Limits on Intergalactic Dust During Reionization
  In this Letter, we constrain the dust-to-gas ratio in the intergalactic
medium (IGM) at high redshifts. We employ models for dust in the local Universe
to contrain the dust-to-gas ratio during the epoch of reionization at redshifts
z ~ 6-10. The observed level of reddening of high redshift galaxies implies
that the IGM was enriched to an intergalactic dust-to-gas ratio of less than 3%
of the Milky Way value by a redshift of z=10.
