Dr Linda Gulliver, a senior lecturer at the University of Otago's faculty of medicine, was the only New Zealander on the ''Halifax Project'' task force that made the findings, which were published in an American scientific journal yesterday.
Dr Gulliver was working on a PhD at the university studying the role of estrogen in the development of ovarian cancer when she received an email call-out to join the project.
The research looked at the ''hallmarks'' of cancer - changes that cause cells to become cancerous - rather than studying targets in the body the chemicals were acting on, which has been the standard way of studying carcinogens, and the way Dr Gulliver herself had been studying estrogen receptors, she said.
The 85 chemicals studied by the task force could be found in everything from cosmetics to medical products to toys, and were not classified as carcinogenic by the United States Environmental Protection Agency, Dr Gulliver said.
''You name it, they're ubiquitous.''
Right now, she said, government policy around carcinogens focused on the effect of exposure to individual chemicals, rather than combinations of chemicals.
The threshold for judging whether a chemical was carcinogenic might also be too high, she said.
''[The dose used to judged toxicity] was often a hell of a lot higher than where the chemicals we were looking at were having their effects,'' she said.
''It harkens back to the old saying, `the dose makes the poison'.''
The lower dosages also corresponded to levels at which the chemicals could be found in the environment.
Fifty of the 85 chemicals studied had some effect at low dosages when combined with other chemicals, she said.
There was also the problem of certain chemicals showing ''non-linear dose responses'', which meant they could have ''adverse effects'' at lower doses, but not at the higher doses that were usually taken into consideration when labelling chemicals as carcinogenic.
''At low dosages, they can have quite adverse effects, at higher dosages, they might not have any.''
About 15 of the chemicals were found to display non-linear dose responses.
Dr Gulliver was loath to criticise New Zealand's regulation of chemicals, and said it had ''very stringent'' regulation.
But the research had revealed that, all over the world, government regulations around chemicals may need to be adjusted to account for the combined effect of otherwise non-carcinogenic chemicals, and non-linear dose-response chemicals.
''Our present risk assessments focus on individual chemicals and only at higher dosages. That probably should be looked at.''
Dr Gulliver also thought more research was needed.
Further research would reveal more information around ''which mixture of chemicals could be problematic, what do we find them in, how can we test them now, as chemical mixtures rather than individual chemicals, and what will that do to drive regulations''.
