A group of organizations promoting energy-efficient housing has published a report on insulation and air-sealing products, concluding that chemical emissions from some commonly used building materials can pose long-term health risks.
A Guide to Healthier Upgrade Materials comes from a group called Energy Efficiency for All and is based on research by the Natural Resources Defense Council, the International Living Future Institute, the Healthy Building Network, and others.
Although written specifically for those working on energy upgrades for affordable multifamily projects, the recommendations should be useful across the building industry, the authors said.
The benefits of insulating and air sealing are clear, the report said, but upgrades also can introduce a variety of chemical hazards, including halogenated flame retardants, formaldehyde-based binders, isocyanates, and phthalate plasticizers.
“The health effects of these chemicals include reproductive and developmental impacts, carcinogenicity, and the ability to cause or exacerbate asthma,” the report notes. “Moreover, some of these chemicals persist and accumulate in the environment and in people and thus can have broad-reaching, long-term impacts.”
The health ranking for various types of insulation and air-sealing products favors fiberglass and cellulose insulation over foam insulation, especially foams that are mixed on site. It also recommends acrylic-based sealants with low levels of volatile organic compounds over modified polymer and polyurethane sealants that typically contain phthalates and other chemicals.
The potential for chemical emissions is key because Americans spend an average of 90% of their time inside, the report says. Chemical components of insulation and air-sealing materials also pose threats to the workers who manufacture, install, and dispose of the products.
Researchers blamed the problem on a weak regulatory environment, misconceptions about chemicals in building products and their impact on health, and a lack of disclosure about chemical content. A 1976 law on toxic substances grandfathered some 62,000 chemicals without any evaluation, for example, and in the 40 years since then the Environmental Protection Agency has required health testing on only about 200 of them.
“Chemicals are assumed safe unless proven otherwise,” the study says. “And even for restricted chemicals the actual restrictions can be minimal.”
Ranking building insulation
The report includes rankings for building and pipe insulation, ranging from the very best to the very worst products on the market. Researchers liked expanded cork board the best, but also included loose-fill fiberglass, dense-pack fiberglass, spray-applied fiberglass and fiberglass batts in the same “green” category.
Also recommended, although not as highly, were fiberglass batts, cellulose and cotton batts, loose-fill cellulose, dense-packed cellulose, and wet-blown cellulose.
At the bottom of the rankings were spray polyurethane foam (the worst) and extruded polystyrene (XPS). In the middle were mineral wool batts and boards, polyisocyanurate, and expanded polystyrene (EPS). Similarly, the report recommends formaldehyde-free fiberglass pipe insulation over polyethylene foam or elastomeric foam pipe insulation.
“Not all products toward the top of the ranking are expensive or limited in availability,” it notes. “Commonly used fiberglass and cellulose insulations are some of the highest ranked from a health perspective, and have the lowest installed cost for any given R-value. While the R-value per inch is higher for many foam products, the R-value per dollar is not.”
Air-sealing products that are applied wet emit “chemicals of concern” as they dry or cure, the report says, so solid forms of sealants are usually better choices. General recommendations include:
- Caulk-type sealants are better than spray-foam sealants.
- Foam sealing products that are not reacted on site are better than those that are.
- Avoid products with phthalate plasticizers.
- Look for acrylic-based sealants with low levels of volatile organic compounds.
- For HVAC sealing, use foil-backed butyl tape.
- Avoid products that are marketed as antimicrobial.
The best sealants from a health standpoint were, in order, non-combustible sodium silicate caulk, expanding polyurethane foam sealant tape, acrylic latex sealant, siliconized acrylic sealant, and intumescent acrylic firestop sealant.
The three worst were one-component polyurethane sealant (at the very bottom), one-part polyurethane spray foam sealant, and modified polymer sealant. These contained a variety of chemical components with an impact on health, including organotin catalyst, phthalates, halogenated flame retardant, and isocyanates.
The Environmental Protection Agency also has raised health concerns about spray polyurethane foam and suggests that people with a history of skin conditions, respiratory allergies, or asthma may want to consider alternatives.
How do you know what you’re buying?
The report discusses the potential health consequences of using building products that contain certain chemicals. But the authors acknowledge that it’s not always easy for consumers to know exactly what they are buying.
“Even as we seek safer alternatives to harmful chemicals in building products, we at the same time need content transparency so that we can know what chemicals comprise a given product,” the report says. “Unfortunately, chemical transparency has been difficult to secure. Manufacturers often cite proprietary concerns, face complex supply chains, or simply fail to recognize the need to disclose detailed material information.”
When a number of similar products are on the market, it’s easier to gather information about what’s in them. But it’s more difficult to evaluate a single, “one-off” product when the contents are not fully disclosed. As a result, the report could not recommend some promising products, such as non-isocyanate one-part spray foams.
The authors suggested that the industry take a number of steps, such as urging manufacturers to be more transparent about what goes into their products. Builders also should support the development of healthier products so they get to market as soon as possible, and get involved in industry-wide discussions about the problem.
Once manufacturers see a demand, the authors note, they develop new products that can meet both health and energy performance criteria.
This post was updated with a new photograph on Jan. 3, 2018.