Kinetics and mechanisms of Cl atom initiated oxidation reactions of CF3CH2CHF2 (HFC-245fa) were investigated by long-path FTIR spectroscopic methods at 297 +/- 2 K. The Cl atoms initiated the reaction mainly via H-atom abstraction from the terminal carbon (greater than or equal to 95%) to produce a CF3CH2CF2 radical. Subsequent reactions in 700 Torr of air produced CF3CHO and CF2O as the primary products. Secondary reactions of CF3CHO with Cl atoms led to the formation of CF3C(O)OH, CF3OH, CO2, and CF3OOOCF3 in the experimental system. However, under atmospheric conditions, CF3CHO would undergo a series of rapid oxidation and decomposition reactions ultimately leading to HF and CO2, and no long-lived organic decomposition products would be produced.