Many people are concerned about the health risks involved in the use of Medium Density Fibreboard.
I was one of the first users of MDF in the UK before it became generally available and recognized for its versatility, stability and, finish. And I know what an unpleasant dust it is to work with. Not only is it an irritant to throat and nose, but the dust is incredibly powder-like and invasive. However once the work has been finished, either with paint it seems that MDF dust ceases to pose a risk.
WHAT IS MDF?
Wood based boards are used almost everywhere, there are three main types;
Laminated Board. Differing wood grain is used for each layer and is then
glued together giving the wood increased rigidity. Types of laminated wood
include plywood and blockboard.
Particle Boards: For example wood chipboard or flexboard. Here raw
material is processed to produce particles of varying size and is then
bonded with a resin binder.
Fibre Boards: Types of fibreboard are differentiated by the size and type
of wood fibres used, the method of drying, what type of bonding agent is
used and the method by which it is pressed into shape.
Medium Density Fibreboard is manufactured by a dry process at a lower
temperature than for example hardboard, another type of fibreboard. The
effect of this is that the natural glues and resins contained within the
wood are rendered ineffective. MDF therefore uses manufactured bonding
agents and resins. Varying density boards with differing finishes are used
for various end uses.
WHY BE CONCERNED ABOUT MDF?
In all fibreboards, formaldehyde resins are used to bond together the
constituent parts. This is usually urea formaldehyde, but some fibreboard
including exterior or marine quality board will use stronger glues such as
Even at a low level, exposure to formaldehyde though inhalation can cause
irritation to the eyes, nose, throat and mucous membrane. Formaldehyde can
also affect the skin, leading to dermatitis, and the respiratory system
causing asthma and rhinitis. The International Agency for Research on
Cancer (IARC), part of the World Health Organisation, quoted evidence that
even short term exposure to formaldehyde, at far below the legal limit
allowable in Britain, could cause irritation to the eyes, nose and throat.
The IARC's findings also stated that wood dust is a carcinogen' (cancer
causing) and that 'formaldehyde is probably carcinogenic to humans'. IARC
was also concerned about the reproductive hazards of formaldehyde'.
Formaldehyde is classified in the UK and throughout Europe as a Category 3
Carcinogen. This means it is a substance which "causes concern for humans
owing to possible carcinogenic effects but, in respect of which, available
information is not adequate for making a satisfactory assessment." This
puts formaldehyde on the GPMU list of potential carcinogens, meaning it
should be replaced where possible, and if not, subject to rigorous controls
that reduce exposure to the lowest possible level.
HAVE OTHER COUNTRIES BANNED THE USE OF MDF?
Rumours that MDF is banned in America and/or Australia are unfounded.
However the US limits formaldehyde emissions from MDF to 0.3ppm (parts per
million), and home owners in California were warned that their new home had
been built using MDF: which "contains a chemical known to cause cancer,
birth defects or other reproductive hazards". Australia has a tighter
exposure standard than Britain and warns its workers that formaldehyde is
'a probable carcinogen' and a sensitiser (i.e. it can cause allergic
reaction such as asthma).
In Germany the exposure limit is 0.lppm, and Norway and Hungary both have
lower exposure limits than Britain and list formaldehyde as an allergen and
In the UK, the Health and Safety Commission's Advisory Committee on Toxic
Substances is now being asked to review the hazards of working with MDF.
WHAT CAN BE DONE TO REDUCE THE RISKS FROM MDF?
Formaldehyde is recognised by the Health and Safety Executive as a
hazardous substance and as such has been given a Maximum Exposure Limit
(MEL). The MEL for formaldehyde is 2ppm and at no time should this limit
be exceeded. The Control of Substances Hazardous to Health Regulations
(COSHH) 1994 states that an employer must try to get as far below a MEL as
is reasonably practicable.
The employer has a general duty to ensure the health, safety and welfare of
their employees. Under the Management of Health and Safety at Work
Regulations 1992 (Regulation 3), an employer is legally obliged to carry
out a risk assessment. This risk assessment should lead the employer to
introduce measures to eliminate or adequately reduce risks.
COSHH Regulation 6 further states that, no employer may carry on any work
liable to expose employees to substances hazardous to health, unless a
suitable and sufficient assessment of the risks created by that work, and
of the steps needed to comply with COSHH in respect of it, has been made.
If formaldehyde in MDF is being used, and cut or worked, at your workplace
your employer should first try to use a safer material. If there is no
alternative to using fibreboard then your employer should consider low
emission board. Some board manufacturers are advertising low formaldehyde
or zero formaldehyde emission boards made to the stringent German 'E1'
standard. This standard is currently being reviewed by the European Union.
Where dust cannot be eliminated, the employer has to introduce control
measures which will adequately reduce dust levels. This will require
adequate ventilation. The most effective control measure is Local Exhaust
Ventilation. The exhaust mechanism is normally attached to the workstation
where board is being cut. As wood fibres are released from the board the
exhaust should remove them from workplace air. This ensures that most of
the dust is removed from the atmosphere as board is worked. Your employer
should also keep the workplace clean and ensure that the workplace is free
of any dust. Gloves should be provided to avoid formaldehyde coming into
contact with the skin, and suitable masks should be provided to avoid
inhalation or ingestion of fibres.
The Health and Safety Executive (HSE) has announced the publication of a Hazard Assessment Document for medium density fibreboard (MDF). The publication of this document follows on from an announcement in October 1997 that HSE would be reviewing the health effects of exposures arising from machining MDF. As part of the review HSE carried out a hazard assessment and commissioned an exposure survey and research into the characteristics of MDF dust/exposures. MDF is a wood composite material, primarily softwood, bonded with a synthetic resin, which is usually formaldehyde-based. It is used industrially in furniture and cabinet making. The atmosphere typically created by machining MDF contains a mixture of softwood dust (and hardwood dust if hardwood is present in the MDF), free formaldehyde, dust particles onto which formaldehyde is adsorbed and, potentially, the resin binder itself and its derivatives. The Hazard Assessment Document for MDF reports on the scientific evidence for the possible health effects of exposures arising from machining MDF and includes information from the HSE commissioned research on the atmosphere created during the machining of MDF. This is the first of a series of Hazard Assessment Documents that will be published by HSE. The health effects of constituents of MDF are: · Formaldehyde can cause irritation of the eyes, nose and throat. In experimental studies in rats, formaldehyde causes nasal cancer. However, there is no evidence that it has caused cancer, either nasal or other, in humans. · Some softwood and hardwood dusts can cause asthma.0Ã¬machining other forms of wood. There is some evidence for more frequent reporting of respiratory symptoms such as nasal obstruction in workers receiving exposures arising from machining MDF compared to other forms of wood or wood products. WATCH expressed the view that the most appropriate risk management strategy for MDF is the one currently recommended by HSE. This specifies that: · The level of dust arising from the machining of MDF should be kept to as low as reasonably practicable below the Maximum Exposure Limits (MELs) for softwood dust and hardwood dust. · Levels of free formaldehyde should be kept as low as reasonably practicable below the MELs for formaldehyde. Softwood and hardwood dusts each have an 8-hour time weighted average MEL of 5mg m-3 (total inhalable dust), whilst formaldehyde has MELs of 2 ppm, as an 8-hour time weighted average and as a 15-minute short term exposure limit. HSE is also preparing free guidance for publication next year aimed at those who use MDF at work. It will summarise the conclusions of the Hazard Assessment Document and the recently commissioned research and will provide a guide to working safely with MDF. Further Information Copies of the new publication, 'Medium Density Fibreboard - Hazard Assessment Document, EH75/1, ISBN 0 7176 1735 1, priced £7.50 are available from HSE Books, PO Box 1999, Sudbury, Suffolk CO10 2WA (tel 01787-881165 or fax 01787-313995).
NOTES TO EDITORS:
1. MDF is a wood composite material, primarily softwood, bonded with a synthetic resin, which is usually formaldehyde-based. It is used industrially in furniture and cabinet making. The atmosphere typically created by machining MDF contains a mixture of softwood dust (and hardwood dust if hardwood is present in the MDF), free formaldehyde, dust particles onto which formaldehyde is adsorbed and, potentially, the resin binder itself and its derivatives.
2. HSE's Health and Safety Laboratory has conducted research:
· into the amount, particle size distribution and morphology of dust created during the machining of MDF compared with that created by machining pure wood
· to investigate the potential for release of free formaldehyde from the resin binders used in MDF
· into the formaldehyde and isocyanate content of MDF dust.
3. The health effects of constituents of MDF are:
· Formaldehyde can cause irritation of the eyes, nose and throat. In experimental studies in rats, formaldehyde causes nasal cancer. However, there is no evidence that it has caused cancer, either nasal or other, in humans.
· Some softwood and hardwood dusts can cause asthma. However, the critical health effect for hardwood dust is sino-nasal cancer. There is some evidence which suggests that softwood dust may cause sino-nasal cancer in humans, of a different histological type to that caused by hardwood dust, but the evidence is inconclusive.
4. Under the Control of Substances Hazardous to Health 1999 Regulations (COSHH), control of exposure to dust can usually be achieved with properly designed dust extraction equipment fitted to the woodworking machine. It is essential that such equipment is kept in good working order and maintained regularly. When using portable or hand-held tools extraction equipment often is not practicable or available, in which case a suitable dust mask should be worn, and if possible the MDF should be machined in a well ventilated place, or outside.
5. In the UK, OELs are set under the COSHH Regulations. Two types of exposure limits are used: the maximum exposure limit (MEL) and the occupational exposure standard (OES). A description of the criteria used to determine which type of limit is applicable is given in the HSE publications EH40, Occupational Exposure Limits and EH64, Summary Criteria for Occupational Exposure Limits.
6. A complete list of OELs is revised and published annually by HSE in its publication EH40, Occupational Exposure Limits. Copies of the 1999 edition (ISBN 0-7176-1660-6) are available, price £8.50 each from HSE Books.
7. While these HSE publications have been assessed and endorsed by WATCH, they are not toxicological data sheets.
8. WATCH is an independent committee consisting of toxicologists, occupational hygienists and other scientific experts. WATCH makes a thorough critical assessment of the available information, prepared by HSE experts, on the human health hazards for specific substances, occupational exposure to these substances and the risks associated with their use in workplaces.
Call HSE's InfoLine, tel: 0541-545500
or write to: HSE Information Centre, Broad Lane, Sheffield S3 7HQ.