A two-dimensional, finite element model for simulating coupled multiphase flow and multicomponent transport in planar or radically symmetric vertical sections. MOFAT evaluates flow and transport for water, nonaqueous phase liquid (NAPL), and gas. The program also can be used when gas and/or NAPL phases are absent in part or all of the domain. The flow module can analyze either two-phase flow of water and NAPL in a system of constant gas pressure or explicit three-phase flow of water. The transport module can accommodate up to five components partitioning among water, NAPL, gas, and solid phases, assuming either local equilibrium interphase mass transfer or first-order kinetically controlled mass transfer.