Four young healthy adults were studied physiologically after accidental inhalation of chlorine gas. All patients were symptomatic with cough, tightness in the chest, and shortness of breath. All had restrictive ventilatory defect with impaired diffusing capacity. There was evidence of some obstruction in small airways. There was inconsistent evidence of obstruction in large airways. All lung function impairment was temporary and cleared entirely within one month. There was no residual lung damage.