This research was aimed at testing a hypothesis,that at elevated CO2 pressure coal can soften at temperatures well below those obtained in the presence of other gases.That could have serious negative implications for injection of CO2 into deep coal seams.We have examined the experimental design issues and procedures used in the previously published studies,and experimentally investigated the physical behavior of a similar coal in the presence of CO2 as a function of pressure and temperature,using the same high-pressure micro-dilatometer refurbished and carefully calibrated for this purpose.No notable reduction in coal softening temperature was observed in this study.