  We study a class of models of i.i.d.~random environments in general
dimensions $d\ge 2$, where each site is equipped randomly with an environment,
and a parameter $p$ governs the frequency of certain environments that can act
as a barrier. We show that many of these models (including some which are
non-monotone in $p$) exhibit a sharp phase transition for the geometry of
connected clusters as $p$ varies.
