On May 18, 2001 a destructive fire and explosion accident occurred in an acrylic resin manufacturing plant located in the northern part of Taiwan. More than 100 people were injured and totally 46 plants including 16 high-tech companies nearby were severely damaged. The resulting blast wave destroyed and shattered many large and small windows of residences within half-a-kilometer. The immediate cause turned out to be a vapor cloud explosion and the blast mass was estimated to be equivalent to 1000 kg of TNT. However, the original cause was found to be a runaway reaction of a 6-ton reactor that contained methyl acrylate, methyl alcohol, acrylonitrile, isopropyl alcohol, acrylic acid, methacrylic acid, and benzoyl peroxide. The investigation and experimental runaway results revealed that during the runaway, the temperature had risen rapidly from 60degreesC to about 170-210degreesC and the maximum temperature rising rate could reach 192 K min(-1). Since the final temperature of the process was much higher than the boiling points of all the reactants, vapors generated inside the reactor were released to the atmosphere. Certain hazards analysis and calorimetric tests to ensure that similar runaway accident should not occur again were performed as part of this study. (C) 2002 Elsevier Science Ltd. All rights reserved.