Odorants have been proposed as a reliable, inexpensive means to enable leak detection for hydrogen systems and increase public safety. However, traditional odorants cause problems for fuel cell systems. This paper examines the use of odorants for fuel cell systems, including the hydrogen storage. Current odorants and potential odorants have negative impacts on fuel cell performance. Odorants also appear to be problematic for most of the advanced hydrogen storage options. If odorants are used, the odorants will probably need to be removed from the hydrogen prior to the storage medium. Current hydrogen detectors are more reliable than the odorant-human detection system and should provide increased safety. (C) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.