background concentration variations compared to CO 2.