Some chemicals are hiding in plain sight, like polyvinyl chloride (PVC), commonly used for plumbing.
Others, like formaldehyde, used as an adhesive in wood products, are not easy to identify because of a lack of labeling on building products.
The same can be said of pesticides and flame retardants, epoxy coatings, polyurethane and bisphenol A (BPA).
Two emerging recycled products -- fly ash and synthetic gypsum, both byproducts of coal-fired power plants -- are causing some alarm.
Synthetic gypsum is used in 45 percent of today's wallboard, said Jim Vallete, a senior researcher with the Healthy Building Network, a nonprofit that advocates for greater transparency in building materials.
According to tests done by the EPA, it's also been shown to have higher concentrations of mercury, a known developmental toxicant, than regular wallboard.
Coal fly ash, which also can contain toxic levels of mercury and other toxins, is used as filler in cements, wood products, carpeting and other building materials.
Another emerging building material, spray polyurethane insulation, comes with health concerns, as well. While it is easy to apply and contributes greatly to a building's energy efficiency, it is a suspected neurotoxicant.
BPA is another. A 2008 National Institutes of Health study concluded that BPA -- often used to line plastic and metal containers to prevent corrosion -- is a likely contributor to the development of breast cancer and cancers of bone marrow and lymph nodes, among other blood-producing areas of the body.
While consumers have expressed concerns about the toxicity of BPA-lined food and beverage containers, the U.S. Food and Drug Administration has rejected a ban on them. The FDA encourages food and beverage manufacturers to voluntarily share how much and where BPA may be in packaging or to eliminate it. And some have.