WELL Building Standard v2 Material Overview


The WELL Materials concept aims to reduce human exposure to hazardous building material ingredients through the restriction or elimination of compounds or products known to be toxic and the promotion of safer replacements. Compounds known to be hazardous to the health of occupational workers and/or known to bioaccumulate or aggregate in the environment are also restricted and in some instances not permitted.


The chemicals industry is a central part of the global economy and is integral to a number of sectors that have played a major role in improving life expectancy and the quality of life over the past 150 years. However, the health and environmental impacts of most chemicals in circulation, despite their ubiquity, are unknown. For example, an estimated 95% of chemicals largely used in construction lack sufficient data on health impacts.[1]

As the global population grows and urban centers expand in size and number, the demand for material goods and the rate of chemical production is expected to rise. The global chemicals output grew by 54% between 2000 and 2010, with emerging economies accounting for 65% of the increase, and is expected to grow at a rate of 35% from 2012-2020.[2,3] Many of these chemicals will be used in the construction industry, one of the largest and most active sectors globally. Building materials and products are not only an integral part of our lives but, unlike most consumer goods, have a much longer use phase, making their chemical composition, and potential impact on indoor air quality, significant.

Volatile organic compounds (VOCs) comprise a large group of chemicals abundant in indoor environments due to various source materials, including insulation, paints, coatings, adhesives, furniture and furnishings, composite wood products and flooring materials.[4]  Both VOCs and semi-volatile organic compounds (SVOCs) have a wide range of health effects, from respiratory irritation to cancer.[5] Similarly, legacy chemicals are typically toxic, persistent and prone to bioaccumulation. These include lead, asbestos, mercury, chromated copper arsenate (CCA) and polychlorinated biphenyls (PCBs). Although these chemicals are largely restricted in manufacture and use, they continue to pose dangers not only in older structures but also through environmental contamination.[6-8] For example, the blood lead burden of today’s population is 500 to 1,000 times greater than our pre-industrial counterparts.[9] Today, exposure to lead accounts for approximately 0.6% of the global burden of disease.[10] Global lead contamination across soil, water and air is still a significant issue, even in countries that regulate the production and use of the heavy metal, and is especially problematic in developing countries.[9,10]

Additionally, hazardous waste that is improperly handled can be detrimental to both human health and the environment.[11] Land contamination poses significant public health concerns. The World Health Organization maintains a list of chemicals of major public health concern in relation to soils, including arsenic, asbestos, dioxin, pesticides and heavy metals (mercury, lead and cadmium). These chemicals of concern are found abundantly across the globe and are linked to various health impacts.[8] Many pesticides, in particular, pose exposure risks to vulnerable populations such as children due to the fact that they are used across various space types, both indoors and outdoors.[8,12] Wood treated with biocides can leach arsenic and preservative components into the soil where children can be exposed.[13,14] Children’s playground equipment and artificial turf can also pose dangers, as these materials wear and tear over time, forming dust or flakes containing chemicals like lead at levels that can be detrimental.[15,16]

One area of focus for advancing health through the Materials concept mandates emissions and content thresholds for building materials and products. This is particularly important for indoor air quality (IAQ) and health, especially for compounds known to be both hazardous and volatile under ambient conditions.[17] Low-hazard cleaning products, the use of effective cleaning equipment, and design and furnishing guidelines that promote efficient cleaning practices also ensure good indoor air quality.  To further mitigate environmental contamination and protect public health, WELL includes guidelines for the safe disposal and recycling of hazardous waste. Legacy chemicals must also be safely handled through protocols and best practice guidelines for abatement, in-place management and protective action during repair, renovation or demolition. The application of Integrated Pest Management (IPM) and use of low-hazard pesticides, along with signage and notice of application, further works to protect health. Soil, water and air contamination is also addressed through the testing and redevelopment of contaminated sites. Remediation of such sites removes toxic hazards and can work to support environmentally responsible growth and prevent sprawl.[18] Outdoor structures that contribute to toxic leachates and soil and air contamination are addressed through WELL, while new materials and products used outdoors must meet ingredient restrictions or thresholds. Lastly, third-party certification and labeling schemes serve to differentiate products with safer ingredients and help support consumer education and market demand for safer goods.

WELL promotes the identification, evaluation and management of hazardous ingredients across building materials, cleaning products, waste, outdoor spaces and landscaping. Through all of this, WELL aims to reduce risk of exposure, whether direct or through environmental contamination. Lastly, by enabling informed decision-making, WELL helps to bridge data gaps in the supply chain, supports innovation in green chemistry and advances market transformation.