This paper describes the durability implications of neat hydrogen on electronically operated pulse-width modulated fuel injectors. Four injector types were evaluated, some of which were modified through the employment of solid lubricant coatings and surface treatments-creating a total of eight candidate H-2 injector variants. For each injector variant, test stand durability data was recorded until failure or the accumulation of more than 800 h (64 million injector cycles, or similar to45 k vehicle miles) of operation on neat hydrogen. The injector durability experiments were conducted employing pulse widths and frequencies representative of engine operation at moderate speed, high speed, and maximum speed conditions. The results from these experiments ranged from failure in < 80 h to several injector variants successfully completing more than 800 h of testing. (C) 2002 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.