By Mark Prigg Science Correspondent And Rebecca Lawrence, Evening Standard

 Marks & Spencer is one the stores to be hit by the problem

 An Evening Standard investigation found dozens of products on supermarket shelves containing the chemical, from brand names including Colgate, Aquafresh, Dentyl and Sensodyne.

Anti-bacterial cleaning products, including dishwashing liquid and handwash, are also affected.

Researchers have discovered that triclosan, a chemical in the products, can react with water to produce chloroform gas. If inhaled in large enough quantities, chloroform can cause depression, liver problems and, in some cases, cancer.

Marks& Spencer confirmed today it was removing products containing triclosan from all its stores and has been working with Greenpeace to develop alternative products.

Asda said it was investigating the problem and would be urgently talking to its suppliers.

Giles Watson, a toxicology expert at wildlife charity WWF, warned that the long-term effects of exposure to chloroform were still unknown and advised consumers to check the bottles before buying products.

"These products produce low levels of chloroform, but that adds up over time. The amount of gas formed is very low but I think the key thing is that we just don't know what the effects are. However, manufacturers do have to list triclosan on their ingredients, so if consumers are worried the best advice is to avoid products with the chemical."

A Tesco spokesman said: "We do not use triclosan in any of our own-brand products, apart from one anti-bacterial handwash, which is being reformulated, and our toothpaste. We

believe that triclosan is a very effective ingredient in toothpaste as it helps fight gum disease and improve overall oral care."

The Department of Trade and Industry said use of triclosan was tightly controlled under EU laws brought in last year, but that they were under constant review.

Researchers in the US found that the chlorine added to water in Britain reacted with triclosan to produce chloroform-gas. They found that it was possible for the chloroform produced when soap containing the chemical mixes with chlorinated water to be absorbed through the skin or inhaled.

Professor Peter Vikesland, of Virginia Tech University, who carried out the research, said: "This is the first work that we know of that suggests that consumer products, such as antimicrobial soap, can produce significant quantities of chloroform." He has called for governments around the world to regulate the chemical more closely.

Products affected

Triclosan is in:

Dentyl mouthwash
Colgate Total fresh stripe
Colgate Total
Sensodyne Total Care
Tesco own brand toothpaste
Mentadent P; Aquafresh

Source