A hazardous material episode: sulfur trioxide.

Twelve people working next to a chemical plant noted an emission of 2 h. Nine patients complained of a variety of symptoms, including 3 who had pleuritic chest pain, 2 with chest tightness, 2 with vague chest discomfort, 3 with eye irritation, 2 with dizziness, 1 with light-headedness, 1 with cough and 1 with an acidic taste in the mouth associated with nasal irritation. Pulmonary function was 100% of predicted in 5; 77.4, 85.7, 95.7, and 96.7% of predicted in the other 4. Three of the 4 with initial decreased FEV1's (forced expiratory volume in 1 sec) improved. At follow-up, 1 had burning sensation of the tongue and mouth; a second noted burning sensation of his throat, tip of his tongue, and nostrils; and a third had superficial exfoliative-type lesions at the junction of her forehead and scalp. Two complained of continuous pleuritic chest pain. Sulfur trioxide exposure caused self-limited irritant effects.