  Deriving the physical properties of red supergiants (RSGs) depends upon
accurate corrections for reddening by dust. We use our recent modeling of the
optical spectra of RSGs to address this topic. We find: (1) Previous broad-band
studies have underestimated the correction for extinction in the visible, and
hence the luminousities, if derived from V. (2) A significant fraction of RSGs
in Galactic OB associations and clusters show up to several magnitudes of
excess visual extinction compared to OB stars in the same regions; we argue
that this is likely due to circumstellar dust around the RSGs. (3) RSGs
contribute dust grains at the rate of $3 \times 10^{-8} M_\odot$ yr$^{-1}$
kpc$^{-2}$ in the solar neighborhood, comparable to what we estimate for
late-type WC Wolf-Rayet stars, $1 \times 10^{-7} M_\odot$ yr$^{-1}$ kpc$^{-2}$.
In the solar neighborhood this represents only a few percent of the dust
production (which is dominated by low-mass AGBs), but we note that in
low-metallicity starbursts, dust production by RSGs would likely dominate over
other sources.
