Appendix E: Substances of concern by functional class

The GSPI has identified six chemical classes of concern (known as the Six Classes) that contain many of the harmful chemicals found in everyday products, including building materials. The GSPI framework is unique in that it groups chemicals based on their molecular structure and/or functional uses. This function-driven approach is similar to how designers think about materials, and therefore a more relatable resource for further information. In identifying these groups, GSPI hopes to raise questions about whether these chemicals are needed at all and, if so, how they can be replaced with safer alternatives. Each class is described briefly below, summarized directly from GSPI’s website. 64

Highly Fluorinated Chemicals (HFCs) In the built environment, HFCs are often used in finish products like carpeting to provide stain- and waterresistance. Because these chemicals are inert to most natural chemical degradation processes, they do not break down and accumulate in the environment. In fact, these chemicals have been detected in humans and biota globally. In humans, they have been associated with kidney and testicular cancer, thyroid disease, decreased fertility, elevated cholesterol, and changes in hormone function. These chemicals have become the norm in many finish products, where stain- and water-repellency has become the conventional expectation. The big question is: is it essential in this context, and is it worth the potential for harm? Antimicrobials Antimicrobial chemicals are frequently used in the built environment in products such as countertops, paints, and furniture to prevent microbial growth. These compounds, which can be ingested through the skin, have been detected in most Americans. In humans, they can disrupt hormone functioning, and may cause adverse reproductive and developmental effects, and increased allergen sensitivities. Additionally, they are prevalent in the environment, which raises concerns about their potential impacts on aquatic systems. Further, there are concerns that the excessive and unnecessary application of antimicrobials promotes the growth of resistant bacteria.

Flame retardants Flame retardants are ubiquitous in the built environment. They can be found in furniture, insulation, and electronics, among many other product types. They have been detected in most Americans, with the highest levels found in children. Research has revealed associations with lower IQ and hyperactivity in children, and hormone disruption, decreased fertility, and cancer in adults. Simultaneously, additional research has shown that as currently used in furniture and building insulation, these chemicals do not improve fire safety. GSPI and BuildingGreen have compiled a summary of known alternatives to flame retardant-containing insulation products. 65

Bisphenols and phthalates Bisphenols and phthalates are found in plastics and pesticides, among other products. In the built environment, Bisphenol A (BPA) is a component of epoxy resins, which are found in high performance coatings and fluid-applied flooring, fillers, some solid-surface countertops, and sealants. Phthalates are often used as plasticizers in plastic products. They are the chemical additives used to make PVC soft in applications like electrical cable jacketing. Many bisphenols and phthalates are endocrine disrupting chemicals, with strong effects even in low concentrations, and have been detected in nearly 100 percent of tested humans. They are most harmful during critical windows of fetal development. Some solvents Solvents are used to dissolve or disperse other substances. In the built environment, solvents are used in paints, adhesives, coatings, and in the manufacturing processes for many other products. In paint, for example, a solvent would act as a carrier to allow dissolved pigments and resins to be spread. Once the paint is spread, the carrier solvent evaporates off, leaving the paint behind. These solvents, therefore, are highly volatile and, once vaporized, inhaled and absorbed by humans. Some are associated with neurotoxicity, reproductive toxicity, and carcinogenic effects during both short-term, high-level exposure and long-term, low-level exposure. It is assumed that the functional performance of these solvents relies on their high volatility; however, the availability and performance characteristics of water-based paint, coating, and adhesive products have increased in recent years.

Metallic additives In the built environment, metals of concern (such as cadmium, lead, mercury, and arsenic) are often used in pigments, coatings, electrical components, and in some cases, as antimicrobial additives in treated lumber. Many metals have the potential to bioaccumulate, and, consequently, once they migrate from products into the food chain, certain metals can bioaccumulate in humans and animals. While many metals are essential nutrients of the human diet, they can be toxic to humans in higher levels. Other metals have been found harmful to humans, even in very low concentrations. Both types of metals may interact with human biochemistry in concerning ways. Such interactions can cause a variety of nervous system disorders and cancers.