UV irradiation method is expected to be one of the remediation technology for the trichloroethylene (TCE) gas extracted from contaminated soil. TCE in gas phase has been known to be decomposed by UV irradiation and acid gas which includes some toxic compounds e.g. dichloroacetyl chloride (DCAC), phosgene, chlorine and hydrogen chloride is produced after irradiation. Therefore they have to be rejected before being released in the air. These components were found to be removed by using absorption tower packed with marbles which were wetted by showering water. DCAC was more easily removed than phosgene and chlorine. Since the pH of the waste water from the tower was almost neutral and calcium cation was dissolved at approximately equivalent amount with chloride and dichloroacetate anions, the acid gas components would be removed by hydrolysis and neutralization reactions.