In most application of Petri nets, resources are modeled as tokens. Unreliable resources pose challenges as existing Petri net theory is deficient in analyzing the impacts of the perturbation due to resource failures. One strategy to analyze a perturbed system is to study its robustness with respect to uncertainties. In this paper, we study the robustness of a class of controlled Petri nets called controlled assembly/disassembly Petri net (CADPN) for assembly/disassembly processes with unreliable resources. The number of tokens in CADPN is not conservative to capture the effects of resource failures. Based on the CADPN model, we characterize different types of tolerable resource failures allowed for a nominal marking of a live CADPN. We show that liveness of a CADPN can still be preserved under tolerable resource failures. (c) 2006 Elsevier Ltd. All rights reserved.