With increasing use of lithium-ion power packs, reports of occasional incidents of severely debilitating and sometimes fatal tragedies appear in the news. This review analyzes possible scenarios that trigger such hazards before proceeding to discuss safety mechanisms such as pressure release valves, one-shot fuses, reversible and irreversible positive temperature coefficient elements, shutdown separators, chemical shuttles, non-flammable electrolytes and coatings. (c) 2006 Published by Elsevier B.V.