“The Red List” might sound like something from the Cold War. But the Red List has nothing to do with politics, and everything to do with chemistry. The Red List is actually a list of “worst-in-class” materials, chemicals, and items that the green building industry is trying to avoid. And even if you’re not a construction professional, knowing these materials and what products are made from them can help make your home and renovation projects safer and more durable.
The red list
The Red List is generated by the International Living Future Institute as part of the Living Building Challenge, a certification system that requires buildings to achieve net positivity for energy, water and waste. Updated annually, the LBC Red List encourages builders to avoid the worst materials and chemicals used in construction. Eliminating them all completely from house building may not even be possible right now. But the list provides an objective for improvement. For homeowners, the list can inform home improvement projects and guide you to safer household products. Learn more with this simplified version of the Red List.
Asbestos is a mineral that was used in thousands of products, particularly from the 1930s to the 1970s, most notably in popcorn ceilings. The United States banned asbestos in 1991, but the ban was overturned and it is still found in products ranging from insulation to vinyl tile. The tiny asbestos fibers can easily be inhaled and cause mesothelioma and other diseases. Protective gear is required when working around asbestos. It must be disposed of as hazardous waste.
Cadmium is a heavy metal associated with flu-like symptoms from acute exposure and cancer, kidney, bone and lung disease from chronic exposure. Nonetheless, cadmium can be found in cookware, home electronics, and of course batteries. Cadmium is also used in pigments which can lead to exposure through peeling paint or paint dust created during construction.
Chlorinated Polyethylene & Chlorosulfonated Polyethylene
Chlorinated polyethylene (CPE) is an inexpensive variant of polyethylene plastic, but with a chlorine content of around one-third. Like ordinary polyethylene, it is versatile, used for sheathing wires and cables, roofing, pipes and tubes, etc.
Chlorosulfonated polyethylene (CSPE) is the basic polymer of synthetic rubbers. Sold under the brand name Hypalon, it was commonly used for insulation of wires and cable sheaths. It was discontinued in 2009 due to production safety issues, lead content and the highly toxic fumes it gives off when burned.
PECs and CSPEs are sources of persistent organic pollutants and contribute to the creation of dioxins and furans at different stages of their life cycle.
Although CFCs were banned in 1987, the hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) that replaced them are still used in aerosols, refrigerators and air conditioners. HFCs are not as harmful to the ozone layer as CFCs, but the two groups of long-lived chemicals are still potent greenhouse gases. Other countries have agreed to phase out HFCs.
Chloroprene is used to make neoprene, the material best known for its use in wetsuits and fishing waders, but it is also used to waterproof roofs and seal windows. While neoprene is chemically inert, chloroprene is a carcinogen that can be inhaled and can enter the body through the skin. It is a source material of persistent organic pollutants that contributes to the creation of dioxins and furans at various stages of its life cycle, such as its manufacture in the cancer aisle of Louisiana.
Formaldehyde is a VOC and a known human carcinogen associated with nasal cancer and leukemia. It also acts as an asthma trigger and a skin irritant. It is found in insulation and manufactured building products like composite countertops, particle board and laminates. It is also found in household products like mattresses and upholstery, as well as in glues, paints, caulks, etc.
Halogenated flame retardants
Halogenated flame retardants (HFRs) are persistent, bioaccumulative toxins that adversely affect neurodevelopment and reproduction. They can cause thyroid hormone disruption and possible liver toxicity. When burned, they release dioxins and furans. They are found in insulation, foam, electronics and upholstery, including in child car seats. Although some HFRs are prohibited, in some cases they may be necessary to meet legal fire safety standards.
In the past, lead was added to gasoline and paint, which can still be present in older homes. Homes built before 1986 are more likely to have lead pipes, fittings and solder, which can get into drinking water. A toxic heavy metal, exposure to lead damages every organ and system in the human body, especially the brain and central nervous system. The impacts are most profound for young people.
Yet another highly toxic heavy metal, mercury is a bioaccumulative substance that harms the nervous, digestive and immune systems, and can even cause death at appallingly low levels of exposure. Nonetheless, it can still be found in household items, from light bulbs to thermostats, which must be disposed of carefully to avoid spills.
Phthalates are almost ubiquitous in the American population, with the highest concentrations in children aged 6 to 11 and in women. The National Research Council has urged the EPA to continue a “cumulative risk assessment” of these chemicals, which have carcinogenic and hormone-disrupting potential. In construction, phthalates are primarily used to make PVC or vinyl more flexible, supple and durable for use in roofing, adhesives and sealants, flooring and wall coverings.
Polyvinyl Chloride (PVC)
Vinyl chloride, a building block of PVC and other chlorinated polymers, is a known human carcinogen. PVC is a source material of persistent organic pollutants that often contains other Red List ingredients such as heavy metals and phthalates. Its manufacture and disposal can lead to the production of bioaccumulative dioxins. Better known as a coating material, PVC is the most widely used plastic for construction products. It is found in pipes and fittings, flooring, window and door profiles and roofing membranes.
Treatments of wood containing creosote, arsenic or pentachlorophenol
The characteristics that make conventional wood treatments effective against rot and insect damage also make them toxic. Studies link exposure to creosote with certain cancers in humans and with liver, kidney and pregnancy problems in laboratory animals. Inorganic arsenic is not just an acute toxin; it is a known human carcinogen. Studies link pentachlorophenol to liver and immune system damage in humans, and reproductive and thyroid damage in laboratory animals. Treated lumber is used most often in exterior projects, but can be used anywhere the lumber might get wet, such as when posts are buried in the ground.