By Elizabeth McGowan, InsideClimate News
1969: Pipeline 6B installed.
1999: Enbridge begins carrying diluted bitumen from Alberta on Pipeline 6B, part of the company’s Lakehead system.
2008: An internal Enbridge inspection identifies 140 corrosion defects on 6B.
2009: Another internal Enbridge inspection identifies 250 more corrosion defects on 6B.
2009: Enbridge tells PHMSA it will reduce pumping pressure along 6B while deciding whether to repair or replace the line.
July 2010: Enbridge in midst of dig-and-repair program on 6B in Marshall area and elsewhere.
July 15, 2010: Enbridge seeks permission from PHMSA to continue operating 6B at reduced pressure for another 2 ½ years.
July 15, 2010: Enbridge official tells a congressional subcommittee the company’s response time to a leak can be “almost instantaneous.”