The activation and anti-poisoning characteristics of LmNi(4.8)Al(0.2) hydrogen storage alloy are investigated. The incubation period of LmNi(4.8)Al(0.2) ranges from about 8 h to just a few minutes with activation temperatures of 20 and 80 degrees C, respectively. Poisoning effects become more problematic with a higher concentration of CO and a greater number of absorption/desorption cycles. The poisoning can be effectively inhibited by raising the temperature during hydrogen absorption/desorption. The poisoning by H2S is less than that of CO. The poisoned LmNi(4.8)Al(0.2) alloy can be successfully reactivated by purging with high purity hydrogen gas. (C) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.