Calgary-based Enbridge is coming under fire for a spill in Michigan more than two years ago.  National Transportation Safety Board chairwoman Deborah Hersman handled the situation like "the Keystone Kops".  She says it took more than 17-hours for staff to respond to a rupture in southern Michigan.  She says, instead of stopping the flow, staff twice pumped more crude into the ruptured line, representing about 81% of the total release.  More than three-million litres of crude spilled into nearby wetlands, Talmadge Creek and the Kalamazoo River.  Hersman says poor regulatory oversight by Enbridge and Hazardous Materials staff was also to blame.