Asbestos Health Risks
Asbestos Exposure
Most health information on asbestos exposure has been derived from studies of workers who have been exposed to asbestos in the course of their occupation. Asbestos fiber concentrations for these workers were many times higher than those encountered by the general public.
Because asbestos fibers are naturally occurring and extremely aerodynamic, virtually everyone is exposed to asbestos. To be a significant health concern, asbestos fibers must be inhaled at high concentrations over an extended period of time. Asbestos fibers then accumulate in the lungs. As exposure increases, the risk of disease also increases. Therefore, measures to minimize exposure and consequently minimize accumulation of fibers will reduce the risk of adverse health effects.
Asbestos is only dangerous if it is inhaled or ingested. As long as asbestos containing materials are not damaged, the asbestos fibers do not become airborne and do not pose a health threat to the building occupants. During an asbestos building survey, inspectors assess the condition of asbestos containing materials. These conditions do deteriorate over time.
If you find that an asbestos-containing item at the University of Minnesota has been damaged, please contact our office for a hazard assessment. Sean Gabor, manager for the Hazardous Materials Program, can be reached at 612-625-7547 or see the emergency response page for more immediate contact numbers.
Asbestos Diseases
When asbestos fibers accumulate in the lungs, several types of diseases may occur.
Asbestosis
Asbestosis is a scarring of the lung tissue. This scarring impairs the elasticity of the lung and hampers its ability to exchange gases. This leads to inadequate oxygen intake to the blood. Asbestosis restricts breathing leading to decreased lung volume and increased resistance in the airways. It is a slow progressive disease with a latency period of 10 to 40 years.
Mesothelioma
Mesothelioma is a cancer of the pleural lining. It is considered to be exclusively related to asbestos exposure and can be obtained from limited exposure. By the time it is diagnosed, the victim of Mesothelioma usually has less than two years to live. Similar to Asbestosis, Mesothelioma has a latency period of 10 to 40 years.
Lung Cancer
Lung cancer is a malignant tumor of the bronchi covering. The tumor grows through surrounding tissue, invading and often obstructing air passages. The time between exposure to asbestos and the occurrence of lung cancer is 20 to 30 years. It should be noted that there is a synergistic effect between smoking and asbestos exposure, which creates an extreme susceptibility to lung cancer.
Digestive System Cancer
Asbestos may cause stomach and other types of digestive system cancer when asbestos fibers ingested through the mouth are swallowed and logged into the stomach and other areas of the digestive track, eventually causing the disease. Like lung cancer, the latency period for digestive system cancers is about 20 to 30 years.
Airborne Fiber Concentrations
Asbestos is known to be hazardous based on studies of high levels of exposure to asbestos workers and laboratory animals. However, the risks associated with low level, non-occupational exposure are not well established. Therefore, the Environmental Protection Agency (EPA) concludes that there is no safe level of exposure to asbestos fibers. On the other hand, the Occupational Safety and Health Administration (OSHA) has set a Permissible Exposure Limit (PEL at 0.1 fibers per cubic centimeter (f/cc)) for an eight-hour time weighted average. Similarly, the Minnesota Department of Health (MDH) has set the Clean Indoor Air Standard for buildings in the state of Minnesota at 0.01 f/cc.
Lead Health Risks
Lead and Health
Ingestion, inhalation, and absorption at abnormally high level of lead can be harmful. Fortunately, lead exposure to both workers and the general public has been greatly reduced over the last several decades. Current uses of lead are controlled and usually pose no significant environment or health risks. However, according to the Center for Disease Control (CDC), pockets of high exposure still exist in older urban communities where there is deteriorating housing. This creates environmental health risks for both residents and the individuals working in those areas.
Child Exposure
Despite popular belief that exposure to lead among young children is a growing problem in the United States, the average blood-lead level among children has dropped from a national average of over 30 micrograms of lead per deciliter (ug/dl) in the 1930's to average levels in 1994 of about 2.7 ug/dl, according to the U.S. Center for Disease Control. The 1994 findings from the ongoing National Health and Nutrition Examination Survey (NHANES III) indicate that less than half of 1% of the children in the United States have blood lead levels (20 ug/dl) sufficient to warrant medical intervention. Broad averages, of course, can conceal important distinctions among sub-groups of the population.
In brief, the current CDC action levels are:
- Less than 10 ug/dl -- No action;
- 10-14ug/dl -- No interventions of individual children; community-wide primary prevention activities when many children in a community are in this range;
- 15-19 ug/dl - Individual case management, including nutritional and educational interventions and more frequent screening. If the levels persist, environmental investigation, including a home inspection; and
- 20 ug/dl and above - Individual medical evaluation and intervention and the source of lead exposure located and removed.
Adult Exposure
The 1994 NHANES III findings indicated the adult blood lead levels average around 2.4 ug/dl. Since the majority of elevated adult exposures occur in the workplace, the Occupational Safety & Health Administration (OSHA) has created regulations for those environments. OSHA has set lead standards that establish 40 ug/100gr as the desired maximum blood lead level.
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