During the restructuring, Fluor's core construction and engineering work was diversified into 30 industries including food, paper manufacturers, prisons and others to reduce its vulnerability to market changes in the oil and gas market. In the 1990s, the company tried to change its image, calling itself a "diversified technical services" firm. It started offering equipment rentals, staffing services, and financing for construction projects. The company began offering environmental cleanup and pollution control services, which grew to half of its new business by 1992. Fluor's mining business grew from $300 million in 1990 to $1 billion in 1994. The US government passed environmental regulations in 1995 that led to growth for the Massey Coal Co. business, because it had large reserves of low-sulfur coal. In 1992, Fluor sold its ownership of Doe Run Company, the world's largest producer of refined lead, which was losing money at the time due to declining lead prices. By 1993, Fluor had revenues of $4.17 billion and 22,000 staff.