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Indoor Environmental Contaminants in Schools

A wide range of environmental contaminants can affect the health and safety of a school environment. To understand the basics about issues your school may face, choose an indoor environmental contaminant below to learn what it is, what you can do about it and where to get more information.

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Asbestos is a naturally-occurring mineral fiber commonly used in building construction materials for insulation and as a fire-retardant. If undamaged and unlikely to be disturbed, asbestos should be left alone. Disturbing asbestos materials through building renovations or asbestos removal can release asbestos fibers into the air, potentially leading to inhalation and accumulation within the lungs.

Over time, a buildup of asbestos fibers embedded within the lung tissue may lead to serious lung diseases including asbestosis (irreversible lung scarring that can be fatal), lung cancer and mesothelioma, which is a cancer of the chest and abdominal linings. Under the 1986 Asbestos Hazard Emergency Response Act (AHERA), all public primary and secondary schools are required to re-inspect their buildings for asbestos-containing building materials every three years. Inspections must be conducted by EPA-certified asbestos inspectors.


A wide range of hazardous chemicals (toxic, reactive, corrosive and explosive) can be found in science classrooms, labs, art classrooms and storage rooms, and can be used in building and grounds maintenance (e.g., cleaning and pest control). Chemicals that are outdated or unknown pose a particular danger in the event of a fire. Schools may inadvertently purchase chemicals in excessive amounts, store them incorrectly and dispose of them improperly. Exposure to these chemicals can occur during normal use and when they spill or leak.


Formaldehyde is a chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes. This colorless, pungent-smelling gas can cause watery eyes, burning sensations in the eyes and throat, nausea, and difficulty in breathing in people exposed at elevated levels (above 0.1 parts per million). High concentrations may trigger attacks in people with asthma. There is also evidence that some people can develop a sensitivity to formaldehyde. It has also been shown to cause cancer in animals and may cause cancer in humans. Sources of formaldehyde include:

  • pressed wood products (hardwood plywood wall paneling, particleboard, fiberboard)
  • furniture made with these pressed wood products
  • combustion sources and environmental tobacco smoke
  • durable press drapes
  • other textiles and glues
  • For more information, visit EPA's Indoor Air Quality website on Formaldehyde.
  • For further information on formaldehyde and consumer products, call the EPA Toxic Substance Control Act (TSCA) Assistance Line (202) 554-1404.


Sources of lead include drinking water, food, contaminated soil and dust, and air. Lead-based paint is a common source of lead dust. Lead causes various problems, particularly for children and pregnant women, including damage to the brain, kidneys, nervous system and red blood cells. Children are particularly vulnerable as lead exposure in children can result in delays in physical development, lower IQ levels, shortened attention spans and an increase in behavioral problems. Contact with lead-containing dust particles is a potential concern during renovation or repair of surfaces with lead-based paint.

Guidelines for proper removal of lead are available from the Occupational Safety and Health Administration. Federal law also requires contractors that disturb painted surfaces in homes, child care facilities and schools, built before 1978 to be certified and follow specific work practices to prevent lead contamination.


Mercury is found in products such as fluorescent light bulbs, thermostats, thermometers, barometers, batteries and electrical switches and relays. Mercury can permanently damage the brain and kidneys, especially in developing fetuses. Exposure can occur through inhalation of vapors, skin contact (if mercury is accidentally spilled or leaked) or while using chemicals containing mercury. There are now non-mercury or low-mercury product substitutes. If a mercury spill or leak occurs, contact your local health department immediately. EPA encourages schools to prevent spills by removing all mercury compounds and mercury-containing equipment and by discontinuing their use.


Polychlorinated biphenyls (PCBs) are man-made chemicals that persist in the environment and were widely used in construction materials and electrical products prior to 1978. PCBs can affect the immune system, reproductive system, nervous system and endocrine system and are potentially cancer-causing if they build up in the body over long periods of time. Congress banned the manufacture and use of PCBs in 1976, and they were phased out in 1978 except in certain limited uses. PCBs are found in caulk used in windows, door frames, masonry columns and other masonry building materials in many schools and other buildings built or renovated between 1950 and 1978. PCBs are also found in light ballasts.


Radon is a colorless, odorless and tasteless radioactive gas that occurs naturally in almost all soil and rock. Radon can enter schools through cracks or other openings in their foundations. Radon is second only to smoking as the main cause of lung cancer in United States. EPA provides free guidance on how to perform testing, and recommends that all schools test for the presence of radon and take action if test results show radon levels greater than EPA's action level of 4 picocuries per liter, or pCi/L, in air.