How You Can Choose Non Toxic Engineered Hardwood Flooring

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Non Toxic Engineered Hardwood Flooring

How Can We Select Non Toxic Engineered Hardwood Flooring?

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My husband and I have finally decided on our engineered hardwood flooring. We are installing a hardwood flooring using a contractor.  When you are deciding on engineered hardwood flooring planks, it could be overwhelming since there are many different colors, textures, grain patterns to choose from.  Engineered hardwood flooring can emit volatile organic compounds (VOCs) into the air where we breathe in. Volatile organic compounds can be harmful to our health and it should be avoided. However, a contractor doesn’t necessarily tell you which engineered hardwood flooring is non toxic. Also, a sales person in the showroom may just give you a price range and different styles of planks, and expect you to pick a plank. I am not sure with other people but at least in my experience, I felt I had to research engineered hardwood flooring further myself to see if the particular engineered wood was non toxic. I wanted to share with you about my findings. In this post, I will talk about how engineered hardwood flooring can be toxic, what to look for when selecting engineered hardwood and what non toxic engineered hardwood flooring options are available.



How Engineered Hardwood Can Be Toxic And What To Look For

Engineered hardwood flooring can emit VOCs from engineered hardwood planks, finish and glue used in the installation. Volatile organic compounds are organic compounds that easily become vapors or gasses at a normal room temperature. They are released from products and we can be exposed by inhaling or by skin contact. Short term exposure to volatile organic compounds can cause irritation of the eyes, nose, and respiratory tract, headaches and memory problems. Long term exposure can cause damage to the liver, kidneys, and central nervous system or cancer. 

It is really hard for us consumers to measure how much VOCs are emitted from engineered hardwood flooring ourselves. However, we can find out what part of the flooring can emit harmful VOCs and try to eliminate what releases VOCs. Let’s take a look at how engineered hardwood flooring can emit volatile organic compounds. 



Engineered Hardwood Planks


1.1 How Engineered Hardwood Flooring Planks Can Be Toxic

Environmental Working Group (EWG) warns about composite wood products including engineered hardwood since composite wood products can contain glue that is made with formaldehyde, a known human carcinogen and serious home air pollutant. Any engineered hardwood made with urea formaldehyde glue should be avoided since it can emit 90 percent more formaldehyde than engineered wood containing phenol formaldehyde glue. Although plywood used in engineered hardwood floors are commonly manufactured using a phenol-formaldehyde resins these days, phenol-formaldehyde resins still contains formaldehyde and emits formaldehyde ten times more than solid hardwood. Engineered hardwood with phenol-formaldehyde resins can still emit some level of formaldehyde. Therefore, it is a good idea to check if the engineered hardwood is emitting formaldehyde at safe levels.



1.2 What To Look For In Engineered Hardwood Flooring Planks

These certifications can help you find engineered wood that emits low volatile organic compounds. (VOCs) Some certification only applies to low formaldehyde emission which is one of the main toxic VOCs from composite wood products.


Forest Stewardship Council (FSC) certification 

Although engineered wood is not entirely solid wood, the top layer is made of hardwood. Some engineered flooring have a hardwood part that is FSC certified which indicates hardwood is sustainably harvested. 

California Air Resources Board’s Phase 2 (CARB 2)

If an engineered wood plank has a CARB 2 label, that means it has composite wood core that has low level of formaldehyde emission and it is CARB 2 compliant. Carb 2 limits formaldehyde emission at 0.05 ppm. However, CARB 2 applies to only composite wood products that is sold or supplied to California. Also, some engineered wood such as 3-ply core engineered wood is not subject to CARB 2 requirements. Therefore, just because an engineered wood doesn’t have this label, it doesn’t mean it has high formaldehyde emission. However, if it has this label, it is a good indication that composite core has low formaldehyde emission.

TSCA Title V 

If you also purchase engineered wood (containing composite wood) manufactured or imported after Mar 22, 2019, it has to be TSCA Title VI or CARB 2 certified for low formaldehyde emission. (set at 0.05 ppm) United States Environmental Protection Agency (EPA) doesn’t require a TSCA compliant label if the product has a small amount of composite wood under 144 square inches. Therefore, some composite wood core engineered hardwood may not have this label. Again, if the engineered wood doesn’t have composite core, this regulation wouldn’t apply. 

CA Section 01350 

This is a voluntary certification. It tests for emissions from thousands of other chemicals in addition to formaldehyde for the whole flooring and for all types of floors. For engineered hardwood flooring products that are not subject to CARB 2 or TSCA Title V can show not only they are certified for low formaldehyde emission but other harmful VOCs.

GREENGUARD GOLD Certification 

GreenGuard is also a voluntary certification that tests emission levels for over 360 volatile organic compounds (VOCs), plus a limit on the total of all chemical emissions combined (TVOC). Some engineered wood is GreenGuard Gold certified which has stricter standards and considers safety factors to account for sensitive individuals (such as children and the elderly).


FloorScore is a voluntary indoor air quality certification for finished flooring products. A finished flooring product is tested for 35 individual VOC emissions including formaldehyde.

Leadership in Energy and Environmental Design (LEED) 

LEED provides a certification for green buildings. Engineered wood can get LEED credits under different categories. One of the categories is low emitting materials under Indoor Environmental Quality category to be qualified for LEED certification. Not all products that are LEED qualified are non toxic or have low volatile compounds (VOCs) since there are other categories that doesn’t measure indoor air quality. Engineered hardwood that fall under low emitting materials will have low VOC emission.

No Added Formaldehyde (NAF) or Ultra-Low-Emitting Formaldehyde (ULEF)

Engineered hardwood flooring that uses No Added Formaldehyde (NAF) or Ultra-Low-Emitting Formaldehyde resins and adhesives have little to no formaldehyde emissions. They can be CARB Phase 2 exempt since they have really low formaldehyde emission that is below Phase 2 emission standards. No Added Formaldehyde (NAF) or Ultra-Low Emitting Formaldehyde (ULEF) can also contribute to LEED Credit (Indoor Air Quality).

No Urea Added Formaldehyde (NUAF)

Materials that are labeled as NAUF (no added urea formaldehyde) do not use a toxic urea formaldehyde adhesives but use phenol formaldehyde as an adhesive. NAUF products meet CARB Phase II compliance and have the low emissions level. No Urea Added Formaldehyde (NAUF) can also contribute to LEED Credit (Indoor Air Quality).



1.3 Non Toxic Engineered Hardwood Flooring Planks

These are some examples of non toxic engineered hardwood flooring brands.

Mohawk Flooring – Mohawk Flooring offers flooring using PureBond Technology. PureBondTechnology does not use Urea Formaldehyde adhesives in their engineered hardwood.  Their products meets CARB requirements and can earn LEED points.

Hallmark Floors – Hallmark Floors is TSCA Title VI Compliant. Hallmark Floors has formaldehyde emission of 0.01-0.04 ppm which is lower than CARB II or TSCA Title VI limit at 0.05.

Shaw Floors – Their engineered wood meets CARB 2 requirements. Also their floors are Greenguard certified.

Uptown Floors – Uptown hardwoods exceed levels of 0.05 PPM with a testing result of 0.01 PPM (lower) in CARB2 compliance.

AAYERS Flooring – AAYERS Flooring products meet CARB 2 requirements. Their products have been tested to have formaldehyde emission of 0.01-0.02 ppm.

Twelve Oaks – Most of their engineered products are FloorScore certified and CARB 2 compliant.

Kenwood Floors – Kentwood Floors are CA Section 01350 compliant. 

Tesoro Wood – Their engineered floors are FloorScore certified which means they comply with the volatile organic compound emissions criteria of the California Section 01350 standard, or CARB (California Air Resources Board).

Harris Wood – Harris wood floors use 100% natural real hardwood 5-ply engineered flooring and no composites. Their products are CARB 93120 ULEF Compliant – the strictest U.S. guidelines for formaldehyde emissions, and additionally are manufactured using ULEF adhesives. Their products are FloorScore certified. 

Mannington – Mannington Engineered Hardwood floors are FlooreScore certified and are also CARB 2 compliant.

Kahrs  Kahrs wood floors have no added formaldehyde glue in their engineered products. They have also been the leader of sustainable flooring. 

Teragren Bamboo – All Teragren flooring products comply with California standard 01350 for indoor air quality and are CARB Phase II compliant – emitting significantly less formaldehyde than allowed by the CARB standard. Their products are also FloorScore Certified. 



Wood Floor Finishes


2.1  How Wood Floor Finishes Can Be Toxic

Hardwood is given a finish to protect the wood from scratches or damages. Many wood flooring finishes contain and release volatile organic compounds (VOCs) which can be harmful to our health. According to a Underwriters Laboratories (UL) research on wood floor finishes, researchers found that 80 percent of today’s wood finishes emit some level of toxic VOCs. Traditional solvent-based floor coatings off-gas over 60 chemicals, including some linked to cancer and reproductive harm. The study also included testing of traditional water-based coatings, water-based finish that use water as the primary solvent along with water-compatible solvents, such as n-methylpyrrolidone (NMP). NMP can cause congenital disabilities and miscarriage. The study used UL’s GREENGUARD and GREENGUARD Gold standards for VOC exposure limits. Emission levels were measured during the period of up to two weeks after the application of wood coating products. (Consumers may occupy the living space within two week period after a finish is dried and cured.) According to the study, both traditional solvent-based and traditional water-based floor coatings emitted VOCs exceeding their safe levels during this period. “Clean” water-based coatings did not exceed permissible total VOCs (TVOCs) as prescribed under UL’s GREENGUARD and GREENGUARD Gold standards. 

Then how much VOCs do wood floor finishes contain? The higher VOC content, the more VOCs will be released.  Conversion varnish or varnish finishes have VOC levels within the limit of 725g/L. US have VOC restrictions and the use of some of these varnishes are not allowed due to high VOCs. Federal law requires varnishes to contain less than 450g/L. Many states have a limit of 350 g/L, and California’s limit is 275 g/L. Oil-based polyurethane finishes commonly contain about >275 up to 550 g/L of VOCs. Water-based polyurethane finishes’ VOC levels vary up to 450 g/L.  Some low VOC water-based floor finishes contain around 50 to 250 grams of VOCs per liter. Natural oils and hardwax oils usually contain 0 g/L VOCs. Natural oils, hardwax oils and low VOC water-based polyurethane finishes will be a better choice when it comes to lower volatile organic compounds. (VOCs) 



2.2  Things To Look For In Stains and Finishes

When you choose engineered hardwood flooring, you can choose between unfinished or pre-finished engineered hardwood. For unfinished hardwood flooring, a finish is given to engineered hardwood on-site after installation. Pre-finished hardwood flooring, on the other hand, will not require any finish done on site since it is already finished at the factory. Non toxic finish options for engineered hardwood flooring is as follows.


Selecting unfinished engineered hardwood then apply low VOC water-based polyurethane finish, natural oil sealer or shellac

A  finish will off-gas volatile organic compounds while it is applied to the engineered hardwood floor, dried and cured. Volatile Organic Compounds is actually emitted the most during this time which can be very harmful for our health. Therefore, finishes that release a lot of VOCs such as oil-based polyurethane, acid cured, moisture cured finishes are not non toxic options.  Natural oil sealers or shellacs are the most non toxic finish option since they contain and release no or very low VOCs. However, keep in mind they are less durable than water-based polyurethane and will require more maintenance.  You can read more about different type of finishes (#4) in my other post and decide which finish option may be better for your situation.


Selecting pre-finished engineered hardwood with natural oil sealer or polyurethane 

If you want to avoid large off-gassing of VOCs on-site, you can choose pre-finished engineered hardwood. Pre-finished engineered hardwood is already sanded and finished at the factory so it can be just installed before you can walk on it. On-site finish process is not needed. Therefore, it doesn’t require any time for a finish to be applied, dried and cured.  Pre-finished engineered hardwood with a natural oil sealer will be one of the most non toxic pre-finish option. There are not that many pre-finished solid hardwood with a natural oil finish available. However, you can find more of natural oil finished engineered hardwood in the market. Therefore, if you like a natural oil sealer as your finish option, it is easier to find with engineered hardwood. A natural oil finish is non toxic but it is less durable than a polyurethane finish and it will require more maintenance. However, it can be easily repaired or refinished even partially.

You can also choose  a pre-finished engineered hardwood plank with a polyurethane finish. Many polyurethane finish has aluminum oxide coatings.  Factory pre-finished polyurethane finish with aluminum oxide is very durable and most engineered hardwood flooring with this finish comes with 25-35 years of warranty on residential wear. However, unlike natural oil sealer, often, aluminum oxide finish may not be repaired partially. Pre-finished engineered hardwood has a very thick coat of factory applied aluminum oxide. When being refinished, that thick coat will have be all sanded off first before a refinish is applied. Therefore, sanding only a part of the floor may not be possible since only that plank will appear look lower than the rest of the planks. Sanding of entire section or flooring may be needed.   When the floor with aluminum oxide goes through a sanding process, aluminum oxide particles can be released. Inhaling aluminum oxide particles, especially nano-sized aluminum oxide particles can be very harmful to our health.  If sanding is not a good option for the floor with aluminum oxide, a replacement of the floor may be needed. Polyurethane finish with aluminum oxide is very durable. Therefore, you may not experience damages and have a need to replace the flooring for a long time. However, damages can happen.  Therefore, decide which option you are more comfortable with when choosing a non toxic finish option.

Check out pre-finished engineered hardwood flooring



2.3  Non Toxic Wood Floor Finishes – Zero-VOC or Low VOC Finishes

The most non toxic finish option would be no VOC products such as natural oils and natural waxes.  Zero VOC finish contains no more than 5 grams of VOC’s per litre by volume. Low VOC means stains with no more than 200 grams/ litre by volume and varnishes within 300 grams/ litre by volume. Here are some zero and low VOC finishes. 

Rubio’s Monocoat Oil Plus 2C – Rubio’s Monocoat Oil Plus 2C has 0% VOC.  It does not contain any water or solvents. It has very fast curing time: 80% in 2 days. It Comes in 40 Colors

AFM Safecoat Polyureseal BP Finish – AFM Safecoat Polyurethane BP Finish has very low odor, and very low VOC. It is water-based and SCS certified as well as LEED certified. 

Bona  ClassicSeal – Bona ClassicSeal is a clear waterborne sealer that prevents the finish from penetrating into the wood surface. It is VOC compliant and virtually odorless. It is GREENGUARD Indoor Air Quality Certified.

Bona Traffic Anti Slip Satin Wood Floor Finish – Bona Traffic Anti Slip Satin Wood Floor Finish is VOC compliant and GREENGUARD Indoor Air Quality Certified.

Vermont Natural Coatings PolyWhey Floor Finish – Vermont Natural Coatings Polywhey Floor finish is made from renewable resource and has less than 180 g/l VOC (low VOC). It has very low order and dry time of under 2 hours.  It is easy to cleanup with soap and water.

Real Milk Paint Pure Tung Oil – Real Milk Paint Pure Tung Oil has zero VOCs and is FDA approved for food contact.

OSMO Polyx Hard Wax Oil – OSMO Polyx Hard Wax Oil is made of sunflower oil, soybean oil, thissle oil, carnauba wax, and candelilla wax. It has clear stain matt finish.


If you wan to avoid finish off-gassing on -site, you can choose pre-finished engineered hardwood flooring. Many pre-finished engineered hardwood flooring planks have urethane finish or urethane finish with aluminum oxide (often UV-cured).

Check out pre-finished engineered hardwood flooring



Wood Floor Installation


3.1  How Wood Floor Installation Can Be Toxic

Flooring adhesive is applied to attach engineered hardwood planks to the subfloor or underlayment when installing engineered hardwood flooring. Glue can also contain and emit volatile organic compounds (VOCs).  Urethane adhesives are widely used for engineered hardwood flooring. It contains no water and reacts & solidifies in the presence of moisture. When urethane adhesive contains solvent and other VOC contents, it will emit VOCs when applied and as it solidifies. It can also release VOCs after it dries. Acrylic based adhesives are often water-based formulated. Which glue can be used for installation depends on condition of the subfloor, requirements and recommendations of engineered hardwood manufacturer. Some manufacturers may require certain glue to be used for their engineered hardwood. Each glue comes with differing levels of VOCs. Higher VOC contents will emit more VOCs into the air.  Current VOC level limit is 100 (g/L) for wood flooring adhesives. Some urethane adhesives contain no solvent or VOCs and same as acrylic based adhesives. Whichever glue is used, if an adhesive contains solvent or high levels of VOCs, it will release VOCs.



3.2  What To Look For In Wood Floor Installation

Engineered hardwood flooring can be installed in several ways. It can be nailed, stapled, glued down to the subfloor, or floated on the subfloor. However, each engineered hardwood plank comes with different installation requirements depending on its style. Not all engineered hardwood can be nailed, stapled, glued, and floated. Therefore, find out how the engineered hardwood of your choice can be installed.

Glue used for installation can also contain volatile organic compounds (VOCs). Therefore, if you can eliminate glue as much as possible, that would be ideal. You can minimize glue by nailing down the engineered hardwood. However, engineered hardwood can not be installed over concrete directly. If you have a concrete floor, you can place a plywood subfloor first. Then, nailing or stapling down can be done on that plywood subfloor. However, some people may not want to go though a trouble installing a plywood subfloor first which requires extra labor and costs. Also, plywood is still a composite wood material. Therefore, I don’t know if I want to install plywood first just to use a nailing or stapling method.

Engineered hardwood flooring can also be glued down. This installation method will use glue on the entire floor. This will create more exposure to glue.

Engineered hardwood can also be installed using a floating method. Most of engineered flooring can be floated.  A floating floor is not nailed down to the subfloor but the edges of each plank gets attached to each other by glue and floated over the subfloor. It can be floated on concrete or plywood. Most popular styles of engineered hardwood is tongue and groove or click lock. For tongue and groove engineered hardwood, glue is applied to the tongue and groove seams (edges) of each plank to keep the planks together. Some engineered hardwood flooring products have a click lock design. A click lock design does not require glue for a floating installation since you can join the edges by clicking and locking the edges together. I like the floating method since you will use less glue than applying glue on the entire floor. Check to see if your flooring is designed for a floating floor installation.



3.3  Non Toxic Wood Floor Installation Glue

Depending on the engineered hardwood, glue may be needed for installation. If you have a contractor or a floor installer installing the flooring using glue, you may want to find out what kind of glue they are using.  Here are some non toxic glues that can be used for installation.


Robert’s 1406 tongue and groove adhesive – Robert’s tongue and groove adhesive is a solvent free, zero VOC calculated, non-flammable, non-toxic, premium water-based product.

Bostik’s TKO Urethane Hardwood Adhesive – Bostik’s TKO Urethane Hardwood Adhesive has zero VOC’s.

Bostik’s GreenForce® Advanced Tri-Linking™ Adhesive – Bostik’s GreenForce® Advanced Tri-Linking™ Adhesive has zero VOC content (as calculated per SCAQMD Rule 1168)

Bona R851 – Bona R851 is solvent and Isocyanate free with zero VOC’s. It is GreenGuard Certified and meets criteria for LEED EQc 4.1 (v. 2.1, 2.2, 3.0)

SikaBond®-T21 -SikaBond®-T21 has low VOC of 57 g/L (measured per SCAQMD rule 1168)



Final Thoughts

There are a lot to think about when choosing an engineered hardwood flooring.  You not only want to select a flooring that is non toxic but also a flooring that meets your requirements of durability, easiness of repairs & maintenance, price and style. You will have to see which options may be more suitable for your home and yourself. If you are using a contractor installing a new floor, you may not be necessarily given all the information about the project. You will have to ask and find out what glue will be used or what installation method will be used for example. However, it is better to ask and discuss with your contractor if you want to be sure what is being installed in your home. After all, you will be living with your floor for a long time.



If you would like to find out about non toxic wood flooring options, please read my post, ‘Non Toxic Wood Flooring For Your Home – Which Wood Flooring Is Non Toxic?

If you would like to find out more about non toxic solid wood flooring, please read my next post, ‘How You Can Choose The Most Non Toxic Solid Hardwood Flooring.’

If you would like to find more about ceramic or porcelain tile flooring, please read my post, ‘Ceramic or Porcelain Tile Flooring – Things to Consider When Choosing Ceramic or Porcelain Tile.’

If you are interested in non toxic mattresses, please read my post ‘Non Toxic Mattress Guide – Chemical-Free, Organic Mattress‘.

For non toxic sofa companies that you can shop from, please read my next post, ‘Non Toxic Sofa Guide – Which Sofa Brand Is Non Toxic?

For non toxic area rugs, please read my post, ‘Non Toxic Rugs – What Non Toxic, Natural Rugs Are Best?






  • go_new_mommy

    Isabelle has been an entrepreneur for last 16 years in retail and educational industry. She is also a mom. She is a mom entrepreneur who is always trying to find a better, easier way to run her business. She also tries to provide organic and non-toxic living environment for her child. She likes to research for the most non-toxic products or safe alternatives and share them with parents. In addition, she is against animal testing and supports cruelty-free products.


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