A new report says prime Ontario farmland is being contaminated by toxic soil – that’s been excavated for Toronto’s construction boom.

And the Toronto Star report says often, the exact location of where the soil is being dumped – is a mystery.

The report also says the Ontario government doesn’t track where construction soil is discarded – until locations are “discovered accidentaly.”

The poisoned soil contains dangerous materials such as petroleum and heavy metals.

The newspaper adds that the Ontario Waste Management Association has seen a decrease in the number of trucks hauling dirt to special landfill sites – created to manage toxic soil.

Environment Minister Glen Murray told the Star that better controls are needed – and the issue is at the “top of environmental and economic concerns” in Ontario.

The province and several agencies weren’t able to provide soil location details from huge construction projects – when asked by the newspaper.