Flooring Products Hazard Spectrum
Many flooring materials are manufactured with a protective topcoat, a standard practice in the industry. While some ingredients in topcoats (polyurethane or epoxy-based resin hardened with aluminum oxide and exposure to ultraviolet light) may have hazards throughout their life cycle, we have not considered their hazard contribution to the ranking of the flooring material itself because the topcoat is so prevalent across product types.
The primary health concern stemming from these coatings is for workers who would be exposed to the coating while it was wet in the factory. However, some products include nanomaterials in topcoats, and these may be a concern for residents as well. The National Institute for Standards and Technology (NIST) has raised concern that “substantial” amounts of nanomaterials in topcoats may be released via repeated mechanical forces such as walking on, mopping, and polishing floors. The federal agency is concerned that, “such release of the nanosize material is potentially harmful to the occupants, particularly children who typically experience greater exposure to substances deposited at floor level.”
Given the widespread presence of topcoats and nanomaterials in resilient and wood flooring and ceramic tiles, it is not possible for consumers to avoid them at this time. Topcoats are a high priority for disclosure and hazard avoidance through green chemistry solutions.
There are many ways consumers can help. Encourage manufacturers to fully disclose the content (including topcoats, stain-repellent treatments, and antimicrobials) and associated health hazards for flooring products through the industry’s collaborative, user-designed open standard, Health Product Declaration (HPD). In addition, there may be new, innovative flooring options that are not yet included in our hazard spectrum. Request HPDs for these products so their content can be assessed and compared to standard materials.
Here are some general rules of thumb to use when choosing flooring materials:
- Prefer non-vinyl flooring. Vinyl flooring has many life cycle concerns and also can contain many additives of concern. If possible, avoid materials that use vinyl. If you use vinyl flooring or carpet with vinyl backing, make sure it is free of hazardous phthalate plasticizers which can migrate from products and expose residents, particularly young children crawling on floors.
- Avoid fluorinated stain repellents. Per- and polyfluoroalkyl substances (PFAS) are commonly used in stain-repellent treatments for carpets. This class of chemicals is a high priority to avoid because they can be toxic, persist in the environment, and build up in body tissues. Many new carpets are becoming available without these stain repellents.
- Check the type and source of recycled content. Recycled content can add significant hazards to products if sourcing is unknown and screening is not performed. In particular, you should avoid fly ash, which is used as a filler in carpet backings, crumb rubber used in recycled rubber flooring, cathode ray tubes (CRTs) in ceramic tile, and post-consumer recycled vinyl which often contains legacy contaminants. See the hazard spectrum below for more information and resources.
- Avoid products with high hazard antimicrobial additives, like triclosan (which is a PBT and suspected endocrine disruptor), or products that are marketed as having a health benefit. Some antimicrobials may be necessary as preservatives, but these merely protect the product from degradation and do not provide a health benefit. Products marketed as being “antimicrobial” and having a health benefit may contain additional antimicrobials beyond those needed for preservation, and these products have not been shown to provide any actual health benefit. Worse, the added antimicrobials can migrate out of the products and end up in the dust of interior spaces where people can become exposed. Of particular concern are antimicrobials based on silver nanoparticles (nano-silver). These ultra-small particles are not well understood, and are able to pass through the walls of cells in the body. Products described as “antimicrobial” and claiming to have a health benefit are best avoided whenever possible. For more information on Antimicrobials, read our blog post or the full report from HBN and Perkins + Will, Healthy Environments: Understanding Antimicrobial Ingredients in Building Materials.
- Prefer products with a CDPH emission certification, but don’t rely on this information alone. Ask for products certified to the most protective, residential scenario. Many green building programs and certifications have requirements for emission testing of flooring products. These are typically based on the California Department of Public Health (CDPH) Standard Method for Testing and Evaluation of VOC Emissions. Requiring CDPH emission testing may help weed out some of the worst actors in terms of VOC emissions from floors, but it is important to keep in mind that this testing only covers a small number of volatile chemicals (the standard imposes limits on only 35 specific VOCs). Many other volatile, semi-volatile, or nonvolatile hazardous chemicals may still be found in products certified to this standard. Use the other rules of thumb and the hazard spectrum below to help avoid other chemicals of concern in flooring products.
Be aware that some linoleum flooring has optional layers for acoustic insulation or floating floor installation which can add additional hazards. Floating floors do, however, avoid the use of a potentially hazardous adhesive, so are still a preferred flooring option. See the Flooring Installation Hazard Spectrum for more information.
Pre-finished solid wood floors are a very good flooring option. Made from a single piece of wood, and purchased with a stain and topcoat already applied, this type of flooring allows for the chemically intensive finishing processes to take place in a factory where there are pollution controls and workers are protected.
If possible, find flooring that can be installed without an adhesive.
Ceramic tiles made without toxic glazes can be relatively low-impact materials for a flooring (or wall) installation. Tiles made in the USA are typically free of lead compounds in their glazes. Look for tile product literature that identifies where they’ve been made, and what they are made of, including frits, glazes, and pigments. Unglazed tiles are most preferred.
Avoid tiles with non-specific post-consumer recycled content. These contents may be old cathode ray tubes (CRTs) from TV sets and computer monitors. They contain high concentrations of lead. Tiles with CRT content are sometimes called CRT tiles.
For more information, read Made in the USA: A Healthy Choice for Ceramic Tiles
Formaldehyde-based binders emit formaldehyde (a carcinogen and asthmagen) over time. Preferring floors made with an NAUF (no added urea formaldehyde) binder at a minimum is a good practice; an NAF (no added formaldehyde) binder is even better. See our Composite Woods Hazard Spectrum for a further ranking of composite wood binders.
When possible, prefer a product that does not require an adhesive for installation.
As noted above, solid wood floors are a good flooring option, made from a single piece of wood without additional binder. When the boards are installed unfinished and require stains and topcoats to be applied within the building, those volatile and sometimes flammable chemicals can be brought into the project in an uncontrolled way, exposing installers and others nearby. Prefer pre-finished solid wood floors if possible, and look for flooring that can be installed without an adhesive.
Floors made from new rubber do not contain the highly toxic legacy contaminants often found in recycled rubber floors (see below).
However, the composition of these floors can vary widely, and manufacturers often do not disclose their contents. Further, isocyanates used in the binder that holds the rubber granules together are asthmagens.
Vinyl and polyurethane backings have significant life cycle concerns and often contain hazardous additives. Alternative backings like polyolefin are less hazardous and more readily recyclable at the end of the product’s life.
Fly ash is commonly used as a filler in carpet backing and it contains heavy metal contaminants. Alternative fillers include calcium carbonate and ground, recycled post-consumer container glass which are becoming more common and don’t contain toxic substances.
Per- and polyfluoroalkyl substances (PFAS), commonly used in stain-repellent treatments for carpet fibers, are a high priority to avoid. Alternative treatments are becoming available and appear to be better from a health standpoint, but greater transparency about their chemical identities and hazards is still needed.
Because more transparency is needed about PFAS alternatives, and additional hazardous chemicals may be found in carpets meeting the requirements of this category, it is ranked as yellow instead of green. Additional chemicals of concern that may be found in carpet include antimicrobials and flame retardants.
As noted above, engineered floors are made by pressing layers of wood together with a binder into a solid board. When the boards are installed unfinished and require stains and topcoats to be applied within the building, those volatile and sometimes flammable chemicals can be brought into the project in an uncontrolled way, exposing installers and others nearby.
Engineered floors requiring on-site finishing are not recommended. However, if this material must be used, preferring floors made with an NAUF binder (good), or NAF binder (better) can decrease exposures to formaldehyde formaldehyde (a carcinogen and asthmagen) after the installation is complete.
Note that some floors are typically sold unfinished, but can be pre-finished by the manufacturer if requested.
For more information on PVC see this joint publication between HBN and Perkins + Will.
Because of the toxic materials required to make vinyl, and the toxic pollution created when it is disposed of, vinyl floors of any kind are not a preferable material.
In addition, the inclusion of recycled vinyl in new products is a major pathway for the introduction of hazardous materials. Because vinyl products of all kinds are recycled together, hazardous lead, arsenic, PCBs, and phthalates can be found in post-consumer recycled vinyl.
For more information on the hazards of recycled vinyl, see this report by Healthy Building Network.
For more information on vinyl, see this joint publication between HBN and Perkins + Will.
Coal fly ash used as filler in carpet backings. Fly ash is a waste product from the combustion of coal and can be contaminated with mercury (a PBT developmental and reproductive toxicant) and other metals present in the coal itself.
Per- and polyfluoroalkyl substances (PFAS) used as stain-repellent treatments. Health hazard information is not available for all the chemicals within this large group, but PFAS as a class have been identified as chemicals of concern because many have been found to be highly toxic, persist in the environment, and build up in body tissues.
Vinyl and Polyurethane backings. Because of significant life cycle concerns, vinyl and polyurethane are not preferred materials. Polyurethane is based on isocyanate chemistry. Isocyanates are a leading cause of workplace asthma, so present a concern during manufacturing, and residuals may be present in the final product. Vinyl and polyurethane backings also commonly contain hazardous organotin catalysts, and vinyl backings may be plasticized with hazardous phthalates.
Carpets containing all these substances of concern are rated as red on the hazard spectrum - those that avoid them all are rated yellow, see above.
For more information on carpet content and carpet recycling, see the brief on HomeFree or the full report here, Eliminating Toxics in Carpet: Lessons for the Future of Recycling.
The inclusion of recycled vinyl in new products is a major pathway for the introduction of hazardous materials. Because vinyl products of all kinds are recycled together, hazardous lead, arsenic, toxic PCBs, and elevated levels of plasticizers can be found in post-consumer recycled vinyl.
For more information on the hazards of post-consumer recycled vinyl, see this report by Healthy Building Network.
 Unless otherwise noted, product content and health hazard information is based on research done by Healthy Building Network for Common Product profiles, reports, and blogs. Links to the appropriate resources are provided.
 Polyurethanes are based on isocyanates, which are asthmagens, and epoxies rely on chemicals like Bisphenol A (BPA) which is a developmental and reproductive toxicant and endocrine disruptor. See Common Products for Bamboo Flooring (engineered), Hardwood Flooring (prefinished), Heterogeneous Vinyl Resilient Sheet Flooring, Homogenous Rubber Sheet Flooring - Virgin Rubber, Luxury Vinyl Tile (LVT), and Linoleum Flooring and Tian, Dong, Jeffrey Ross, Susan Monroe, and Larry Leininger. Uvv curable coating compositions and method for coating flooring and other substrates with same, n.d. https://patents.google.com/patent/US20100276059A1/en.
 Lipiin Sung, Tinh Nguyen, Andrew Persily, Nanoparticle Released from Consumer Products: Flooring Nanocoatings and Interior Nanopaints Final Report to U.S. Consumer Product Safety Commission. Interagency Agreement CPSC-I-12-007. NIST Technical Note 1835. National Institute of Standards and Technology, U.S. Department of Commerce, July 15, 2014. See also: Tinh Nguyen, Lipiin Sung, Joannie Chin, Andrew Persily, Characterization of Airborne Nanoparticle Released from Consumer Products. Final Report to U.S. Consumer Product Safety Commission. Interagency Agreement CPSC-I-12-007. NIST Technical Note 1787. National Institute of Standards and Technology, U.S. Department of Commerce, August 2013.
 California Department of Public Health (CDPH) Standard Method for Testing and Evaluation of VOC Emissions (formerly called California 01350) uses a small scale chamber test to determine emission of VOCs from products. Results of the small scale testing are modeled to represent different real world scenarios. The most protective is the residential scenario, and this should be preferred if available. Most certifications now available are for the less protective school or private office scenarios. Programs that certify the CDPH Standard Method or a variation of the standard include the industry certifications, Resilient Floor Covering Institute FloorScore and Carpet & Rug Institute Green Label Plus, and independent certifications GreenGuard Gold, SCS Indoor Advantage Gold, and Berkeley Analytical Clear Chem.
 Cooper, Anderson. “Lumber Liquidators Linked to Health and Safety Violations.” 60 Minutes, March 1, 2015. https://www.cbsnews.com/news/lumber-liquidators-linked-to-health-and-safety-violations/.
 “Benefits of Resilient.” Congoleum. Accessed June 10, 2019. https://www.congoleum.com/benefits-of-resilient/.
 Tiles rated with an abrasion resistance rating of Class IV are appropriate for all residential and most commercial applications. Those with a rating of Class V are appropriate for all residential and commercial applications. “Understanding Ceramic Tile Technical Specification Charts.” Conestoga Tile, January 12, 2015. http://www.conestogatile.com/learning-center/understanding-ceramic-tile-technical-specification-charts/. and Simpson, Katelyn. “Tile Abrasion: ASTM C1027 and Possible Upcoming Changes.” TILE Magazine, October 2009. https://www.tcnatile.com/images/pdfs/Tile%20Abrasion%20-%20ASTM%20C1027%20and%20Possible%20Upcoming%20Changes.pdf.
 In addition to HBN’s report on Avoiding Contaminants in Tire-Derived Flooring linked above, see the following report for additional information on potential contaminants in crumb rubber. “Athletic Playing Fields: Choosing Safer Options for Health and the Environment.” Toxics Use Reduction Institute (TURI): UMass Lowell, April 2018. https://www.turi.org/TURI_Publications/TURI_Reports/Athletic_Playing_Fields_Choosing_Safer_Options_for_Health_and_the_Environment.
 For more information on PFAS, see the U.S. Environmental Protection Agency (EPA) website here: https://www.epa.gov/pfas/basic-information-pfas and California’s Department of Toxic Substances Control draft report on PFAS in carpet here: https://calsafer.dtsc.ca.gov/keydocument/index/?guid=20f14fc5-450f-4019-829a-ae9785b6b7f4.
 “Health Concerns about Spray Polyurethane Foam.” Overviews and Factsheets, US EPA, OCSPP, https://www.epa.gov/saferchoice/health-concerns-about-spray-polyurethane-foam.
Last updated: October 10, 2019