Since the illness was first detected in 1996, wild devil sightings have fallen by more than 50 percent.
The small carnivore is now considered "vulnerable" under Australia's Environment Protection and Biodiversity Conservation Act.
Experts have been racing to find the cause of—and hopefully a cure for—the illness before the devil goes extinct in the wild.
In February 2006 researchers announced that the disease most likely spreads when the animals bite each other during mating battles.
But no one is sure what triggered the cancer in the first place.
Hamish McCallum, professor of wildlife research at the University of Tasmania, said it's unlikely the chemicals caused the devils' disease.
"It's a really, really strange tumor. All the tumor cells in all the devils are essentially a clone—they are all derived from one individual," McCallum said.
"The event that caused that original mutation to malignancy will never be known," he continued.
"It happened a minimum of ten years ago, and in terms of managing the disease, it's essentially irrelevant."
However, "it's not beyond the bounds of possibility that [biphenyls] may suppress the devils' immune systems in such a way that it makes them more likely to develop the cancer," he said.
McCallum thinks the devils in the new study could have easily ingested biphenyls directly.
"You've got to remember that devils are scavengers," he said.
"Throughout Tasmania people maintain outdoor dumps. If somebody chucked a wallaby carcass on top of say, a foam mattress, then the devils might actually consume quite large quantities of that foam."
In response to the new study, wildlife managers have called for funding for further, more comprehensive tests on the devils.
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