The effects of stainless steel fiber additions on the resistance of castables to CO and steam were investigated. A series of high and intermediate alumina calcium-aluminate bonded castables was prepared containing several commercial stainless steel fibers. Compressive strength and abrasion resistance of the castables were measured after exposure to high pressure carbon monoxide and steam at 500ºC. Strength and abrasion resistance values were comparable to those of samples without stainless steel fibers. The addition of stainless steel fibers to refractory castables was found to not decrease resistance to carbon monoxide only if the castables were not fired in air prior to CO exposure. Firing in air was found to create oxide layers on the fibers which catalyze CO decomposition, ultimately causing disintegration of the castable. / Master of Science