Working near busy roads triggers breast cancer, scientists warn after they found at least six women at the same bridge got it within three years of one another.

The group of women all developed a cancer believed to have been caused by exhaust fumes in what researchers have branded a 'new occupational disease'.

There is a one in 10,000 chance the cases were a coincidence, the study said, because the cancers were all so similar and close together.

And another group of seven women developed the disease after working at a tunnel just four miles away at the border between the US and Canada.

Despite scientists going as far as to label a new disease after one woman's ordeal, she was denied any compensation by the Canadian government. 

Research focused on the case of one unnamed woman who worked for 20 years at the Ambassador Bridge between Detroit, Michigan and Windsor, Ontario.

The bridge connects the US with Canada and is the busiest commercial border crossing in North America, seeing 12,000 trucks and 15,000 cars every day.

Assuming the volume of traffic was the same over the woman's 20-year employment and she worked 40 hour weeks, she could have been exposed to the fumes of up to 46.8million vehicles.

Doctors Michael Gilbertson and Jim Brophy, from the University of Stirling in Scotland, believe chemicals in the traffic fumes caused the cancer.

They say the BRCA1 and BRCA2 genes, which try to stop tumours growing, can be shut down by vehicle exhaust fumes.

'These outbreaks of breast cancer represent a new occupational disease,' said Dr Gilbertson.

These women's cases revealed working in the toll booths gave them a 16 times higher chance of breast cancer than the average woman.

The woman in the case study developed breast cancer when she was 44, and then again at the age of 51.

Her diagnosis came within 30 months of five other women working at the same border crossing.

And at the Detroit-Windsor tunnel, four miles away, another seven women were developing the same disease alongside them.

The research was published in the journal New Solutions. 

Source: dailymail.co.uk