Two explosions occurred at a petrochemical plant. One explosion occurred in 1987 and the other in 2002. The explosions resulted in an estimated 34 tons of chemical residues being released and absorbed into the ground and polluted the ground water. The contaminated ground water was the sole source for the local water supply and provided water to 2.4 million people. The chemicals included benzene, TCE, and PCB. Discuss the steps that you would take to conduct a risk assessment of this situation. What information would you need to conduct this risk assessment and how would you obtain it?