What is Formaldehyde?

Formaldehyde is a colorless gas, with a strong odor. It is a flammable gas at room temperature. Those exposed to formaldehyde may have moderate to acute health repercussions such as: irritation to the skin, nose, eyes, and throat and some exposure levels may even lead to cancer. Formaldehyde is a known carcinogen. Human exposure at concentration levels exceeding 3.0-5.0 ppm is harmful.2

Formaldehyde is commonly found in resins of composite wood products, glues, paints, lacquers and varnishes such as nail polish, dry cleaned items, some cleaning products, fertilizers/pesticides, fuel burning sources and even cigarettes. Formaldehyde is all around us. Wood naturally emits low levels of formaldehyde, therefore there is no such thing as a ‘formaldehyde free’ products, only ‘no added formaldehyde’.1


Formaldehyde is also known as : methanal, methylene oxide, oxymethylene, methylaldehyde, or oxomethane. [CASRN 50-00-0]


Different Types of Resins

Urea Formaldehyde is the most common binder used to glue the small pieces of wood together in composite wood products. It is a solid substance and is a thermosetting resin. Urea Formaldehyde is made up of urea and formaldehyde. This resin can cause asthma and skin allergies. The high alarm regarding this glue is due to that urea formaldehyde continues to cure throughout its lifetime, off-gassing for long periods after installation for the end use.2

There are alternative binders for composite wood that emit less formaldehyde in the end-use. Higher levels of humidity and moisture can cause urea formaldehyde to break down into formaldehyde gas.1


Additives such as melamine and hexamine can be added to formaldehyde which reduces emissions. These chemicals can reduce emissions by 2-10 times.1

Phenol formaldehyde is another common binder that emits 90% less formaldehyde than urea formaldehyde. However, phenol has its own health concerns associated with it such as a suspected immunotoxicant.1

Methylene diphenyl diisocyanate (MDI) is also sometimes used. The aniline in the MDI is a probable carcinogen both by the EPA and the California Proposition 65. Isocyantes (which is on the International Living Future Institute’s Chemical Red List) is a leading cause of occupational asthma.1


CARB is short for the California Air Resource Board, but is often referred to as the formaldehyde emission threshold of composite wood products (such as that of engineered wood flooring) as part of the California 93210 air regulation. CARB Phase 2 is another title that refers to CARB formaldehyde compliance. There are two phases, Phase 1 and Phase 2. As of December 31, 2013, Phase 1 is not used anymore and a Phase 2 threshold has been adopted.

Phase 1 : <0.08ppm

Phase 2 : <0.05ppm

Composite wood consists of hardwood plywood, particleboard, high density fiberboard, and medium density fiberboard. Composite wood is produced from lumber which is broken down into fibers and combined with wax and resin. This is then heated and pressured into wood panels. The resin that holds the composite wood together emits formaldehyde at normal environmental temperatures. The acronyms NAF and ULEF are the two most common labels used on engineered products: No Added Formaldehyde, and Ultra-Low Emitting Formaldehyde.

In engineered wood flooring, the core material is usually made of a composite wood such as Baltic birch plywood, poplar plywood, and eucalyptus plywood. Wood flooring materials which are not subject to CARB regulations:

  • Solid wood flooring
  • Solid cork flooring
  • Engineered wood that is made of a 3-ply solid lumber, for example PID Floors InLove Collection.


As a side note: NAUF – No Added Urea-Formaldehyde is not recognized in LEEDv4 or by CARB.


The US Environmental Protection Agency has developed a nation-wide regulation which matches its strict formaldehyde emission limits on composite wood products with Phase 2 levels. This regulation is under the Toxic Substances Control Act (TSCA) called Title VI: Formaldehyde Standards for Composite Wood Products. This regulation goes into affect December  12, 2017.

California Proposition 65

California Proposition 65 is the Safe Drinking Water and Toxic Enforcement Act and enacted to help California residents protect themselves from harmful chemicals that are known to cause cancer, and reproductive issues such as birth defects. The New California Proposition 65 will go into effect August 30th, 2018 and will include a list of 65 toxic chemicals that must be disclosed and labeled on products destined to be sold, bought, manufactured, and used in California.


1Global Health & Safety Initiative. 2008. Alternative Resin Binders for Particleboard, Medium Density Fiberboard (MDF), and Wheatboard. [accessed 2017 April 20].

2Mount Sinai. 2015. Medium Density Fiberboard: Workplace Health for Carpenters. [accessed 2017 April 20].


To the best of our knowledge, the information contained herein is accurate and reliable as of the date of publication; however, we do not assume any liability whatsoever for the accuracy and completeness of the above information.