Lipsticks popular with teenage girls are laced with potentially harmful chemicals which could cause cancer, a study found.
Chromium, a heavy metal recognised as a carcinogen and linked with stomach cancer, was discovered in a range of 32 "very common" lipsticks costing as little as £3.50 by researchers at the University of California.
Researchers found that 10 of the lipsticks would expose the wearer to more than double the acceptable daily intake of chromium, if used on a daily basis - although the names of the implicated brands are currently being kept hidden from consumers.
A range of other toxic metals were discovered in lipsticks, which could be potentially harmful if the product was used an average amount - two or three times a day.
They included aluminium, cadmium, and manganese, which were discovered in doses exceeding recommended daily intake by 20%, according to average use.
The study also concluded there was no meaningful difference in the levels of the chemicals present in cheaper lipsticks and more expensive brands.
Under EU law, many of the chemicals are banned from high street shelves in Britain, although chromium currently is not.
'A wake-up call'
Critics have suggested the study poses serious questions for the cosmetics industry.
Prof Katharine Hammond, who took part in the research, said: "Just finding these metals isn't the issue; it's the levels that matter."
Anti-chemical campaigner Elizabeth Salter Green said: "The worrying levels of metal in US lipstick should be a wake-up call to all areas of the world, including the EU, and they ought to be removed.
"Some of these toxic metals are occurring at levels that could possibly have an effect on long-term health.
"There needs to be improved testing for not only the individual chemicals themselves, but also what effects the 'whole cocktail' of our exposure to harmful metals and chemicals may be."
However biologist Dr Chris Flower, of the Cosmetic, Toiletry and Perfumery Association, declared lipsticks on sale in Britain safe.
He said: "The traces of metals found in lipsticks are vanishingly small amounts, but they are there because they are everywhere in the environment. They get in food because they are in the soil.
"However, lipsticks are strictly regulated by stringent EU cosmetic safety laws that ensure that such amounts never reach unsafe levels.
"To put in context the amount of lead found in the samples from the study, you would get 1000 times more lead from safe drinking water than you would from using those lipsticks."