Among its thousands of uses, asbestos insulation is regularly used to prevent excessive heat loss from furnaces, either by spraying the insulation on, or by using asbestos boards to enclose furnaces. Additionally, because of the ease of making asbestos cloth, it has been used extensively in hot environments as protective clothing. Asbestos clothing was considered standard in Britain until the late 1970s. Use in the United States was similar.
Furnace men, smelter-men and pourers all work in an industry where until at least the early 1980s, they could expect to have been using some sort of asbestos-containing protective gear. Studies to measure the amount of asbestos fibers given off by individual pieces of clothing vary in the amount of airborne asbestos in the ambient air. What the studies are consistent in showing, however, is that the more exposure to asbestos a person gets, the more likely it is that the person will get some sort of asbestos-related illness such as mesothelioma or asbestosis.
Additionally, studies have shown that even when binding agents were used to try to keep asbestos dust from separating from the main article, many of the binding agents did not work at the high temperatures associated with smelting. Men in this industry who worked directly with the furnaces and the very hot metal coming out of them are among those most likely to have gotten high levels of exposure over a long period of time. Asbestos clings to clothes and hair as well, so any protective coverings that came in contact with the worker’s ordinary clothing could have sloughed off asbestos dust onto clothes the worker then wore home. In this way family members could also be unknowingly exposed to asbestos even if they never approached the place of employment.
When asbestos fibers are disturbed, for instance when protective clothing made from asbestos brushes against another surface, the fibers can break off into tiny pieces that are very light and can easily become airborne. Currents of warm air keep the fibers in the air longer than cool air; because a lot of the furnace and smelting rooms in the past were not well ventilated, concentrations of asbestos in the air could build up over the workday.
When a person inhales asbestos it enters the respiratory system. The dust adheres to the tissue in and around the lungs causing irritation and inflammation that eventually causes scarring. Asbestos is also a carcinogen that causes several different forms of asbestos cancer. One of the forms is an otherwise rare type of cancer called malignant mesothelioma, the most common form of which affects the lining of the chest and is known as pleural mesothelioma. It can take anywhere from 15 to 50 years after exposure for the mesothelioma to manifest. The first symptom is feeling slightly out of breath during exercise. This is such a nonspecific symptom that few people, including doctors, recognize it as a sign of a serious health problem. As the cancer gets worse, breathing becomes more difficult and chest pain develops.