For more than a month, crews have been mopping up the five million litres of bitumen, water and sand that leaked at Nexen's Long Lake operation south of Fort McMurray.
But the First Nation that sits about 10 kilometres from the spill site wants the company to share more information about its water testing.
Byron Bates, a councillor with the Fort McMurray First Nation, says it has sent two letters to Nexen requesting data from the company, but without success.
"We just hope for a better working relationship with Nexen where they share their test data, so that we can have our professionals go over it," he said.
"Our main concern is what happened to the processed water when the pipeline ruptured and where did it go. You know, it got into the muskeg, but where did it go from there? It could have travelled to the lake nearby."
'Endeavouring to share'
Some of the data and information will not be available until the investigation is complete and details are verified, said Nexen spokeswoman Diane Kossman in a written statement.
"We're endeavouring to share as much information as possible, including comprehensive details that are posted regularly to our website," she said.
"Our focus remains on safety, minimizing environmental impact [including continuing the extensive clean-up activities at the spill site] and conducting our in-depth investigation to determine the root cause of the spill."
Meanwhile, the Alberta Energy Regulator (AER) continues its own investigation.
AER public affairs adviser Ryan Bartlett says Nexen sends reports to the regulator three times a week, and its own staff are at the site regularly gathering evidence and trying to determine the root cause of the leak.
"The goal of our investigation is to confirm whether or not a violation has occurred and then to assess whether or not enforcement action is warranted," he said.
"We'll look into construction practices. We'll look into operating practices and the monitoring of the line from the company."
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