ASTM G175 is a standard test method for evaluating the ignition sensitivity and fault tolerance of oxygen regulators used for medical and emergency applications. During its development, interlaboratory testing was conducted to assess whether the standard could be performed reproducibly and repeatably. Specifically, this testing examined ignition pill production and the performance of different test systems using test articles manufactured specifically for this testing. Five laboratories used materials provided from single batch lots to manufacture ignition pills, and their heat of combustion was determined and compared to G175 requirements. To determine whether the performance of different test systems would affect upcoming interlaboratory testing, four laboratories tested CGA 870-style test articles manufactured to examine the flame jet resulting from pill ignition. Still photography was used to capture the ignition events; these photos were used to compare test system performance. This paper discusses these results in relation to the repeatability and reproducibility of G175 and the possible effect on future interlaboratory testing, which will involve actual off-the-shelf regulators.