Objective the purpose of this study is to determine if inhalation of 2% peracetic acid aerosol is harmful to humans and laboratosy animals. Methods Rats were kept in an isolator containing 2% peracetic acid aerosol in a concentration of 1g/m^3 for 30 minutes. Pulmonary alterations in the rats were assessed by pathological examination. Results Pathological changes in the rat lungs to a varying degree were caused by this procedure. Conclusions Disinfection under the barrier environment with 2% peracetic acid aerosolis irritative and harmful to laboratory workers and animals.