Lead is a chemical element, so it does not form; however, manufacturers produce it by roasting galena, according to About.com. Galena is one of the lead ores, composed primarily of lead sulfate.
Manufacturers produce usable lead metal through recycling of previously used lead or by refining ore miners remove from the earth. Refining ore is a three-part process involving sintering, smelting and refining. Sintering removes the sulfur from the ore through a hot-air combustion process. Smelting heats the metal to a high temperature to isolate lead from other contaminants, and the refining process removes any remaining contaminants, according to the Blacksmith Institute.
Manufactures use lead as the plates in lead-acid batteries. It shields patients and medical workers from x-rays. Lead compounds are important ingredients in paints and insecticides, and lead oxide is essential in producing flint glass and leaded crystal. Lead alloys form pewter, solder, shot, bullets and type metal.
Lead is a cumulative poison, leading to environmental concerns. Its toxic effect has caused its ban in shot for waterfowl. Lead smelting was one of the Blacksmith Institute's top 10 toxic pollution problems for 2011, and it says that lead smelting puts 1.9 million people at risk. The last primary lead smelter in the United States closed in December 2013, according to the Doe Run Company.