Structural metal craftsmen work with sheet metal to build and repair structures made from steel and iron. In studies of sheet metal workers results have consistently indicated that about 70% of sheet metal workers employed in the industry for more than 30 years showed at least some indication of asbestos-related abnormalities in the lungs.
Few records of potential occupational asbestos exposure were kept from the period between 1900 and 1979, a time in which the United States used more than 18 million tons of asbestos. It is safe to say, however, that vast amounts of asbestos were used in construction where structural metal craftsmen worked on a daily basis. Often they were in direct contact with asbestos insulation that was sprayed on in industrial construction. During a study of sheet metal workers conducted on 1300 men in the United States and Canada in 1991, 2% of the men were discovered to have mesothelioma as a direct result of the study. These results are typical for studies like this where the researchers look at individuals who are known to have had past asbestos exposure. They had been unaware, prior to that time, that they had any pressing medical issue. Fortunately, other research has indicated that for people who entered the trade after 1970, there is a reduced chance of having asbestos disease, or at least a reduced chance of an asbestos disease that has already shown up.
The ancient Greeks and Romans, even the Pharaohs of ancient Egypt, used asbestos. The Greeks also recognized the dangers of asbestos. They realized that slaves who worked with asbestos had trouble breathing and died younger than other slaves. Studies done in the 1917 and 1918 in the United States confirmed that people who worked with asbestos died younger than the general population.
In 1924 a young woman who had been working with asbestos since her early teens was the first person diagnosed with asbestosis. Studies in England then confirmed that 25% of the asbestos workers showed some signs of asbestos disease in their lungs. In the early 1930s legislation was passed to increase the ventilation in asbestos work areas. By the mid-1930s medical journals published articles indicating that asbestos causes cancer. The dangers and the warnings were ignored, however, and asbestos use continued to rise up until the mid-1970s.
When asbestos is inhaled it gets imbedded in the lungs and the tissue around the lungs. It causes many health problems, but most of them don’t develop for several decades after exposure, making it difficult to determine when and where the person was specifically exposed. Asbestosis and lung cancer are two of many illnesses associated with asbestos, but the most serious disease caused is mesothelioma, a rare form of asbestos cancer. Malignant mesothelioma is a cancer of the membrane surrounding the lungs and lining the chest cavity. The first symptom of mesothelioma is shortness of breath while exercising. The symptoms get worse and include severe chest pain as the cancer progresses. If mesothelioma is caught in the early stage, doctors are sometimes successful in preventing further growth by surgically removing the tumor and the surrounding tissue. If the cancer has already metastasized, surgery is a less effective option. For cancer that has progressed to later stages, doctors rely on a treatment combining chemotherapy and radiation, sometimes in conjunction with surgery. Mesothelioma is highly resistant to most anti-cancer drugs currently available, although there are new drugs being developed on a regular basis. There is no cure for mesothelioma, and few people live more than two years after initial diagnosis.