All sorts of chemicals have been linked in one way or another to an increased risk of cancer. You've likely heard of the potential dangers of BPA and phthalates, DDT and triclosan.

But a new years-long review from a team of researchers from around the world shows that there are dozens of potentially dangerous substances that may be of concern. Each chemical may not be dangerous on its own, but when they interact, the combined chemicals can become worrisome.

A global task force of 174 scientists from 28 countries looked at 85 chemicals that aren't considered cancer-causing in humans. They reviewed the effects of those chemicals against the mechanisms that are important for cancer development and found that 50 of those chemicals could be combined to trigger changes that could lead to cancer.

"We found definite evidence that chemicals that are unavoidable in the environment can produce a wide range of low-dose effects that are directly related to carcinogenesis. So the way we’ve been testing chemical safety is really quite out-of-date,” said William Goodson III, a senior scientist at the California Pacific Medical Center in San Francisco in a news release. “Every day we are exposed to an environmental ‘chemical soup,’ and we need testing to evaluate the effects of our ongoing exposure to the mixtures in this soup."

The findings were published in the journal Carcinogenesis. The task force was one of two organized by the Canadian nonprofit Getting to Know Cancer, which is searching for answers about the causes of cancer beyond lifestyle and genetics.

“The results are not conclusive but suggest that additional basic science research is extremely important to fully understand how common chemicals, to which we are exposed at very low doses, can have a cumulative effect on cellular and molecular processes that may ultimately increase risk of some types of cancer,” study co-author Rita Nahta, Ph.D., an assistant professor of pharmacology at the Emory University School of Medicine told Yahoo Health.

Among the chemicals noted were the medications acetaminophen and phenobarbital, butyltins (found in some disinfectants) and titanium dioxide (found in some sunscreens).

"We urgently need to focus more resources to research the effect of low-dose exposure to mixtures of chemicals in the food we eat, air we breathe and water we drink," cancer biologist Dr. Hermad Yasaei, of Brunel University in London, told the Daily Mail.

But Yasaei said he didn't want people to be alarmed by the initial research; these 50 chemicals are safe in low doses. However, the research was carried out to highlight "a gap in our knowledge and we hope this will merit further investigation."

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Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.