Asbestos production and use has decreased dramatically over the years in the United States. Exposure to asbestos may occur from ambient air, indoor air, or water. Effects on the lung are a major health concern from asbestos, as chronic (long-term) exposure to asbestos in humans via inhalation can result in a lung disease termed asbestosis. Asbestosis is characterized by shortness of breath and cough and may lead to severe impairment of respiratory function. Cancer is also a major concern associated with asbestos exposure, as inhalation exposure causes lung cancer and mesothelioma (a rare cancer of the thin membranes lining the abdominal cavity and surrounding internal organs), and possibly stomach, laryngeal, and colorectal cancer. EPA has classified asbestos as a Group A, known human carcinogen.
Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS) (2), which contains information on the carcinogenic effects of asbestos including the unit cancer risk for inhalation exposure, and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for Asbestos. (1)
- Asbestos production and use in the U.S. has decreased dramatically over the years due to healthconcerns and regulations banning its use. (1)
- U.S. production of asbestos decreased from 300 million pounds in 1973 to 6 million pounds in 2002. (3)
- In 2010, there were two U.S. suppliers of asbestos and most of the asbestos used in the U.S. is imported from Canada. (3)
- Asbestos has been used in building materials, paper products, asbestos-cement products, friction products, textiles, packings and gaskets, and asbestos-reinforced plastics. (1,4)
- Many uses have been prohibited, including the spraying of asbestos-containing material on buildings and structures for fireproofing, insulation and decorative purposes, asbestos inclusion in patching compounds and asbestos heat shields in hair dryers. Asbestos substitutes continue to be developed. For example, nonasbestos friction materials are currently being used in disc brake pads, and substitutes have been developed for drum brake linings. (1)
Sources and Potential Exposure
- Airborne exposure to asbestos may occur through the erosion of natural deposits in asbestos bearing rocks, from a variety of asbestos-related industries, or from clutches and brakes on cars and trucks. The concentrations in outdoor air are highly variable. (1,4)
- Asbestos has been detected in indoor air, where it is released from a variety of building materials such as insulation and ceiling and floor tiles. It is only released, however, when these building materials are damaged or disintegrate. (1)
- Asbestos may be released into water from a number of sources, including erosion of natural deposits, corrosion from asbestos-cement pipes, and disintegration of asbestos roofing materials with subsequent transport into sewers. (1,4)
Health Hazard Information
- No studies were located on the acute (short-term) toxicity of asbestos in animals or humans. (1)
Chronic Effects (Noncancer):
- Chronic inhalation exposure to asbestos in humans can lead to a lung disease called asbestosis, which consists of a diffuse fibrous scarring of the lungs. Symptoms of asbestosis include shortness of breath, difficulty in breathing, and coughing. Asbestosis is a progressive disease, i.e., the severity of symptoms tends to increase with time, even after the exposure has stopped. In severe cases, this disease can lead to death, due to impairment of respiratory function. (1,2)
- Other effects from asbestos exposure via inhalation in humans include pulmonary hypertension and immunological effects. (1,2)
- Feeding studies in animals exposed to high doses of asbestos have not detected any evidence of adverse toxic effects. (1,2)
- EPA has not established a Reference Concentration (RfC) or a Reference Dose (RfD) for asbestos. (2)
- No studies were located on the developmental or reproductive effects of asbestos in animals or humans via inhalation. (1)
- Birth defects were not noted in the offspring of animals exposed to asbestos in the diet during pregnancy. (1)
- No effects on fertility were observed in animals exposed to asbestos in the diet during breeding, pregnancy, and lactation. (1)
- A large number of occupational studies have reported that exposure to asbestos via inhalationcauses lung cancer and mesothelioma (a rare cancer of the membranes lining the abdominal cavity and surrounding internal organs). (1,2,3)
- Individuals who smoke and are also exposed to asbestos have a greater than additive increased risk of developing lung cancer. (1,2,3)
- Long and intermediate-range asbestos fibers (>5 micrometers (µm)) appear to be more carcinogenic than short fibers (<5 µm). (1)
- Some occupational studies have reported an increased risk of stomach, laryngeal, or colorectal cancer from asbestos exposure. However, the data are not as strong as that for lung cancer and mesothelioma. (1)
- Epidemiological studies have not found a clear association between asbestos exposure in drinking water and an increased risk of stomach cancer. (1,2,3)
- A series of large-scale lifetime feeding studies in animals reported that exposure to intermediate-range asbestos fibers increased the incidence of a benign tumor of the large intestine in male rats, while short-range asbestos fibers showed no significant increase in tumor incidence. (1)
- EPA has classified asbestos as Group A, human carcinogen. (2)
- EPA uses mathematical models, based on human and animal studies, to estimate the probability of a person developing cancer from breathing air containing a specified concentration of a chemical. EPA calculated an inhalation unit risk estimate of 2.3 × 10-1 (fibers/cm3)-1. EPA eestimates that, if an individual were to continuously breathe air containing asbestos at an average of 0.000004 fibers/cm3 over his or her entire lifetime, that person would theoretically have no more than a one-in-a-million increased chance of developing cancer as a direct result of breathing air containing this chemical. Similarly, EPA estimates that breathing air containing 0.00004 fibers/cm3 would result in not greater than a one-in-a-hundred thousand increased chance of developing cancer, and air containing 0.0004 fibers/cm3 would result in not greater than a one-in-ten-thousand increased chance of developing cancer. (2)
- Asbestos is the name applied to a group of six different fibrous silicate minerals that occur naturally in the environment. (1)
- There are two groups of asbestos minerals: serpentine and amphibole. There are also nonfibrous forms of serpentine and amphibole which are not asbestos. (1)
- Serpentine asbestos are relatively long and flexible crystalline fibers that may be woven, and includes the mineral chrysotile, and amphibole asbestos are more brittle than serpentine asbestos and includes the minerals amosite, crocidolite, tremolite, anthophyllite, and actinolite. (1)
- Asbestos is neither volatile nor soluble; however, small fibers may occur in suspension in both air and water. (1)
Read the full EPA PDF on the above Hazardous Air Pollutant with references below.
Relavance to personnel who served in the Air Corps
- Pipework in a number of Air Corps buildings was lagged with Asbestos most notably the Apprentice hostel was lagged with badly damaged Asbestos until the early 1990s. So every apprentice who served from approximately the 55th Apprentice Class and before was exposed to asbestos in their sleeping environment.
- The apprentice hangar roof was made from asbestos.
- Parts of engine shop ceiling was discovered to be made from asbestos when it partially collapsed and dislocated the shoulder of a machinist working beneath it.
- The fire crew wore special fire suits made from asbestos.
It is likely that we have missed many areas of asbestos usage in both Baldonnel and Gormanston aerodromes so please help us by listing usage locations in comments section below.