Three heuristics are proposed to solve the maximin formulation for siting p facilities on a network considering a pollution dispersion equation and facility interaction. Initially, the single facility problem is approached by building up polygons which model pollution spread about the nodes of the network. This is extended in the first heuristic to the p facility problem. The second combines both the p-maximin and p-maxisum objectives in a lexicographic manner. The third is based on recent developments of Simulated Annealing. The proposed heuristics are evaluated for up to six facilities on a set of randomly generated networks having 20 to 40 nodes and low or medium arc density.