Hazardous substances in wood products

When working with the reuse and recycling of wood, it is essential to be aware of the risk of hazardous substances in the products you are handling. On this page, you can learn more about hazardous substances in wood products, and at the bottom of the page, there is a quiz to test your knowledge in this area.

Disclaimer: This is not a comprehensive guide on how to carry out the renovation or demolition of structures containing hazardous substances but an introduction to some of the key considerations to be aware of.

Teacher's guide:

3. Wood_EN.pdf

 

Where are the hazardous substances?

When working with reused wood from demolition or renovation, it's crucial to be aware that there may be environmentally and health-hazardous substances in the old building materials. You may encounter them when replacing doors and windows, installing new floors, sanding old ones, removing wallpaper or paint, remodeling bathrooms and kitchens, or constructing an extension.

Wood products can be surface-treated with paint, varnish, and glue containing hazardous substances. Alternatively, the wood can be impregnated with hazardous substances throughout.

Wood can also absorb hazardous substances from surrounding materials, such as chemicals from seals around old windows penetrating the wood. There are three types of wood that you can learn more about below:

1. Clean wood

Clean wood may appear in construction as structural timber, especially in older residential buildings, for example, in floor structures or roof constructions.

2. Surface-treated wood

Surface-treated wood is typically found in doors, windows, kitchen cabinets, and wooden floors. It is not guaranteed that surface-treated wood is suitable for recycling. For instance, paint may contain heavy metals and PCBs. In windows used in construction between 1950 and 1977, attention should be paid to the fact that window seals may contain PCBs, which may have contaminated the window frame.

This is also why wood from windows from that period should be mapped for PCB and other relevant environmentally hazardous substances before being removed from the building.

3. Impregnated wood

Previously, chrome, arsenic, and creosote were commonly used for wood impregnation, and there is still a risk of finding wood impregnated with these substances. Today, copper, boron, and various organic substances are used for impregnation.

Other pressure-treated wood may be greenish due to containing copper, but it can also be colorless. Wind and weather can alter the wood's appearance, causing it to turn gray. Additionally, paint is often applied on top of the impregnation, making it challenging to distinguish it from painted wood that is not pressure-treated.

Types of reusable wood and potential problems

  • Wood painted with indoor paint: Can be problematic as the paint may contain harmful substances such as lead and other heavy metals.
  • OSB boards, plywood, particleboards: These materials may contain adhesives and chemicals, making recycling problematic.
  • Pallets, planks, wooden floors, door frames: Can be recycled with appropriate treatment and removal of any contaminating materials such as paint or impregnation. Knowledge of the wood's history is essential, especially if there is a risk that the wood has been in contact with hazardous substances.
  • Wooden furniture without upholstery, solid wood kitchen elements: Can be recycled, but if the wood is impregnated or treated, it can pose a problem for the reuse process.
  • Kitchen elements made of particleboard: These can be problematic due to the adhesives and chemicals used in production.
  • Impregnated wood: Often contains toxic substances such as heavy metals or chemicals, making recycling difficult and potentially hazardous.
  • Wood painted with outdoor paint, furniture/sofas with fabric or foam, MDF boards: These may contain toxic substances or be challenging to recycle due to the content of adhesives, paint, or fabric treatment.

What are hazardous substances in wood products?

There are many different hazardous substances to be aware of when working with wood. These eight different substances presented here are problematic, and it is important that you are familiar with them to avoid exposing yourself or others to them when you work with the reuse and recycling of wood. How many are you already familiar with?

1. PCB

PCB stands for polychlorinated biphenyls and is an organic environmental toxin. There are 209 different types of PCBs (congeners). PCB is especially found in joint sealant, double-glazed windows, LED lights, as well as durable paints and floor coverings in buildings constructed or renovated between 1950 and 1977.

Additionally, PCB has been used in capacitors and transformers until 1986. The use of PCB is prohibited today. The prohibition has been in effect for building materials since 1977 and in all other contexts since 1986. PCB is a persistent organic environmental toxin and is covered by the Stockholm Convention.

Why is PCB dangerous?

PCBs can cause damage to reproductive ability, the immune system, and the liver, while also being hormone-disrupting and suspected of being carcinogenic. In nature, these substances accumulate and break down slowly. There is significant concern about PCBs because humans can be exposed to them when PCBs evaporate from seals into indoor air. If PCBs are not removed from waste, they can spread to the environment and accumulate through the food chain, leading to human exposure through diet.

2. Asbestos

Asbestos consists of minerals that can be split into fibers. Asbestos was widely used in construction until 1990 when a definitive ban on asbestos use was implemented. Asbestos has been used in various building materials, such as asbestos-cement sheets.

Handling asbestos waste can generate dust containing fibers that can accumulate in the lungs. The dust may be so fine that it is not visible to the naked eye. Inhaling asbestos fibers can cause lung and pleural cancer, as well as the disease asbestosis, which is a chronic lung condition.

Why is asbestos dangerous?

Asbestos, when removed, is considered waste and must not be reused or recycled. It must be handled according to hazardous waste regulations unless it is non-dusty

3. Lead and heavy metals

In many residences, there are heavy metals in the paint. Lead, in particular, was used in paint in significant quantities for many years, continuing until the year 2000. Lead-based paints are often used on woodwork and structures where there is a risk of rising ground moisture or where the paint needs to be more resistant.

If you sand or burn surfaces painted with lead-based paints, the heavy metals will be released into the air as dust or gases. This poses a risk of inhalation, leading to health damage for you and others. Lead is now prohibited in construction.

Why are lead and heavy metals dangerous?

Lead affects the nervous system, and children are particularly sensitive. Lead is toxic to water and soil organisms and accumulates in nature and in humans. Lead can spread to the environment if, for example, paint with lead content is not removed from construction waste before crushing. As a result, it can accumulate through the food chain.

4. Arsenic

Arsenic is a chemical element with the symbol As. Arsenic can exist in various forms, such as As(III) and As(V). Arsenic has been used in wood preservatives and paint. The use of arsenic began to be phased out around 1990.

Arsenic can spread into the environment if paint containing arsenic is not removed from construction waste before crushing. As a result, it can accumulate through the food chain. Pressure-treated wood with arsenic is generally considered hazardous waste, unless analyses show that the amount is below the hazardous waste threshold. Pressure-treated wood with arsenic is typically deposited in landfills.

Why is arsenic dangerous?

Arsenic is toxic to humans, causing both acute and chronic effects. It can lead to skin, nerve, liver, and gastrointestinal damage. Additionally, the substance is carcinogenic.

5. Copper

Copper is a metal with the symbol Cu. Copper is used, for example, for plates for roofs and facades, pipes, alloys, and electrical cables. It can also be used for wood impregnation and wood protection. Copper has been used in paint.

Copper can spread to the environment if paint with copper content is not removed from construction waste before crushing. As a result, it can accumulate through the food chain.

Why is copper dangerous?

Copper is not good for the environment. Some copper compounds are toxic to aquatic organisms. Copper can inhibit the growth of plants.

6. Chlorinated paraffins

Chlorinated paraffins are a complex mixture of substances and exist as short-chain (SCCP), medium-chain (MCCP), and long-chain. Chlorinated paraffins have, for example, been used in sealants, and when the use of PCB was banned in the late 1970s, there was an increased use of chlorinated paraffins. In 2002, Europe began phasing out the use of these substances.

The use of chlorinated paraffins dates back to 1950 and probably earlier. The production, marketing, and use of SCCP have generally been prohibited in the EU since 2012. Chlorinated paraffins are a persistent organic pollutant and are covered by the European POP regulation. In 2015, threshold values for SCCPs were established in the POP Regulation, which means that waste containing over 10,000 mg/kg must be treated in a manner that destroys the substance.

Why are chlorinated paraffins dangerous?

Chlorinated paraffins are potentially hormone-disrupting, and SCCP is suspected to be carcinogenic. Additionally, they are toxic to the aquatic environment. Chlorinated paraffins can spread to the environment if not removed from waste. This can lead to accumulation through the food chain, exposing humans to the substance.

7. Formaldehyde

Formaldehyde has the chemical formula HCHO. At room temperature, the substance appears in a gaseous state. In combination with substances such as urea, melamine, and phenol, formaldehyde can be used in adhesives, such as those found in plywood and particleboard. The aqueous solution of formaldehyde is formalin, which is used for disinfection or preserving biological specimens. Formaldehyde can be present in adhesives and varnishes.

Additionally, it may be used in wood-based panels such as plywood and particleboard, commonly used in construction, furniture, and fixtures. The binder in mineral wool products (e.g., insulation and acoustic ceilings) can also release formaldehyde.

Formaldehyde can off-gas into indoor environment from wood-based panels and acid-curing varnish. However, particleboards, plywood, and similar panels produced after 1983 are not expected to emit formaldehyde in problematic concentrations. Formaldehyde is typically not included in environmental assessments. Nevertheless, in the context of reusing and recycling materials, attention should be given to regulations regarding formaldehyde in materials. This is important to ensure awareness of whether the reused or recycled materials may contain or emit formaldehyde.

Why is formaldehyde dangerous?

At elevated concentrations, formaldehyde can irritate the eyes and respiratory system. Prolonged exposure may lead to cancer in the respiratory system.

8. PFAS

PFAS compounds are a collective term for a group of perfluoroalkyl and polyfluoroalkyl compounds. Up to 12,000 PFAS compounds have been identified. These substances are human-made and possess properties that make them, for example, water and grease repellent, and many of them are surfactants. Due to their properties, they are widely used and added to products such as paint and varnish. This broad application means that PFAS compounds are found in many environmental settings.

 

 

There have been no specific studies on where PFAS occurs in buildings. Due to the lack of systematic testing for PFAS in buildings before demolition and renovation, there is not much data in this area. In 2022, Eurofins conducted analyses on 25 paint samples as well as samples of concrete, glazed tiles, linoleum, and wallpaper. They found that 23 out of 25 paint samples exceeded the soil quality criterion for PFAS-4 (while none of the samples exceeded the quality criterion for PFAS-22). PFAS was also found in some of the wallpaper and linoleum samples.

Why are PFAS dangerous?

Although PFAS is a diverse group of substances, the majority of them are difficult to break down and can accumulate in plants, animals, and humans. Additionally, they are mobile in the aquatic environment. This group of substances also has varying effects on human health. Some of the substances are harmful to reproduction, carcinogenic, or suspected to cause cancer and can cause damage to organs as well as harm eyes and skin.

How to identify hazardous substances?

Environmental mapping:

During demolitions and renovations, the developer in most countries is obligated to conduct an environmental mapping. The purpose of conducting an environmental mapping of the building is to locate and map the environmentally hazardous substances and contaminated building components so that the performing craftsmen can plan the working environment and necessary protective equipment.

In practice, environmental mapping involves taking samples of specific types of building materials known to potentially contain hazardous substances. These samples are then sent to an accredited laboratory capable of analyzing the specific substances the building material might contain. The classification as clean, contaminated, or hazardous waste is then determined based on applicable regulations.

The goal of environmental mapping is to sort out and treat of hazardous substances under controlled conditions, preventing them from entering nature through the recycling of materials from demolition or renovation work.

Resource mapping:

Resource mapping refers to a detailed examination of a building to identify available resources before demolition or renovation. This mapping provides a comprehensive overview of materials suitable for reuse, recycling, and material recovery.

The effectiveness of resource mapping depends on conducting it in the project's initial phase, combined with or as an extension of an environmental screening of the building. Information about harmful substances from environmental mapping is a crucial parameter for assessing whether available materials can be considered a resource or need to be handled as contaminated or hazardous waste. Together, these mappings form the basis for subsequent planning and describing the demolition process.

Material passport

A material passport is a kind of ID card or product declaration for building materials. Material passports can be essential to ensure that hazardous substances in recycled materials are identified and handled correctly throughout their life cycle. It can document and provide information about the specific hazardous substances and their potential impact on the environment and health. This information is crucial for ensuring responsible recycling and reuse of wood materials.

What can recycled wood be used for?

A significant amount of wood waste from construction is currently incinerated and used as an energy source for heating residences. It would be better for the environment if we reused and recycled more wood in the future. But what can the wood be used for?

Wood products for reuse

Any clean wood that is undamaged and free from paint with hazardous substances can be used for reuse. For example, old rafters and floor joists can be used as new rafters in a shed or garage. Used floorboards, without added varnish and hazardous substances, can be reused as flooring in a new building. Used doors and windows with paint free from hazardous substances can also be reused. Clean boards, planks, and battens can be reused for furniture, cladding, and interior use.

Wood products for recycling

Boards, beams, skirting boards, plywood sheets, kitchen cabinets, laminate sheets, battens, planks, and chipboard can all be recycled into new products. Most wood materials can be broken down into fibers and used in new chipboard or wood fiber insulation. Some can be used for OSB and plywood sheets, while solid beams and boards can be used with new wood for new glued laminated timber beams or CLT elements.

Wood products for combustion

Wood products like laminate floors, rotten wood, windows and doors with paint, as well as masonite and MDF boards, are not suitable for new products. They are typically burned and used as a heat source.

Wood products for landfill

All wood products screened for hazardous substances and not suitable for incineration are deposited. Pressure-treated wood can only be incinerated at approved incineration plants due to its chemical content.

Duration: Approx. 15 minutes

QUIZ: Where are there hazardous substances?

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