Hunter Greens claim coal dust piles along the Southern Maitland railway line are a serious environmental threat.
The Greens say the piles are building up in the Beelbird and Kurri Kurri area are a direct result of uncovered coal hoppers.
Greens candidate for the Hunter, David Atwell, said the piles could become a highly toxic substance called Black Water.
"Black Water is highly toxic and full of all the particles in coal including arsenic and sulphur which are in turn being exposed to the environment which again is another danger to local residents," Mr Atwell told 2NUR.FM
Mr Atwell said covers needed to be implemented to stop the spread of coal dust immediately.
"We also call upon Governments and the coal company and the rail way lines themselves to do a proper clean up," he said.
Mr Atwell also said the coal dust piles were close to a child care centre and an elderly care village, "some of the worst locations where the mounds are located are within two to three-hundred metres of this old aged care village."
