ABSTRACT
Mild exposure is irritating, and causes coughing. High concentrations may produce laryngospasm. Usually, the initial symptoms are minor, but can be followed after two to 30 hours by increasing respiratory distress which may be very severe. Sometimes, profound hypoxia can develop, and may even result in death. This is caused by pulmonary oedema. The clinical features may be difficult to differentiate from pneumonia. Two to six weeks after this (in the survivors), another acute respiratory illness – bronchiolitis – can occur, even without further exposure, this usually takes two or three weeks to resolve, but, again, this may prove fatal.
