In addition to the smog on the horizon searing our lungs, the sun's ultraviolet rays baking our skin, and the distracted driver bearing down on us as we cross the street, we can add to our list of potential health concerns the walls, flooring, pipes and other components of the buildings we live, work and play in.
As the post-industrial era deepens, maybe we should start wearing hazmat suits.
According to the U.S. Environmental Protection Agency, Americans spend approximately 90 percent of their time indoors. While we might think we're safer inside, building materials, which don't currently have ingredients lists, are getting more complex -- and sometimes more toxic -- all the time.
Health concerns about our indoor environment are nothing new. Asbestos, a naturally occurring mineral once widely employed by the building industry because of its insulating and fire-retarding properties, has been shown to cause lung cancer and mesothelioma. Its use is now tightly regulated.
Other building materials may pose greater risks.
Knowns and unknowns
The concern today is not primarily over things that we know about. It's about the potential health effects of chemicals that are components of building materials -- and, at times, the materials themselves -- of whose presence, or toxicity, we are often unaware.
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.
Lack of transparency
A lot of the time, there's no real way for a builder -- or us -- to know if PVC, BPA, coal fly ash, synthetic gypsum or other potentially hazardous materials are in a building.
Perkins + Will, a Chicago-based architectural firm, has made this unknowability a focus. The firm runs a project that lists building material components (along with their known or suspected health effects) in an effort to encourage transparency in the building field.
The project, and its precautionary list of 25 building materials it recommends builders and consumers be aware of, has gained national attention.
The transparency project has logical beginnings. When the firm set out to design a cancer center in Brooklyn, N.Y., which opened in 2003, it wanted to do the sensible thing: construct and outfit the center with building materials that contained no known or suspected carcinogens.
Turns out this was an impossible task -- though the firm came close to its goal.
There's no way to have perfectly harmless building materials, said Peter Syrett, a Perkins + Will architect who runs the firm's transparency project with a colleague.
"Name a 'green' product? I really can't," Syrett said. "It's not how we (as a culture) do things now."
It's not about finding a perfectly harmless product, however.
Beyond a return to the prehistory of mud huts and reed cabanas, building products, as fully modern materials, come in at best only shades of green, Syrett said -- one of the compromises of civilization.
As awareness grows there are more tools for builders to use. The Pharos Project, an endeavor of the Healthy Building Network, aims to provide information on where to get building materials that have full disclosures.
The new green
Some, including the almighty market, see health as the new green.
"Not everybody understands what sustainability is," said Aaron Smith, director of sustainable building solutions at Assa Abloy, a global manufacturer of door-related products, "but most people understand human health."
Assa Abloy, in response to growing customer demand, Smith said, has found less-toxic materials to plate its metal goods with, has eliminated some hazardous cleaning chemicals, has removed PVC from all of its products where found, and is trying to eliminate formaldehyde from all its door products.
Removing PVC was doable, Smith said, but formaldehyde, a cheap, effective bonding agent used in many wood products and which customers are increasingly demanding elimination of, is proving more difficult because of a lack of economical substitutes.
Gray shades of green
And as health concerns rise with building products, sometimes the "green" building industry is at odds with itself.
Sometimes, recycled content has adverse health effects, said Bill Walsh, founder and executive director of the Healthy Building Network.
For example, more stringent air pollution controls require coal-fired power plants to clean their combustion exhaust. The result is fewer heavy metals and toxicants in the air, but more in the existing fly ash and synthetic gypsum, which are used more as a recycled product in building materials.
This is just one example of the complexity of modern buildings, the health concerns they provoke, and the minefield we must pass through as we enter the next era of sustainability (and what it means).
Whatever happens, it won't be a black-and-white solution, said Chris Youssef, an interior designer at Perkins + Will who helps run the firm's transparency project with Syrett.
In reality, it's a weighing system, Youssef said. "Every modern material has a problem with it," he said.
"People want red lists," he said. "It's not about that."