Coca-Cola and Pepsi have changed the ingredients in their US soft drinks in order to avoid having to put a cancer warning on their packaging.
To comply with new standards introduced in California, the companies have asked suppliers of caramel colourings to reduce the level of chemical 4-methylimidazole in their product.
This colouring can be found in trace amounts in many foods and is a big ask from the soft drink giants.
The changes are being made to drinks sold across the US but are not set to be introduced in the UK or Europe.
Studies in the lab had found that the ingredient ’4-methylimidazole’ – which gives the drink its caramel brown colour – caused cancer in mice and rats.
This led to the state of California adding the chemical to its official list of ingredients that may cause cancer – or ‘carcinogens’ – earlier this year.
Under the state’s law, Coca-Cola and Pepsi would have had to put cancer warning labels on bottles and cans alerting the public to the possible risk.
Officials point out that consumers would need to drink 1,000 cans of Coke a day to get the same dose of the chemical that was linked to tumours in mice.