This report describes the clinical and pulmonary function manifestations found in a 37-yr-old commercial abalone diver who developed diffuse lipoid pneumonitis due to inhalation of aerosolized mineral oil contained in the unfiltered air generated from his surface air compressor. Four years later, the patient continued to be symptomatic with shortness of breath and dyspnea during exertion, and repeat physiologic evaluation continued to demonstrate findings of a restrictive ventilatory defect.