[Magnesium oxide as cause of metal fume fever]

Seven foundry workers are described who all developed pulmonary symptoms and in the majority of cases recurrent occupational fever; the onset of these episodes coincided with the introduction of a new founding technique resulting in exposure to magnesium oxide fumes. The foreman - most exposed because responsible for vaccination of the melted iron with metallic magnesium - developed disabling pneumopathy. The feverish episodes are interpreted as metal fume fever and in 6 patients the pneumopathy is considered to be due to alkalitoxic damage to the small airways and alveoli caused by the magnesium oxide fumes. The seventh patient suffered from allergic asthma bronchiale. Differentiation from hypersensitivity pneumonitis and from humidifier fever of nonallergic etiology is discussed.