For context, that seems to make coal ash about as radioactive as granite based on these figures for the latter: https://www.sciencedirect.com/science/article/pi

For context, that seems to make coal ash about as radioactive as granite based on these figures for the latter: https://www.sciencedirect.com/science/article/pii/S1687850717300870 https://www.sciencedirect.com/science/article/pii/S168785071...