The effects of oxides of nitrogen inhalation are reported in a 21-year-old garexposed to silage gas. Initial nausea, cough and fever remitted, but respiratory failure developed 3 weeks later. Roentgenograms and lung function studies revealed pulmonary in the adult edema, volume restriction, and severely impaired gas exchange. Needle biopsy showed a nonspecific interstitial pneumonia. With steroid therapy all functional parameters except diffusing capacity returned to normal. Failure to inquire about non-occupational activities led to delayed diagnosis. A brief review of toxic effects of nitrogen oxides is presented.