The Red List


The LBC Red List is a list of chemicals representing the “worst in class” substances prevalent in the building industry that pose serious risks to human health and the environment. The Red List is organized by chemical class and lists individual chemicals by Chemical Abstract Registry Number (CASRN). Since its inception in 2006, the Red List has been an intuitive tool for communicating the need to stop using chemicals that cause harm.

Chemical classes are added to or retired from the Red List with each new version of the LBC Standard. The chemical classes are described below.

The chemicals included in each class are detailed in the 2024 LBC Red List CASRN Guide. Individual chemicals within chemical classes are updated in the CASRN Guide on an annual basis with input from ILFI’s Material Health Technical Advisory Group.

Red List chemicals serve many different functions in many building products. However, the use of these chemicals can cause harm to health and the environment. Hazards include cancer, reproductive toxicity, acute or chronic organ toxicity, endocrine disruption, persistence, ozone depletion, and others. 

Safer chemical alternatives, product designs, and building designs are possible: although prevalent, Red List compounds are not necessary in most instances.


The LBC Watch List and the LBC Priority List create a transparent on-ramp for the LBC Red List. The 2024 LBC Red List CASRN Guide contains these lists. 

Adding chemicals or chemical classes to the  LBC Watch List signals that ILFI is considering their future inclusion in the LBC Red List. The Watch List does not impact a product’s Declaration Status, nor the ability of LBC project teams to use products that contain these chemicals. 

Substances on the Watch List may graduate to the Priority List  if ILFI intends to add them to the Red List in the near future. A chemical must be designated as “Priority” for at least 12 months before it can be added to the Red List. A chemical designated as Priority for Red List Inclusion will flag in light orange on a Declare label, but does not impact the product’s Declaration Status.

Stakeholder dialogue about whether and how to move substances between the Watch, Priority, and Red Lists is welcome. Questions and comments about specific chemicals and classes can be sent to Other ways to engage include applying to our Material Health Technical Advisory Group – email 


In 2024, ILFI performed a quality control update of the Red, Priority, and Watch Lists in order to improve the accuracy and comprehensiveness of the existing chemical classes and to align with the latest building materials research. ILFI worked with the Healthy Building Network and the Red List Working Group within our Material Health Technical Advisory Group to generate and review the changes to the Lists.  

The five types of changes to the Red, Priority, and Watch Lists in 2024 include:

  • Improving Accuracy: Correcting inaccurate CASRNs and removing duplicates. 
  • Advancing Chemicals of Concern: Moving all chemicals except antimicrobials from the Priority to the Red List (917 CASRNs), and moving all chemicals except antimicrobials and siloxanes from the Watch to the Priority List (3,198 CASRNs).
    • ILFI will do further research including alignment with industry partners on the class definition of antimicrobials before considering moving them to the Red List.
  • Updating Existing Chemical Classes: Adding chemicals to the Priority List that are already a part of existing chemical classes in Pharos (3,479 CASRNs). 
  • New Chemical Classes: Adding four new chemical classes to the Watch List — these additions indicate that ILFI is researching these chemical classes and will consider adding them to the Red List in the future, along with essential use or market exceptions as appropriate. Safer alternatives exist for some, but not all, functions in products.
    • Short-Chain Halogenated Hydrocarbons: Examples of chemicals in this class include vinyl chloride (the precursor to polyvinyl chloride), refrigerant fluids with high global warming potential, and many ozone-depleting chemicals.
    • Asphalt: An occupational carcinogen commonly used in insulation facing, waterproofing, and roofing as well as paving.
    • Stoddard Solvent: An occupational carcinogen and mutagen commonly used in roofing, waterproofing, sealants, metal coatings, paints, paint thinners. 
    • Isocyanates: Respiratory sensitizers used in spray foam insulation, spray foam roofing, and polyurethane adhesive. 
  • Removal of one Resin from the Red List: Research by a toxicology firm showed that a specific Novolac resin, a phenol-formaldehyde polymer, is formulated such that the formaldehyde is the limiting reagent and is fully incorporated into the polymer with no residual formaldehyde in the final product. This chemical is moving to the Watch List. 

Research and engagement with technical advisors and the scientific and manufacturing communities are needed before advancing more chemicals from the Priority List to the Red List or advancing the new chemical classes from the Watch List to the Priority or Red Lists.

Please review the following resources for additional information regarding ILFI’s decision and guidance for program compliance.


An active Declare label with a status of LBC Red List Free or LBC Red List Approved at the time of specification (when the project team places the product order with the manufacturer) is sufficient documentation of product compliance with I13 Red List. This remains true even if a constituent chemical in the product is added to the Red List prior to the label’s expiration date. ILFI will encourage project teams to download the Declare label information at the time of specification.

Products in Declare will be evaluated against the LBC Red List version that is active when a manufacturer submits the product for its annual label renewal. At that time, a product with a Declare status of LBC Red List Free or LBC Red List Approved may subsequently receive Declared status because a constituent chemical was subsequently added to the Red List and the product formulation wasn’t changed. ILFI will inform project teams that if they did not document the compliance status of the Declare label at the time of specification, they may cross-reference the Red List ingredient identified on the renewed Declare label with the contents of the Red List at the time of project registration, to demonstrate compliance.


Alkylphenols are a large family of organic compounds used in a wide variety of products, including cleaning products, beauty products, contraceptives, coatings, fragrances, thermoplastics, carbonless copy paper, and agrochemicals. Most concerns are focused on alkylphenol ethoxylates (APEs), which bioaccumulate and have been shown to cause endocrine disruption in fish. APEs are in cleaning products that end up in waterways from wastewater treatment effluent. Some alkylphenols, especially nonylphenol, are being phased out in Europe, and more research into their impacts is needed. A few governments with environmentally preferable purchasing programs restrict or ban APEs


Antimicrobials are a class of chemicals designed to kill or inhibit the growth of microbes. Antimicrobials are frequently used in soaps and building materials, including countertops, paints, and doorknobs. Nineteen antimicrobials were banned in soaps and bodywashes by the FDA in 2016. Antimicrobials used in building materials are regulated by the EPA as a pesticide, falling outside of the scope of the FDA’s ban. Antimicrobials are often used as a preservative in building materials, but the health benefits of their use have not been established or substantiated. Some antimicrobials are endocrine disruptors, and have been shown to impair learning and weaken muscle function.

Interest in building products with applied antimicrobial treatments has increased significantly during the recent global COVID-19 pandemic. While information regarding individual substances’ efficacy in controlling propagation of SARS-CoV-2 remains incomplete, “no evidence yet exists to demonstrate that products intended for use in interior spaces that incorporate antimicrobial additives result in healthier populations.” (COVID-19 Statement: Understanding Antimicrobial Ingredients in Building Materials, Perkins and Will and Healthy Building Network (2020)) ILFI continues to monitor the situation and commits to presenting current information about reported or potential human and environmental health impacts of antimicrobial substances as commonly used within the building industry and supporting its community of users in best utilizing this information in their own practice.


Asbestos is a mineral fiber that is used in a variety of construction materials for its strength and heat resisting capabilities. It is often found in wall insulation, vinyl floor coverings, paint compounds, roofing, heat-resistant fabrics, and automobile brakes. Exposure occurs as asbestos fibers are released into the air during use, demolition, work, building, or repair of asbestos-containing materials. Asbestos is a known human carcinogen, increasing risks of lung cancer, mesothelioma, and asbestosis.


Bisphenol A (BPA) and chemicals with structural or functional similarity, or BPA structural analogues (NTP 2017), are used to manufacture polycarbonate plastics, epoxy resins and other products. The plastics are used in many consumer products, such as drink bottles, DVDs, eyeglass lenses, electronics, car parts, and other products that must not break easily. Epoxy resins are used for lining food cans and water pipes, and for many sales receipts. Most recent testing in animal models and epidemiological studies in humans have shown that early life BPA exposure adversely effect neurological function and development, as well as adversely affect male sex organs (such as the prostate gland) in fetuses, infants, and small children (Inadera 2015). Most health organizations advise against the use of BPA for baby bottles and related infant products. BPA has also been found in breast milk demonstrating that this chemical has the potential to expose infant populations. BPA structural analogues such as Bisphenol S (BPS) are often less legally restricted and considered a “regrettable substitution” for BPA and pose many of the same risks as BPA.


California-banned solvents herein refer to the volatile organic compounds (VOCs) designated as Group II Exempt Compounds by South Coast Air Quality Management District (South Coast AQMD) Rule 102. This designation results from the US EPA’s use of the criterion of smog formation (defined as an organic compound’s contribution to the formation of ground-level ozone) to inform the regulatory definition of a VOC. As a result, US federal air quality regulations focus on VOCs that increase ground-level ozone concentrations, and exempt (meaning exclude) compounds with negligible reactivity. The basis of this determination is the ground-level ozone forming potential of ethane. Rules promulgated by South Coast AQMD (including Rule 1113 – Architectural Coatings, Rule 1143 – Consumer Paint Thinners and Multi-Purpose Solvents, and Rule 1168 – Adhesive and Sealant Applications) therefore serve as gap-filling measures, limiting exempt compounds’ product concentration and content by regulation when they are not regulated by the EPA. Additionally following these Rules that limit the percentage by weight of these exempt compounds in their respective product types, cyclic, branched, or linear, volatile completely methylated siloxanes (VMS) are not subject to the percentage by weight limit and are not included in the LBC Red List. Though the South Coast AQMD is an authority having jurisdiction (AHJ) overseeing specific sectors of the California building products market, its restrictions on VOCs are considered industry exemplars and have influenced a significant proportion of these product industries to conform to its standards.


PVC’s vinyl chloride monomer building block is a known human carcinogen, according to the US Department of Health and Human Services. In addition, PVC is a Persistent Organic Pollutant Source Material. Due to its chlorine content, PVC often contains other Red List ingredients, such as cadmium, lead, and phthalates. The manufacture and disposal of chlorinated polymers can result in the production of dioxins and disposal phases. Dioxins are some of the most potent toxins known to humans, with no known safe limit for exposure and a strong propensity for bioaccumulation. In addition, dioxins are highly persistent in the environment.

Chloroprene is a Persistent Organic Pollutant Source Material. Due to its carbon- chlorine base, chloroprene contributes to the creation of dioxins at different points in its life cycle (often manufacturing and/or disposal). According to the World Health Organization, dioxins are some of the most potent toxins known to humans, with no known safe limit for exposure and a strong propensity for bioaccumulation. In addition, dioxins are highly persistent in the environment.

Chlorinated Polyethylene (CPE) and Chlorosulfonated Polyethylene (CSPE) are Persistent Organic Pollutant Source Materials: due to their carbon-chlorine bases, these products contribute to the creation of dioxins and furans at different points in their life cycle (often manufacturing and/or disposal). According to the World Health Organization, dioxins are some of the most potent toxins known to humans, with no known safe limit for exposure and a strong propensity for bioaccumulation. In addition, dioxins are highly persistent in the environment. Similarly, furans accumulate in animal fat, concentrating as they travel up the food chain. Non-chlorinated polyethylene products are readily available in many product categories.


Chlorobenzene is used primarily as a solvent, a degreaser for auto parts, and a chemical intermediary for making other chemicals, so exposures are primarily a risk to workers making or using it. Most exposures are through inhalation of fumes. Short-term exposure can cause headaches, sleepiness, nausea, numbness, muscle spasms, and in extreme cases, unconsciousness. Chronic (long-term) exposure can cause increased signs of neurotoxicity (numbness, etc.) and irritation of the upper respiratory tract. In animals, chronic exposure has also caused kidney and liver damage. Chlorobenzene is broken down by sun and bacteria in the environment and does not accumulate in the food chain.


According to US EPA, the depletion of the Earth’s protective ozone layer by chlorofluorocarbons (or CFCs) is responsible for an increased incidence of skin cancer, cataracts, impairment of human immune systems, and damage to wildlife. CFCs have been banned from production in the United States since 1995.

Hydrochlorofluorocarbons (HCFCs) are potent ozone-depleting compounds. While less destructive than the now-banned chlorofluorocarbons, HCFCs are targeted for gradual phaseout by the US EPA, with a total ban going into effect in the year 2030. According to US EPA, the depletion of the Earth’s protective ozone layer is responsible for an increased incidence of skin cancer, cataracts, impairment of human immune systems, and damage to wildlife.


Formaldehyde is classified by the International Agency for Research on Cancer and the State of California as a known human carcinogen. Common health effects at low levels of exposure to this volatile organic compound include irritation and sensitization, and the compound also acts as an asthma trigger. Long-term exposure is associated with nasal cancers and leukemia.


Halogenated Fire Retardants (HFRs) are a broad class of flame retardants containing chlorine or bromine that have aroused concern due to their exponential accumulation in human beings in recent years. HFRs are persistent bioaccumulative toxins, meaning that they accumulate in organisms and the broader environment, often reaching alarmingly high concentrations as they travel up the food chain. In addition, certain halogenated products have shown evidence of harm to humans and other animal species. According to the Washington State Department of Ecology, for example, the toxicity endpoints of concern for Penta-PBDE include adverse effects on neurological development, reproduction, thyroid hormone disruption and possible liver toxicity.

HFRs include PBDE, TBBPA, HBCD, Deca-BDE, TCPP, TCEP, Dechlorane Plus, and other retardants with bromine or chlorine. Boron is not an HFR and is allowed. Many products, including virtually all foam insulations, contain HFRs.


Organotin compounds are a class of substances containing a bond between tin and carbon. Organotin compounds are used in the production of PVC, silicone rubber, and polyurethane. Exposure can cause memory loss, eye irritation, and liver damage. Certain organotin compounds are neurotoxins and acute exposure can be lethal. Organotin compounds are persistent in the environment and pose a threat to aquatic life at elevated concentrations. Animal studies have indicated organotin compounds might damage the immune and nervous systems.


Perfluorinated and Polyfluorinated Alkyl Substances, also commonly referred to as PFAS, are synthetic manufactured fluorine-containing chemicals that exist in many forms with many uses in building and consumer products. Perfluorinated Compounds, or PFCs, are a subset of PFAS. Building product applications of PFAS include roofing materials, paints and coatings, sealants, caulks, adhesives, carpets, and more, providing highly desirable functions such as weatherproofing, corrosion prevention, lubrication, friction reduction, and grease and water resistance. PFAS and PFCs are characterized by their carbon-fluorine bonds, which are some of the strongest bonds in all of organic chemistry. The wide range of uses for PFAS and PFCs increases the potential for human and environmental exposure and is magnified by their indefinite persistence in the environment and potential for bioaccumulation. While most individual PFAS have not been studied for their impacts to human and environmental health, their persistence contributes to bioaccumulation to levels that we know to be potentially harmful. In many cases, relatively safer non-fluorinated alternatives exist for these applications and many building product sectors are already making a transition to safer chemistries.


Mounting evidence from animal studies show the hormone-disrupting potential of phthalates, primarily orthophthalates, prompting the National Research Council to urge the US Environmental Protection Agency to pursue a “cumulative risk assessment” of this class of chemicals to determine their interactivity. Testing by the Centers for Disease Control and Prevention shows that phthalates are nearly ubiquitous in the US population, with highest concentrations in women and in children aged 6 to 11 years. The endocrine disrupting nature of phthalates has implications for childhood and reproductive development, as well as cancer incidence. The European Union and over a dozen countries have banned the use of phthalates in children’s products, as has the State of California.


PCB manufacturing in the United States stopped in 1977 but the compound is long-lasting in the environment (mostly in soils) around old manufacturing and disposal sites, in old electrical transformers and electrical devices, and in fish and their predators. PCBs make good coolants, lubricants, and insulators for electrical equipment of all kinds. They are known to cause cancer in animals and are probable human carcinogens, but exposure tends to be limited to people who worked in the electrical industry many years ago, lived close to manufacturing sites, and/or ate contaminated fish. Health effects also include acne-like skin conditions and neurobehavioral and immunological changes in children.


PAHs are a group of chemicals that are often produced by the incomplete combustion of organic material, particularly wood and fossil fuels. PAHs are commonly inhaled in tobacco smoke or smoke from indoor stoves fueled by wood or coal. They can also be ingested by eating burned meat. PAHs are also used to manufacture certain types of dyes. Exposure to PAHs is linked to lung, skin, and urinary cancer, and short-term exposure may cause vomiting and diarrhea. Almost every American has detectable levels of PAHs in their body.


SCCPs are most commonly used as lubricants and coolants in metal cutting and forming operations and are also used, along with MCCPs, as secondary plasticizers and flame retardants in plastics, such as PVC. Human exposure can be occupational, via inhalation of metalworking mists, or through contaminated food and dermal contact. Environmental exposure is usually from manufacturing activities, such as production, disposal, incineration, spills into waterways, and sewage effluent. SCCPs and MCCPs are persistent and very bioaccumulative in sediment. They have been found in marine mammals, other biota, and human breast milk in both industrial and remote areas. Toxic effects on mammals can include liver, hormone, and kidney damage that over a long term could lead to cancer in those organs.


Toxic heavy metals, including arsenic, cadmium, chromium (VI), lead (added), and mercury, pose a number of threats to health.

Arsenic is a carcinogen and can cause developmental issues.

The US Department of Health and Human Services and the International Agency for Research on Cancer have determined that cadmium is a known human carcinogen associated with lung cancer. Additionally, acute and long-term exposures can lead to lung and kidney damage, bone loss, and hypertension. In sufficient quantities, cadmium is lethal. Cadmium’s extreme toxicity means that overexposure can occur even when only trace amounts are present, such as during smelting and electroplating activities.

Chromium, primarily used in chrome plating materials, can cause breathing problems as well as nasal and lung cancer. Although chromium is a naturally occurring element and chromium III (trivalent chrome) is an essential nutrient, chromium (VI) (hexavalent chrome) can cause serious health issues, especially for factory workers who can inhale or ingest it during manufacturing. There has been concern about it in drinking water and, lacking EPA maximum allowable levels, the State of California set a public health goal for it. Chromium (VI) is used primarily for chrome plating of metals for decorative or protective finishes, making stainless steel, leather tanning, anti-corrosive agents for paints, and in textile dyes and pigments. Long-term or high-level exposure through inhalation can cause nasal irritation and ulcers, breathing problems, and nasal and lung cancer in unprotected workers. Ingestion can cause anemia and/or stomach tumors. Skin contact can cause skin ulcers and allergic reactions.

According to the Agency for Toxic Substances and Disease Registry, the environmental levels of lead have increased more than 1000-fold over the last three centuries, due almost exclusively to human activities. Lead exposure is damaging to virtually every organ and system in the human body, but is particularly damaging to the brain and central nervous system—profoundly so for young children and developing fetuses. Lead exposure is correlated with decreased IQ and delayed learning in children; scientific research has identified no safe level of lead exposure, and effects are irreversible.

According to the World Health Organization, mercury produces a suite of ill effects, including harm to the nervous, digestive, and immune systems, and even death. WHO lists children and developing fetuses as especially vulnerable to damage from mercury. Mercury bioaccumulates in the environment, eventually reaching concentrations thousands of times more intense than ambient levels.


VOCs are members of a large group of organic chemicals that can evaporate into the indoor air under normal temperature conditions and into the outdoor air, causing environmental impacts such as photochemical smog. Their health effects vary widely, from respiratory irritants to human carcinogens (such as formaldehyde), which is of concern since they are ingredients in many products in the built environment. On-site wet applied products (paints, adhesives, and sealants) are of particular concern because they can directly impact the health of installers who may not be using breathing or dermal protection, unlike in-factory wet applied materials that are (usually) applied with worker and environmental protections in place.

Unlike other items that appear on the Red List, (VOCs) are not banned outright. Wet-applied products (including coatings, adhesives, and sealants) applied on site must meet the following established emissions and/or VOC content standards: “Wet-applied products (including coatings, adhesives, and sealants) applied on site must have VOC levels below the South Coast Air Quality Management District (SCAQMD) Rule 1168 for Adhesives and Sealants or the CARB 2007 Suggested Control Measure (SCM) for Architectural Coatings, as applicable.”


Many conventional wood treatments introduce a litany of human health and environmental problems. The traits that make wood treatments effective at retarding rot and insect damage are also effective at damaging many other forms of life. According to the US Department of Health and Human Services, creosote exposure is associated with skin and scrotum cancer in humans, and liver, kidney, and gestational problems in laboratory animals. Inorganic arsenic is not only an acute toxin; it is a known human carcinogen. Pentachlorophenol is linked to liver and immune system damage in humans, and reproductive and thyroid damage in laboratory animals.



The LBC Red List has moved to an annual update process as of 2021. Previous versions of the LBC Red List along with the dates they were active can be found in the ILFI Membership Dashboard in the “Resources” tab of the Living Building Challenge section.