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Hubble Space Telescope images of MCG-6-30-15 show a dust lane crossing thegalaxy just below the nucleus. In this paper, we argue that this dust lane isresponsible for the observed reddening of the nuclear emission and the Fe Iedge hinted at in the Chandra spectrum of MCG-6-30-15. We further suggest thatthe gas within the dust lane can comprise much of the low ionization component(i.e., the one contributing the O VII edge) of the observed warm absorber.Moreover, placing the warm absorbing material at such distances (hundreds ofpc) can account for the small outflow velocities of the low ionizationabsorption lines as well as the constancy of the O VIII edge. Photoionizationmodels of a dusty interstellar gas cloud (with a column appropriate for thereddening toward MCG-6-30-15) using a toy Seyfert 1 spectral energydistribution show that it is possible to obtain a significant O VII edge(\tau~0.2) if the material is ~150 pc from the ionizing source. ForMCG-6-30-15, such a distance is consistent with the observed dust lane. Thecurrent data on MCG-6-30-15 is unable to constrain the dust composition withinthe warm absorber. Astronomical silicate is a viable candidate, but there areindications of a very low O abundance in the dust, which is inconsistent with asilicate origin. If true, this may indicate that there were repeated cycles ofgrain destruction and growth from shocks in the interstellar medium ofMCG-6-30-15. Pure iron grains are an unlikely dust constituent due to the limiton their abundance in the Galaxy, yet they cannot be ruled out. The high columndensities inferred from the highly ionized zone of the warm absorber impliesthat this gas is dust-free.Comment: 7 pages, 3 Figures, A&A accepte

On the location and composition of the dust in the MCG–6-30-15 warm absorber