| A documented absence of previous respiratory complaints. |
| The onset of symptoms should occur after a single specific exposure. |
| The exposure should be to a gas, smoke, fume, or vapor with irritant qualities that was present in very high concentrations. |
| The onset of symptoms should occur within 24 hours of exposure and should persist for at least three months. |
| The symptoms should simulate asthma with cough, wheezing, and dyspnea. |
| Pulmonary function tests may or may not show airflow obstruction. |
| Methacholine challenge should be positive. |
| Other types of pulmonary diseases should be ruled out. |
