In a process plant, leaks of flammable liquid may occur from various equipment. The temperature and pressure of the liquid varies through the plant. In a risk analysis, leaks have been included as a hazardous event. Three leak sizes have been defined, small, medium, and large, and event trees have been developed for these three leak sizes. The probability of ignition of a leak is based on average data from process plants and the probabilities of failure of various safety systems are based on fault tree analysis, with input data from different handbooks. Fires and explosions resulting from an ignited leak are modeled with simple empirical equations that are used to calculate the size of a fire, the heat load, and explosion overpressure. Based on this very brief description, identify some potential sources of model uncertainties and parameter uncertainties.