Chemical pneumonitis is the most common pulmonary complication, and is most likely to occur following aspiration of a hydrocarbon with low viscosity, high volatility, and low surface tension. Symptoms occur quickly and include cough and dyspnea. Physical examination may reveal tachypnea, wheezing, grunting, and an elevated temperature. Radiographic findings may lag behind the clinical picture by 4 to 24 hours; however, most radiographic abnormalities are apparent within 6 hours. Less common pulmonary complications include pneumothorax, pneumomediastinum, and pneumatocele.