To predict the hazard-induced risks of buildings and infrastructures and assess the losses caused by hazards, the fragility curve method is a common quantitative risk assessment procedure for civil structures. It has been popularly used for decades for different hazards including earthquakes, hazardous winds, tsunamis, and fires. However, there are limited reports regarding blast risk assessment of buildings using the fragility curve method. This study developed empirical blast fragility curves for wood residential buildings using the real 2013 West fertilizer plant explosion data. The development processes included five key steps: (1) selecting and calculating the blast hazard intensity measure and the air-blast incident overpressure; (2) selecting the damage states rating systems and classifying the damage state of each damaged building; (3) determining the frequency distribution of damaged buildings for each damage state; (4) proving the cumulative lognormal distribution function to describe the fragility relationship between the blast damage states and the blast hazard intensity measure; and (5) constructing the empirical fragility curves by fitting the building damage information to the selected fragility relationship distribution function. The resulted blast fragility curves of this study can be used by government officials to predict blast-induced damages of residential buildings, to plan the optimal locations and operational capacities of emergency facilities, to estimate total economic losses due to potential explosions, and to plan the social, physical and economic resilience of communities.