Nova Scotia's Colchester County is blocking a company’s plan to dump fracking waste water in the sewer in Debert, a system that is connected to the Bay of Fundy.
An appeal committee has unanimously rejected the idea Thursday.
The company, Atlantic Industrial Services, wanted permission to get rid of 4.5 million litres of fracking waste. The water is from drilling operations several years ago near Kennetcook in East Hants County.
This ruling overturns a decision two months ago.
Committee members say there are too many unknowns to allow the disposal of the waste, with no independent verification of which chemicals are going down the drain.
In its decision, the county writes: "it is not the role of the Municipality to allow the Bay of Fundy to be a petri dish for fracking wastewater."
The provincial government gave the plan partial approval, while the company argued the water will meet federal guidelines.
But the committee reviewing the project on behalf of the county said important information was missing, specifically, the chemical composition of the fracking water.
"The river and the Bay of Fundy are too important to permit such discharge on an experimental basis."
The county said it wanted to hear independent analysis of how other areas dealt with similar situations.
"It is the Municipality’s role to ensure the environment is protected now and in the future," the decision said. "In that role, it must exercise caution to act only when the information is complete."
In September, the company told CBC News that "Nova Scotia is naturally high in many normally occurring radioactive materials." It said the water would not be released until it met national guidelines.