E-numbers / Other additives / E940
also: CFC-12 · Freon-12 · R-12
A chlorofluorocarbon (CFC-12, Freon-12) once used as a food freezant and propellant. No longer an approved food additive in the UK or EU.
Scan a barcode to check a food for dichlorodifluoromethane. NutraSafe Pro · £6.99/month · iOS
E940 is not a permitted food additive in the UK.
Why it’s worth knowing. E940 is not a permitted food additive in the UK. Its manufacture was banned globally under the Montreal Protocol because CFCs destroy the ozone layer. It should not appear on any UK food label.
Dichlorodifluoromethane is a chlorofluorocarbon gas, also known as CFC-12 or by the trade name Freon-12. It is a colourless, odourless, non-flammable gas at room temperature. It belongs to the family of halogenated hydrocarbons that were widely used as refrigerants, aerosol propellants, and industrial solvents throughout the mid-twentieth century.
In historic food applications, the compressed liquefied gas was used as a direct-contact freezant (sprayed onto food to freeze it rapidly) and as a propellant in aerosol food cans. On contact with food, the rapidly expanding liquid absorbs heat and freezes the surface. The gas itself does not interact chemically with food components.
Historically found in a narrow range of canned and frozen products where rapid chilling or an aerosol propellant was needed, including some canned cream and frozen food lines. Use was already minimal by the 1980s. It has not been authorised for food use in the UK or EU in the modern regulatory era. On a label it would appear as 'dichlorodifluoromethane' or 'E940', but neither should appear on any product sold in Great Britain today.
CFC-12 has an ozone depletion potential of 1.0, the benchmark against which all other CFCs are measured. When released into the upper atmosphere, it breaks down and releases chlorine atoms that catalyse ozone destruction. This environmental hazard, not direct human toxicity at food-use levels, drove its global phase-out. Developed countries phased out production by 1996 under the Montreal Protocol; developing countries followed by 2010.
CFC-12 has the highest ozone destruction potential of all common refrigerant gases and was phase out globally under the Montreal Protocol on Substances that Deplete the Ozone Layer.
At the trace levels historically associated with food use, no adverse human health effects were established. At high atmospheric concentrations (occupational or industrial exposure) the substance can sensitise the heart to arrhythmias, reduce respiratory capacity, and cause central nervous system depression. These effects are not relevant to the residual contact a consumer would have had with food frozen using the gas, as virtually all gas dissipates before consumption.
At high inhalation concentrations, CFC-12 sensitises the myocardium to adrenaline-induced arrhythmias and produces CNS depression. Effects are concentration-dependent and not observed at trace environmental levels.
Rat and dog feeding studies with CFC-12 used as a food freezant found an acceptable daily intake of up to 1.5mg/kg body weight with no observed adverse effect at that level.
E940 should not appear on any UK food label today. If you see it listed as an ingredient, the product may be improperly labelled or imported from a jurisdiction with different rules. There is no dietary or allergy-specific group that needs to individually avoid it, because it is not in the food supply.
E940 is unusual among E-numbers in that the reason it disappeared from food is almost entirely environmental rather than a human health finding. The Montreal Protocol banned its production because CFCs punch a hole in the ozone layer, not because of any established harm to the person eating food frozen with it. Historical animal feeding studies found a low-hazard profile at food-contact levels. That context is real but it does not change the bottom line: the substance is not authorised for food use in the UK, it is not in any current product, and no consumer decision is needed beyond noting its absence from shelves.
E940 is not listed as an approved food additive in the UK. The FSA approved-additives register does not include it. Production of the underlying substance (CFC-12) was banned globally under the Montreal Protocol from 1996 in developed countries, which made its continued food use unviable.
The reason was environmental, not a food-safety finding. Dichlorodifluoromethane is a chlorofluorocarbon with the highest ozone depletion potential of any common refrigerant. Its manufacture was banned under the Montreal Protocol to protect the ozone layer. Once production stopped, food-industry use ended with it.
No UK food products sold today should contain E940. Historically it appeared in some canned and frozen food lines as a freezant or propellant, but use was already rare by the 1980s and ceased entirely after the Montreal Protocol phase-out.
Dichlorodifluoromethane is a synthetic gas with no animal-derived components. It would be considered vegan. However, the question is academic because it is not present in UK food products.
Last reviewed: 20 June 2026
It's the only app that does thisUKJaneK
You Need This AppGmac2005
Best AppGK getting skinny UK App Store reviews
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
NutraSafe Pro · £6.99/month · iOS
