Abstract
In conventional fault tree analysis, probabilities of the basic events were treated as precise values; sometimes this probability does not correspond to real situations of systems because of ambiguity and the imprecision of some basic events. In order to overcome this disadvantage, a new fuzzy probabilistic method, based on the fuzzy set theory and the Buckley approach, is used in the fault tree analysis for quantifying the basic event uncertainty. According to failure modes, a fault tree of a milk manufacturing unit is constructed. Failure in the milk manufacturing workshop is analysed using the proposed method.