Emergency situations such as biological or chemical incidents require prompt decision making. The problem is that the authorized personnel responsible for conduction the response operations might lack the knowledge about the agent's biological, chemical and epidemiological characteristics that would influence the impact of the incident. Thus the effect of response operations on lives and assets could hardly be anticipated. The paper suggests simulation based approach to provide appropriate decision making support in such situations. The simulation would imitate the development of an emergency situation under various scenarios and help to determine the proper response operations by which the casualties and loss of assets would be minimized. The aim of the paper is to present the simulation of a spread of an agent in an environment and the corresponding impact on population. The simulation is based on a model with incorporated knowledge about environmental and agent characteristics such as weather conditions, transmission, fatality, incubation period combined also with demographic information. The provided simulation forms a part of the proposed non-military decision support framework for emergency response operations during biochemical incidents.