  In deposition with a poisoning species, we show that the transition to a
blocked or pinned phase may be viewed as an absorbing transition in the
directed percolation (DP) class. We consider a ballistic-like deposition model
with an active and an inactive species that represents its basic features and
exhibits a transition from a growing phase to a blocked or pinned phase, with
the deposition rate as the order parameter. In the growing phase, the interface
width shows a crossover from the critical W ~ t behavior to Kardar-Parisi-Zhang
(KPZ) scaling, which involves DP and KPZ exponents in the saturation regime. In
the pinned phase, the maximum heights and widths scale as H_s ~ W_s ~
(p-p_c)^{nu_//}. The robustness of the DP class suggests investigations in real
systems.
