Optical Gas Imaging (OGI) is an important next generation emission measurement (NGEM) technique for finding fugitive industrial emissions (leaks) of methane and volatile organic compounds. The ability of OGI to detect leaks depends on many factors including the skill and training of the OGI operator. This dataset was produced at the Colorado State University Methane Emissions Test and Evaluation Center (METEC) where simulated leaks of various sizes from oil and gas production equipment could be generated. Dozens of OGI operators from different organizations with various levels of experience participated in a test series to establish their ability to detect leaks under varying conditions using the protocols and procedures they normally employ. This dataset contains the results from this test series. The associated journal article advances understanding of OGI methods and training using these data. This dataset is associated with the following publication: Zimmerle, D., T. Vaughn, C. Bell, K. Bennett, E. Thoma, J. Dewees, and P. Deshmukh. Detection Limits of Optical Gas Imaging for Natural Gas Leak Detection in Realistic Controlled Conditions August 2020. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY. American Chemical Society, Washington, DC, USA, 54: 18, (2020).