A Pilbara council has raised health concerns about Rio Tinto's plan to build a rail line near the asbestos-contaminated former town of Wittenoom.
Rio has submitted environmental documents for a 167km line that would avoid the former townsite, abandoned by all but three residents, but go through the wider Wittenoom asbestos management area.
Wittenoom is declared unfit for habitation because of its deadly blue asbestos, mined in Wittenoom Gorge until the late 1960s.
The Shire of Ashburton is concerned workers could be at risk and wants indemnity from litigation if the railway goes ahead.
The line would link Rio's Koodaideri project to its existing rail line. However, the study phase for Koodaideri is still under way and there is no final decision on how to develop the mine.
Koodaideri could become one of the biggest Pilbara's iron ore mines, exporting up to 70 million tonnes a year.
But some analysts believe its estimated $US3.2 billion cost means it might be delayed.
An Environmental Protection Authority spokesman said Rio's Koodaideri project was being assessed at the highest level before a report went to the Environment Minister.