A pulse radiolysis system was used to study the kinetics of the reaction of CF₃CFHO₂ with NO₂. By monitoring the rate of the decay of NO₂ using its absorption at 400 nm the reaction rate constant was determined to be k=(5.0±0.5)×10^-12 cm³ molecule^-1 s^-1. A long path length Fourier-transform infrared technique was used to investigate the thermal decomposition of the product CF₃CFHO₂NO₂. At 296 K in the presence of 700 Torr of air, decomposition of CF₃CFHO₂NO₂ was rapid (greater than 90% decomposition within 3 min). The results are discussed in the context of atmospheric chemistry of CF₃CFH₂ (HFC-134a).