Alberta Energy Minister Ken Hughes ordered the safety assessment last summer following three oil pipeline spills, including one that polluted part of the pristine Red Deer River.
An engineering firm completed the technical report last fall and presented the findings to the government, which sent the findings to the Energy Resources Conservation Board for a review that was to be completed by March 31.
"It is long overdue for this report to be made public," NDP environment critic Rachel Notley said Tuesday.
"Albertans have a right to know about their safety and their environmental health. This government has a duty to Albertans to be upfront about the safety of the system."
Notley also released documents that she suggests show the province is requiring fewer inspections of new pipelines.
Alberta has more than 400,000 kilometres of provincially regulated oil and natural gas lines — many of them up to 40 or 50 years old. There are also federally regulated pipelines that cross provincial boundaries or the U.S. border.
Last fall, the government said it wanted to broaden the safety review to include input from the public.
Hughes said Tuesday there is still no date for when the report will be released. He added only that it would be soon.
The public won't be asked for comments until after the report is released.
"I believe that the industry has already undertaken a lot of steps to address any concerns that might have come to their attention over the past year," Hughes said.
"Certainly if there are regulatory changes, that will be part of the discourse once we release the report."
Hughes did not give any examples of changes the industry has made in the last year to make pipelines safer.
Last summer, more than 50 environmental, First Nations, land rights and union groups called for public input into the pipeline safety review.
They made the call after a Plains Midstream Canada pipeline leaked about 475,000 litres of oil into the Red Deer River near Sundre. The river is a major drinking water source for central Alberta.
Last month, the provincial government charged Plains Midstream with three environmental offences for an April 2011 pipeline breach in northwest Alberta that released 4.5 million litres of oil.
The government has said the goal of the safety review is to determine whether the pipeline industry is performing to best world standards.
Hughes called the NDP information about fewer pipeline inspections by Alberta's energy regulator incomplete and incorrect.
He said the Energy Resources Conservation Board is "aggressive" about pipeline inspections.
"The government doesn't tell the ERCB how many inspectors to have and how many inspections to do," he said. "The ERCB manages their inspections according to any current concerns that they have."
Earlier this year, the board harshly criticized Plains over the April 2011 spill. It said the company did a poor job assessing the risks associated with the pipeline, failed to maintain it properly and didn't have a sufficient response plan in case of problems.
The board added that earlier repairs probably contributed to the leak and it faulted the company for having inadequately trained staff and ineffective supervision.
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