A 76-year-old man presented with a 7-year history of dyspnea on exertion. He had received intermittent medical treatment that only relieved his symptoms. The patient had smoke for 25 pack-years and quit at the age of 66. According to his medical history, there was no evidence of tuberculosis.
Table 1 presents the patient's occupational history. He reported 10 years of occupational exposure to fumes from a heat-treatment procedure and silica dust. He had worked at a wheel manufacturing company from Feb 7, 1965 to Mar 7, 1975.
The working process at the factory is summarized as follows. Lumps of scrap metal were poured into a smelting furnace, melted, and then transported to a mold to be solidified. The solid mold was then sent to the heat treatment procedure area. The patient's main duty was to transport the casting by hoisting it or using a crane to move it to the heating furnace, and then control the temperature. All of these processes including those at the smelting furnace were all performed in an area covering about 997.73 m2. Bunker-C oil was the fuel source for the heating furnace. The patient stated he had inhaled a large volume of smoke from the soot produced when controlling the temperature or turning the ignition on. There were no local ventilation systems, respiratory protectors, or partitions to isolate the shaking out and finishing processes; therefore, exposure to crystallized silica from adjacent areas is likely.
The patient typically worked two shifts each week and had a few days off monthly. In addition to working at the wheel manufacturing company, he also worked for 5 years as a laborer on construction sites. After he stopped working on construction sites, he installed boilers and worked general manual labor for approximately 25 years. Since 2003, he has been working as janitor in an apartment complex.
On May 21, 2012, a chest X-ray and CT scan revealed an evidence of hyperinflation with emphysematous changes in both upper lobes; he was diagnosed with emphysema. A month later (Figures 1, 2), a pulmonary function test was done that included a post-bronchodilator forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and FEV1/FVC% that were 2.20 L (67% of the predicted value), 1.12 L (52% of the predicted value), and 51%, respectively, which all indicate moderate COPD.