This paper provides a review of total flooding gaseous agents as Halon 1301 substitutes. Agents are compared, based on published data, in terms of their environmental impact, toxicity, fire suppression performance, and acid gas production from small-to full-scale tests. These data are also collected in tables. Acceptability of an agent by regulatory authority is mostly determined by agent toxicity. Based on the toxicity criteria set by the U.S. Environmental Protection Agency (EPA), five commercial halocarbons (FC-218, FC-3-1-10, HFC-23, HFC-227ea, and HCFC Blend A) and three commer cial inert gases (IG-01, IG-55, and IG-541) are acceptable for total flooding in normally occupied spaces. They are less effective by weight or volume than Halon 1301, with additional limitations and weaknesses.