E-numbers / Other additives / E943a
also: n-butane
A colourless hydrocarbon gas used as a propellant to push food products out of aerosol cans. It leaves no residue in the food itself.
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Butane is a simple four-carbon hydrocarbon gas (C4H10) that occurs naturally in crude oil and natural gas.
UK supermarket foods that declare E943a: 7 of the 43,325 we checked (under 0.1%)
Counted by its code or its name in the ingredient list.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
Butane is a simple four-carbon hydrocarbon gas (C4H10) that occurs naturally in crude oil and natural gas. The food-grade form is a highly purified version of the same gas found in lighters and camping stoves. It belongs to the liquefied petroleum gas family alongside propane (E944) and isobutane (E943b).
Butane works as a propellant: compressed into a liquid inside an aerosol can, it vaporises under pressure and forces the food product out through the nozzle. Because it acts purely as a delivery mechanism and is lighter than air, it disperses into the surrounding atmosphere on release rather than depositing into the food. The gas itself does not alter the taste, colour or nutritional content of the food it propels.
Most commonly found in aerosol cooking oil sprays (such as low-calorie vegetable oil sprays used for pans and baking trays), aerosol cream dispensers, and professional food-colour spray preparations. On a UK ingredient label it appears as 'butane', 'E943a', or listed within a 'propellants' bracket alongside propane or isobutane.
The European Food Safety Authority's Panel on Food Additives and Flavourings completed a re-evaluation of butane, isobutane and propane as food additives in January 2025. Because the gas does not meaningfully transfer into the food it propels, dietary exposure from permitted uses is considered negligible. No numerical acceptable daily intake was considered necessary on this basis.
EFSA's FAF Panel re-evaluated butane (E943a), isobutane (E943b) and propane (E944) as food additives and concluded that the available data did not raise safety concerns at the levels used as propellants in permitted food applications.
Toxicological concerns about butane relate to inhalation at high concentrations, not food contact. At food-use levels, the quantity of gas that might dissolve into food is extremely small. The primary human exposure route in aerosol food products is brief inhalation during spraying, not ingestion. Occupational standards for butane inhalation exist but are not relevant to typical consumer spray use.
Butane as a propellant in food aerosols results in negligible oral exposure; inhalation is the relevant exposure route during spraying, though concentrations from brief domestic use are far below occupational threshold values.
No specific population group is advised to avoid E943a in food. People with severe asthma who are sensitive to aerosol sprays in general may wish to avoid aerosol cooking sprays, though the concern there is the spray mechanism rather than butane specifically. Look for 'propellant: butane', 'E943a', or 'propellants (butane, propane)' on aerosol product labels.
Butane's reputation comes from its use in lighters and camping gas, which makes it sound alarming on a food label. In practice, it functions as a mechanical propellant rather than an ingredient: almost none of it ends up in the food. The 2025 EFSA re-evaluation, which reviewed the full body of toxicology data, did not identify safety concerns at food-use levels. The science here reflects a well-understood gas with a long history of regulated food use, not an area of active scientific dispute.
No. Butane (E943a) is an approved food additive in the UK under the assimilated EU Regulation 1333/2008, permitted as a propellant in aerosol cooking sprays and colour preparations.
Only in trace amounts. Butane acts as a propellant gas and disperses into the air on release. The residual amount that could dissolve into food is negligible, which is why no numerical dietary limit has been set for it.
Aerosol cooking oil sprays (low-calorie pan sprays), aerosol whipped cream dispensers, and professional food-colour spray cans are the main products. Check the propellants bracket in the ingredients list.
Yes. Butane is a petroleum-derived hydrocarbon gas with no animal-derived components. It is suitable for vegans and vegetarians.
Last reviewed: 20 June 2026
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