  We present a new dust extension to the Monte Carlo radiative transfer code
crash, which enables it to simulate the propagation of ionizing radiation
through mixtures of gas and dust. The new code is applied to study the impact
of dust absorption on idealized galactic H II regions and on small scale
reionization. We find that H II regions are reduced in size by the presence of
dust, while their inner temperature and ionization structure remain largely
unaffected. In the small scale reionization simulation, dust hardens ionization
fronts and delays the overlap of ionized bubbles. This effect is found to
depend only weakly on the assumed abundance of dust in underdense regions.
