Domestic production of biodiesel - health and safety warning

Biodiesel is a relatively new synthetic fuel and is made by treating vegetable oils with chemicals. It is produced commercially and can be bought from some petrol stations.

There are 'recipes' available on the Internet for domestic production of biodiesel. These usually involve mixing vegetable oil with methanol and sodium hydroxide (also known as caustic soda or lye) but other hazardous materials are sometimes used.

Home production of biodiesel raises health and safety concerns because it involves hazardous chemicals and the risk of fire and explosion. It should only be carried out in controlled conditions by people with the proper training and experience.

The main hazards are described below.

Hazardous chemicals

Sodium hydroxide is extremely corrosive. It can cause burning to unprotected skin and is particularly damaging to the eyes. Stirring the liquid can often produce a fine mist of liquid droplets. If this mist is inhaled, severe irritation of the respiratory tract and breathlessness can occur. Accidental swallowing can cause major damage to the throat lining and digestive system.

Methanol is a toxic chemical. It can enter the body through breathing in the vapour, direct skin contact or by accidental swallowing. It can cause nausea, dizziness and visual disturbances that can result in blindness. Swallowing small quantities could pose a significant health threat to the central nervous system and could also affect other vital organs. It is a cumulative poison and repeated exposure to relatively low concentrations could cause harm in the longer term.

Risk of fire and explosion

There is a serious risk of fire and explosion because methanol is highly flammable and there are many potential sources of ignition in most homes, including:

• normal electrical equipment, such as kitchen appliances, plugs and switches;
• open flames, such as gas burners; and
• smoking materials.

It is also possible that a violent chemical reaction could be produced by:

• making a mistake with the recipe, for example getting the quantities wrong or adding the chemicals in the wrong order;
• poor mixing; or
• making too much at once.

Any of these could result in the mixture splashing or boiling over, causing serious burns.

Further information

Safe working with flammable substances Leaflet INDG227 HSE Books 1996 (single copy free or priced packs of 15 ISBN 978 0 7176 1154 6) www.hse.gov.uk/pubns/indg227.pdf

Fire and explosion: How safe is your workplace? A short guide to the Dangerous Substances and Explosive Atmospheres Regulations Leaflet INDG370 HSE Books 2002 (single copy free or priced packs of 5 ISBN 978 0 7176 2589 5) www.hse.gov.uk/pubns/indg370.pdf

Safe use and handling of flammable liquids HSG140 HSE Books 1996 ISBN 978 0 7176 0967 3 http://www.hsebooks.com/Books/search/stepsrch.asp

Designing and operating safe chemical reaction processes HSG143 HSE Books 2000 ISBN 978 0 7176 1051 8 http://www.hsebooks.com/Books/search/stepsrch.asp

HSE publications are obtainable from HSE Books, telephone 01787 881165.

Further information on general health and safety issues is available from HSE Infoline (0845 345 0055).