Causes respiratory tract irritation. Symptoms of exposure can include coughing, sneezing, shortness of breath, and nasal discomfort. Can cause central nervous system depression. Symptoms of exposure include headache, dizziness, drowsiness, intellectual impairment, pale skin, ringing in the ears, nausea, vomiting, and loss of coordination. Respiratory symptoms may be delayed in onset. High concentrations are an anesthetic, and exposure can lead to unconsciousness.