Chemicals in a huge range of household objects such as rubber gloves, condoms and baby dummies can cause cancer , global health chiefs have warned.
Scientists from the World Health Organisation have concluded that MBT, which is used in rubber manufacturing, should be added to its "encyclopaedia of carcinogens".
The long list of products the substance is in also includes, soft playground surfaces made of 'rubber crumb', medical catheters, car tyres, rubber insoles for shoes, air beds, elastic bands, swimming caps and goggles.
At a meeting in Lyon, France, 24 experts from eight countries concluded that the substance 'probably causes cancer', putting it alongside red meat and only one rung below cigarettes, asbestos and other definite causes of cancer .
Professor Hans Kromhout, a member of the committee which reviewed the chemical, said MBT had been identified "in gloves and baby bottle teats and soothers" and more recently in "inhalable road dust with the wearing of rubber tyres the most likely source of this contamination."
Data on the substance has been reviewed by the WHO's International Agency for Research on Cancer which also looked at a study of workers at a Welsh chemical factory.
But because the workers were also exposed to other chemicals, it was hard to be certain MBT was to blame, according to the report.
The research, by professor Tom Sorahan, of Birmingham University, linked MBT to bladder cancer, bowel cancer and a type of blood cancer.
The news comes after a former NHS chief claimed that 3G football pitches may have caused his son's cancer.