Petrol: general information
Updated 3 June 2024
© Crown copyright 2024
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/petrol-hydrocarbon-chemical-incident-information/petrol-general-information
Petrol definition
Petrol is a complex mixture of hydrocarbons (typically of chain length C4-12). It is produced by mixing fractions obtained from the distillation of crude oil with brand-specific additives to improve performance. Under normal conditions, it is a volatile liquid with a characteristic odour.
Petrol is highly flammable and may cause fire or explosions if not handled appropriately.
What petrol is used for
In the UK, petrol is mainly used as a road transport fuel, with additional use in other motors (lawnmowers, cement mixers and so on). Petrol has also been used historically as a solvent in paints and for cleaning metal surfaces (degreasing).
Petrol in the environment
Substantial quantities of petrol are generally only found in the environment as a result of accidental release from an industrial site or transport vehicle. There are no natural sources of petrol. Vehicle engines may emit a very small amount of unburnt petrol in exhaust fumes.
Human exposure to petrol
Exposure to petrol may occur if it is used in the workplace. You may be exposed if you use petrol in a vehicle or any other motor, store it, or siphon it.
The effect of petrol on health
The presence of petrol in the environment does not always lead to exposure. In order for it to cause any adverse health effects, you must come into contact with it.
You may be exposed to petrol by breathing its vapours, or drinking it, or skin contact.
Following exposure to any chemical, the adverse health effects you may encounter depend on several factors, including the amount to which you are exposed (the dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals.
Low-level exposure
At low levels of diluted petrol in the water, levels of exposure are unlikely to cause any symptoms.
High-level exposure (to neat petrol)
Drinking neat petrol may lead to nausea, vomiting and abdominal pain. In serious cases damage to the digestive tract, coma, loss of muscle control, and heart and lung problems can occur.
If petrol is swallowed, medical advice should be obtained immediately.
A severe form of lung damage called pneumonitis may occur if liquid petrol is inhaled directly into the lungs, for example, whilst manually siphoning a tank or from inhaling vomit after swallowing petrol. This is why it is important not to make someone sick if they have swallowed petrol.
Breathing in petrol fumes (not vehicle exhaust) may cause dizziness, drowsiness headaches. Breathing in large amounts can result in coma, loss of muscle control, heart and lung problems.
Petrol can cause the skin to become irritated, dry and cracked. If the skin is exposed for a long time then burns may develop. Dermatitis (eczema) can develop if exposure to the skin happens often.
Neat petrol is highly flammable – it and its fumes may cause fire or explosions if not handled appropriately.
Smell
The odour threshold for petroleum products is very low. That means that people can smell it in the air at very low concentrations.
Outdoors, odours quickly disperse in the air whilst inside properties and confined spaces, odours appear stronger unless there is sufficient ventilation.
Typically, even when people can smell petrol, it is usually at low levels and unlikely to be explosive or cause any health risk.
Petrol in drinking water
Much like when we can smell petrol in the air, the detectable threshold of petroleum products dissolved in water is very low. That means people can smell and taste hydrocarbons in their drinking water at very low concentrations and so are unlikely to drink it.
Drinking water standards for hydrocarbons
The World Health Organization (WHO) produces international norms on water quality and human health in the form of guidelines that are used as the basis for regulation and standard setting world-wide. These are based on lifetime exposure and considering vulnerable groups.
There are also UK Drinking Water Regulatory Limits set out by the Drinking Water Inspectorate (DWI) to ensure drinking water is wholesome and protective of public health by law.
Petrol and cancer
The International Agency for Research on Cancer (IARC) found that there was some evidence that petrol could cause cancer in experimental animals, but the evidence in humans was inadequate. If any, the risk of cancer from short-term exposure to petrol is likely to be low.
Petrol exposure during pregnancy
Exposure to amounts of petrol that do not harm the mother are not likely to harm the unborn child.
The effect of petrol on children
Children exposed to petrol would be expected to display similar effects to those seen in exposed adults. Petrol stored around the home should be kept out of the reach of children and in an appropriate container.
Swimming pool use in areas of contaminated water
UKHSA strongly recommends that children and infants do not use swimming pools in areas affected by petrol contamination where a no-drink notice has been issued, as it is difficult to avoid children and babies consuming the pool water.
UKHSA also recommends that adults do not use their swimming pools in the affected area. However, if they choose to do so they should minimise the amount of water they drink while in the pool.
What to do if you are exposed to neat petrol
You should remove yourself from the source of exposure.
If you have ingested neat petrol seek medical advice – do not make your yourself sick.
If you have inhaled neat petrol you should seek medical advice.
If you have got neat petrol on your skin, remove soiled clothing (not over the head), wash the affected area with lukewarm water and soap for at least 10 to 15 minutes and seek medical advice.
If you have got neat petrol in your eyes, remove contact lenses, irrigate the affected eye with lukewarm water for at least 10 to 15 minutes and seek medical advice.
Additional sources of information
HSE: If you store petrol at home, at a club, association or similar premises
HSE: Dispensing petrol as a fuel: Health and safety guidance for employees