TransCanada, the company behind the recently rejected Keystone XL oil pipeline, made the comments after a report last week from Canada's transportation safety watchdog on the gas line rupture.

The Transportation Safety Board of Canada said inadequate inspections and oversight by TransCanada were factors in the accident on its North Central Corridor line near the oil sands hub of Fort McMurray, Alberta.

TransCanada had overstated the pressure rating of the pipeline and was running it beyond its design limits, the report said. It added that inadequate inspections led the company to use "information from the manufacturing design drawings instead of a direct measurement."

TransCanada spokesman Davis Sheremata said that a miscommunication with the contractors that built the pipeline component which failed was to blame.

He said TransCanada conducted the required repairs and was using the incident as a "learning opportunity" to improve its inspection program.

Evan Vokes, a former TransCanada engineer, said he warned the industry regulator, the National Energy Board (NEB), in a written complaint from May 2012 about the pipeline component that failed, among other allegations.

The NEB, which later confirmed some of Vokes' warnings in a 2014 report, said in 2012 that it was investigating the allegations but that it saw no immediate threat to public safety or the environment.

The NEB did not immediately respond to questions about the report.

The rupture created a crater about 50 metres (165 feet) long, sending fragments up to 130 metres away on a traditional Cree hunting land, the report said. There were no nearby homes, but the report also said the rupture was within 250 metres of a hunting cabin and affected two oil sands customers.

The report comes as Canada's newly elected Liberal government pledges to review federal oversight of resource development, addressing criticism from some environmental and landowner groups that the former Conservative government was too close to the industry.

(Reporting by Mike De Souza; Editing by Lisa Shumaker)

By Mike De Souza