By the 1980s, Fluor's primary business was building large refineries, petrochemical plants, oil pipelines and other facilities for the gas and oil industry, especially in the Middle East. By 1981, Fluor's staff had grown to 29,000 and revenue, backlog, and profits had each increased more than 30 percent over the prior year. However, by 1984 the mining operation was causing heavy losses and the oil and gas industry Fluor served was in a worldwide recession due to declining oil prices. From 1981 to 1984, Fluor's backlog went from $16 billion to $4 billion. In 1985 it reported $633 million in losses. David Tappan took Bob Fluor's place as CEO in 1984 after Bob died from cancer and led a difficult restructuring.