Sunscreen manufacturers may be looking into changing the chemicals they use and altering their peelable labels to say so after a study into nanoparticles.

Consumer Reports carried out an investigation in the US to assess the ingredients used in various products, California Watch reports.

It was found that many brands contained nanoparticles such as titanium dioxide and zinc oxide even when they said they did not.

A number of manufacturers are now using these substances to make their formulas clear and avoid leaving a white residue.

Carolyn Cairns from Consumer Reports, said: "Scientists worry these nanoparticles, which are measured in nanometers, might be dangerous to human health."

She pointed out that they could get into the bloodstream and perhaps generate free radicals, as well as end up in the water table.

While experts warned that the public should not avoid sunscreen, it may be best to look out for products that are free from these ingredients.

Earlier this summer, the Food and Drug Administration ordered the removal of terms such as 'waterproof' and 'sweatproof' from the peelable labels of sunscreen products, something that could encourage the UK to follow suit.

Denny Bros Ltd, 15 August 2011