Canadian foods are among the most contaminated with flame retardant chemicals in the world, with levels up to 1,000 times those found in European countries, according to the Globe and Mail newspaper.

Research commissioned by The Globe and Mail and CTV News found polybrominated diphenyl ethers (PBDEs) in everyday foods such as salmon, ground beef, cheese and butter, the paper said.

PBDEs are used as flame retardants in foams, textiles and plastics, the paper said. It described them as "ubiquitous in modern homes, with the chemicals leeching out of furniture, rugs and electronic products, such as televisions and computers."

Their impact on human health is not clear and safe levels have not been established it said. "These are persistent toxic chemicals . . . and certainly it is undesirable to have these toxic chemicals in our food supply," said Arnold Schecter, professor of environmental sciences and public health at the University of Texas.

The paper commissioned an independent laboratory to test 13 everyday foods. It found a level of PBDEs of 3,638 parts per trillion in farmed rainbow trout and 1,942 ppt in farmed Atlantic salmon. "Only chicken had virtually undetectable levels," the paper said. "Environmental chemicals tend to accumulate in fat, so not surprisingly fattier foods had higher levels."

"Even though we don't know exactly the meaning of these levels for the health of children or adults . . . we think the smaller the amount, the safer it would be for people eating the food," Dr Schecter said.

But the Canadian health authorities deny that there is any risk. "The levels found in food are very low. They vary in parts per trillion and very low parts per billion — levels that in general were found to not pose a health risk for Canadians," said Samuel Ben Rejeb, associate director of the bureau of chemical safety in the health products and food branch of Health Canada