Two years ago, Michigan suffered the largest, most destructive and most expensive onshore oil disaster in U.S. history when the Enbridge oil pipeline company spilled more than a million gallons of tar sands into the Kalamazoo River.

New Englanders have a lot to learn from that story before we allow toxic tar sands oil to be pumped across northern New England and Maine.

Despite their denials, the Canadian corporation Enbridge Inc. appears to be reviving a plan, called Trailbreaker, to transport tar sands through some of the most important natural and cultural landscapes in eastern Canada and Vermont, New Hampshire and Maine.

Their plan would reverse the direction of oil flowing through about 750 miles of existing pipelines.

The route would run from Ontario and Quebec to Portland Harbor in Casco Bay, where tar sands oil would be exported by tanker.

Enbridge has taken the first step in their plan by filing a permit application with Canada’s National Energy Board.

We should take heed of the lessons of Enbridge’s Kalamazoo spill before we allow them to implement this plan.

Instead of conventional oil, Enbridge’s pipeline would carry Canadian tar sands crude.

This is an important distinction.

Tar sands have been called the dirtiest oil on the planet because of its impact on climate disruption.

But its impact on a river and on a community is much more gruesome and immediate.

Tar sands are thick like asphalt.

To pump it through a pipe it must be diluted with lighter toxic chemicals.

The corrosive tar sands, which are pumped at much higher pressure and temperature than conventional oil, are more likely to rupture a steel pipeline.

And when that happens, the heavy tar sands sink in a river, sticking to sediment and making cleanup extraordinarily difficult and expensive.

After a two-year, $800 million cleanup effort, Enbridge estimates that more than 390 acres of the Kalamazoo River remain contaminated.

The immediate health threat of the oil spill was the release of the chemical diluents into the air where they sickened residents.

These diluents include carcinogens and other noxious poisons

In Marshall, Wis., children and staff at a daycare center three-quarters of a mile from the spill experienced severe illness, skin lesions.

They now must live with the unknown threat of long-term health impacts.

Enbridge’s response to the Kalamazoo disaster raises more serious questions and concerns.

The company ignored warnings of a pipeline failure, waiting 17 hours to shut down the pumps while they continued to pump tar sands into the environment from a six-and-half foot crack in the pipeline.

They missed it until a gas company employee finally alerted them to the problem.

Especially troubling is that Enbridge knew about flaws in the pipe for five years, but used bureaucratic maneuvering to put off repairs.

And then they delayed alerting public health officials, emergency responders and local families that what they had spilled was not conventional crude oil but highly toxic tar sands.

The Kalamazoo disaster is the story of a complete failure of a company and public officials to protect public health.

Today, the Kalamazoo River remains contaminated with no new pipeline safety standards, no real changes to improve safety and no reason at all to believe that a major tar sands oil disaster isn’t in the cards for any New England river crossed by one of these pipelines.

For Maine, that means risk to numerous clean water bodies, including the Androscoggin River, Casco Bay and Sebago Lake, the drinking water source for greater Portland.

This week more than twenty “We are the Kalamazoo” events were held in Maine and around the nation.

These commemorations of the Enbridge disaster will culminate on Sunday with a demonstration at the annual Conference of New England Governors and Eastern Canadian Premiers in Burlington, Vt.

Despite huge fines, cleanup costs and increasing public opposition, Enbridge has not learned from their grave mistakes in Michigan.

The people of Michigan are telling their stories because they don’t want them to be ours.

We need a Tar Sands-Free New England.

Glen Brand is chapter director of the Maine Sierra Club.