Evidence for the presence of dust in intervening QSO absorbers from the   Sloan Digital Sky Survey
  We find evidence for dust in the intervening QSO absorbers from the spectra of QSOs in the Sloan Digital Sky Survey Data Release 1. No evidence is found for the 2175 A feature which is present in the Milky Way dust extinction curve. The extinction curve resembles the SMC extinction curve. The observed Delta(g-i) excess for QSOs with strong absorption systems appears to be a result of the reddening due to dust in the intervening absorbers. 
P. Khare, D. G. York, D. Vanden Berk, V. P. Kulkarni, A. P. S.Crotts,   D. E. Welty, J. T. Lauroesch, G. T. Richards, Y. Als...