Medium Density Fibreboard (MDF) is a composite wood product made by binding wood dust together into solid panels using a resin, that typically contains formaldehyde. In general 10% of the product is composed of the formaldehyde resin (1). It is a widely used material in construction (mainly for cabinet carcasses) and furniture manufacturing, for solid core doors, interior trims and moulding, decorative wall paneling, and laminate flooring.
Due to its composition and density, MDF off-gasses formaldehyde relatively slowly and may take years to complete the process, it emits approximately 0.11 parts per million (ppm) of formaldehyde (2), which is at the upper limit allowed by the EPA and California's CARB 2 regulations (USA). This allowance accounts for MDF's higher formaldehyde emissions compared to other engineered wood products.
Indoor Air Quality (IAQ)
According to the US EPA, the primary sources of formaldehyde within a home are often pressed wood products manufactured with adhesives containing urea-formaldehyde (UF) resins (8). The typical concentrations of pollutants in older homes that do not have UFFI (Urea-Formaldehyde Foam Insulation) are usually below 0.1 parts per million (ppm), however, if these homes contain a substantial amount of recently installed pressed wood products, the levels can exceed 0.3 ppm.(8).
The Hazards of Formaldehyde Emissions:
Formaldehyde, a colourless and pungent gas, is a known carcinogen (4), and its presence in MDF is primarily attributed to the urea formaldehyde (UF) glue used in its manufacturing process. UF glue, composed of urea and formaldehyde, is essential for binding the wood fibres together to create MDF. However, excess formaldehyde may be added to enhance bonding strength, leading to higher emissions of formaldehyde gas.
These emissions can persist for months or even years after MDF production, posing health risks to individuals exposed to the gas.
The International Agency for Research on Cancer (IARC), a division of the World Health Organisation, has reclassified formaldehyde from a group 2A suspected carcinogen to a confirmed carcinogen (5). It's important to note that the carcinogenic properties of formaldehyde are primarily observed at extremely high concentrations, which are hundreds of times greater than the levels emitted from plywood products. Exposure to formaldehyde generally occurs inhaling airborne gas, but it can also be absorbed through the skin or ingested (5).
Prolonged exposure to formaldehyde can increase the risk of various health problems, including nasal and sinus cancer, leukemia, respiratory irritation, and allergic reactions (6). Furthermore, there is limited evidence suggesting potential adverse effects on fetal development and female fertility (7).
Australian Standards:
In Australia two voluntary standards address formaldehyde in pressed timber products and establish emission limits. These standards are:
- AS/NZS 1859.1:2004: Specifications for Particleboard
- AS/NZS 1859.2:2004: Specifications for Dry-processed Fibreboard.
Australian Standard: AS/NZS1859.2 - Reconstituted woodbased panels – Dry processed fibreboards; stipulated limits for formaldehyde emission potential are:
Emissions Class Formaldehyde Emissions Limit (mg/l)
Super E0: Less than or equal to 0.3
E0: Less than or equal to 0.5
E1: Less than or equal to 1.0
E2: Less than or equal to 2.0
E3: Greater than 2.0
In Australia to be classified as "low-formaldehyde emission" products, finished pressed-wood items must adhere to test criteria levels of less than 1ppm formaldehyde (3).
Presently, this is a voluntary system but majority of Australian-made particleboards and dry-processed fibreboards meet these standards and qualify as "low-formaldehyde emission" products, however, plenty of imported sub-standard products enter the market so be sure to check with your contractor or building team on where your MDF is being sourced from.
American Standards:
In 2007, the California Air Resources Board (CARB) implemented regulations to limit formaldehyde emissions from composite panels.
Phase 1, in effect, sets a limit of 0.21 ppm,
Phase 2 reducing this to 0.11 ppm.
CARB also approves no added formaldehyde (NAF) and ultra-low emitting formaldehyde (ULEF) products. The U.S. Environmental Protection Agency (USEPA) is considering national adoption of CARB regulations.
What to look for:
While standard MDF contains formaldehyde, it can also be specified as No-Added-Formaldehyde (NAF), meaning its formaldehyde emissions are less than 0.04 ppm. However, as wood naturally contains formaldehyde, technically no wood product can be considered completely formaldehyde-free. The natural formaldehyde level in wood is around 0.01 ppm (7). When looking for MDF, it is important to check what binding agents are used. Formaldehyde free options include:
Soy Glue: There has been discussion about developing a soy-based glue for MDF, similar to that used in plywood, but this product has not yet entered the market.
Plant-Based Glue: While one company claims to offer plant-based glue, further clarification is needed regarding its composition. It's advisable to obtain a sample first, especially for those sensitive to chemicals.
Another option is to look at an alternative to MDF, such as Super E0 or E0 plywood, hemp boards, or solid wood. My post on engineered woods goes into more details.
Suppliers Australia:
Australian Panels: CustomWOOD MDF, Formaldehyde emissions meet the E0 standard of <1.0 mg/L when tested in accordance with AS/NZS 4266.16:2004
Bunnings: MDF Formaldehyde emissions meet the E0 standard of <1.0 mg/L when tested in accordance with AS/NZS 4266.16:2004 (9)
FA Mitchell: 100% of MDF supplied from local plantations, and are from guaranteed renewable sources and are certified with zero formaldehyde emission rating.
Laminex: E0 MDF Raw Product Rangerange; wood fibre is sourced only from renewable pine plantations in Australia, and has extremely low formaldehyde levels (E0).
Timberwood Panels: E0 (Low Formaldehyde Emitting) Standard MDF & E0 (Low Formaldehyde Emitting) Moisture Resistant MDF.
Alternatives
Austral Plywoods: 'A' Bond products (Marine, Exterior, Structural) are certified to Super E0, the lowest emission rating obtainable. 'C' Bond products (Interior) have an E0 rating, the second lowest emission rating.
EkoPly: environmentally-friendly 100% Recycled Post Consumer waste sheet, made from recycled waste plastic, that claims to be safe and eco-friendly, free from hazardous substances according to REACH regulations.
EvoWood Hardboard: Hemp Board formaldehyde free, carry an e-zero emission rating and are manufactured in accordance with FSC regulations using natural binders
Xanita Fibreboard: VOC-Free biocomposite fibreboards from upcycled kraft paper waste
Suppliers USA:
Evertree: dry process and hot-press bonding. Isocyanate and formaldehyde-free Green Ultimate composite wood panels produce the same level of emissions as solid wood (0.01 ppm), which is ten times lower than the EU standard (E1).
Georgia Pacific: ULTRASTOCK® MR range, Manufactured with 100% NAF resin. All UltraStock panels are recognized by the California Air Resources Board (CARB) as no added formaldehyde (NAF)
Medite Smartply: CLEAR & ECOLOGIQUE range, No added formaldehyde FSC® certified. CARB 2 compliant
Roseburg: No-Added Formaldehyde (NAF) range
Uniboard: Nu Green MR50. no-added-formaldehyde MDF, 100% recycled and recovered wood pre-consumer fibre
Unilin: FIBRALUX NAF, Structural MDF board. Approved by the by Air Resource Board (ARB) as a no-added formaldehyde based resin (NAF) MDF board, FSC certified on request
Alternatives:
Chesapeake Plywood: SoyStrong hardwood panel, No Added Urea-Formaldehyde. exceed California Air Resource Board and USGBC LEED Criteria
Columbia Forest Products: PUREBOND® Hardwood Plywood. Formaldehyde-free, soy-based PureBond assembly technology. Made in the US and Canada. Can be specified as FSC® certified upon request
Hemp Traders Hempboard: Made in the USA from American grown hemp, can be used in place of wood particleboard or MDF. Non-formaldehyde binders
Panguaneta Plywood: PureGlue™ Plywood is made with no added formaldehyde, through an innovative non-toxic gluing system.
Sunstrand CoreBoard: Proprietary blend of natural, rapidly renewable materials, water-based binder, low VOC.
Wheatboard: eco-friendly alternative to MDF fiber board, made of wheat straw, a by-product of harvesting wheat. It is perfect for cabinetry, casework, wall panels, and furniture in both commercial and residential spaces.
Final Thoughts:
Given the potential health risks associated with formaldehyde emissions from MDF, it is crucial for consumers, builders, and manufacturers to remain vigilant and informed. Proper ventilation, use of personal protective equipment, and selection of low-emission or formaldehyde-free MDF products can help mitigate these risks and promote healthier indoor environments.