  We present late-time (590-994 d) mid-IR photometry of the normal, but
highly-reddened Type IIP supernova SN 2002hh. Bright, cool, slowly-fading
emission is detected from the direction of the supernova. Most of this flux
appears not to be driven by the supernova event but instead probably originates
in a cool, obscured star-formation region or molecular cloud along the
line-of-sight. We also show, however, that the declining component of the flux
is consistent with an SN-powered IR echo from a dusty progenitor CSM. Mid-IR
emission could also be coming from newly-condensed dust and/or an ejecta/CSM
impact but their contributions are likely to be small. For the case of a CSM-IR
echo, we infer a dust mass of as little as 0.036 M(solar) with a corresponding
CSM mass of 3.6(0.01/r(dg))M(solar) where r(dg) is the dust-to-gas mass ratio.
Such a CSM would have resulted from episodic mass loss whose rate declined
significantly about 28,000 years ago. Alternatively, an IR echo from a
surrounding, dense, dusty molecular cloud might also have been responsible for
the fading component. Either way, this is the first time that an IR echo has
been clearly identified in a Type IIP supernova. We find no evidence for or
against the proposal that Type IIP supernovae produce large amounts of dust via
grain condensation in the ejecta. However, within the CSM-IR echo scenario, the
mass of dust derived implies that the progenitors of the most common of
core-collapse supernovae may make an important contribution to the universal
dust content.
