The Financial Post reports in its Thursday, July 17, edition that Enbridge has warned about the possibility of an "attack" on one of its pipelines. The Post's Jeff Lewis writes that the warning was contained in a redacted emergency response plan filed with the National Energy Board tied to the company's Line 9 reversal and expansion. An un-redacted version was hand delivered to the NEB's Calgary offices and shared with first responders on the 600-kilometre pipeline route. "Information marked 'security' has been redacted as this information could be used by those with technical knowledge to attack the Enbridge system," Enbridge told regulators. "Public knowledge of where to attack the leak detection system would impair the security of the system and the pipeline." Industry experts say redacting information for security or commercial reasons is common practice among pipeline companies when documents are submitted to public registries. "It's the same thing with offshore drilling or even onshore drilling," says former NEB chairman Gaetan Caron. The spectre of an attack comes as efforts to expand markets for Alberta's oil sands production face intense resistance from environmentalists and first nations.