Keith Matheny

Detroit Free Press

Editor's note: This story has been updated to add more detail to Enbridge's response.

Despite Canadian oil transport giant Enbridge's assertions that it had cleaned up all but one of the five barrels of oil they said leaked from a pipeline in the Hiawatha National Forest in the Upper Peninsula around 1980, contaminated soil and groundwater persisted at the site for more than three decades.

And now, so do the questions.

Enbridge contractors revisited the spill site in 2011 and found high levels of harmful, petroleum-related chemicals in forest land and the water table beneath it. They removed 825 tons of soil from the site and requested permission from the U.S. Forest Service to install groundwater monitoring wells the following year.

Though Enbridge says it notified authorities of the spill when it happened, Forest Service officials say they didn't hear about it until 2012 when the company requested the water monitoring. They question Enbridge's delayed reaction to discovering and cleaning up the Hiawatha contamination, as well as the delay in informing forest officials.

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Additionally, and in light of the heavy remediation Enbridge says it already has done, the Forest Service and environmental groups also are now questioning the full extent of the contamination and whether perhaps more oil than has been reported was actually spilled. Though recent groundwater tests have not detected contamination, U.S. Forest Service officials say they "do not have enough information to evaluate the extent of the spill and its effects at this time."

Either Enbridge knew about the extent of the contamination in the national forest for more than 30 years and didn't clean it up; or it didn't know about the spill's effects for more than three decades — and either answer is troubling, said David Holtz, chairman of the Michigan Chapter of the nonprofit environmental group Sierra Club.

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The Hiawatha spill occurred on Enbridge's Line 5, a 30-inch transmission line carrying nearly 23 million gallons of crude oil and natural gas liquids, such as propane, daily through Michigan's Upper and Lower Peninsulas and on to Sarnia, Ontario. It's the same Line 5 whose twin, 63-year-old pipelines running underwater through the Straits of Mackinac has caused a public outcry and state review over a leak's potential to damage the Great Lakes and shoreline communities.

The long-ago Hiawatha spill, and how Enbridge has handled it, has relevance to the debate today about the pipelines in the Straits, Holtz said — calling into question the company's ability to understand the scope of, and effectively respond to, spills along its pipelines.

The 825 tons of soil excavated by Enbridge officials from the Hiawatha National Forest contamination site were disposed of in a Delta County landfill in May 2012, company officials informed the Forest Service later that year. So the soil can't be tested. Enbridge spokesman Ryan Duffy, however, said much of that soil was removed as part of a simultaneous project to install a new valve on Line 5.

"I'm not a scientist; I can't explain the physics of how one barrel of oil contaminates 825 tons of soil and contaminates groundwater," Holtz said. "But it doesn't pass the smell test — or the spill test, in this case.

And "they effectively buried the oil spill evidence in a landfill," he said.

The spill occurred in the section of the forest between Escanaba and Manistique, in Delta County's Nahma Township.

"An oil release associated with a 3-inch crack in a longitudinal weld in the pipeline was observed during a routine inspection in the 1970s and an estimated five barrels of crude were released. Four barrels of crude were recovered and one barrel was lost," Enbridge officials stated in an environmental assessment provided to the Forest Service in 2012, as part of a request to install groundwater monitoring wells in the Hiawatha National Forest.

But Duffy, in an e-mailed response to Free Press inquiries, said the spill was discovered in late July 1980.

"Our detailed records show that Enbridge (then known as Lakehead Pipe Line Company, Inc.) acted quickly on July 28, 1980, as soon as a release of approximately five barrels of light crude oil in the Hiawatha National Forest was detected," Duffy stated.

Duffy stated Enbridge officials notified the Michigan Department of Natural Resources — which then included duties that are now assigned to the state Department of Environmental Quality — on July 28, 1980, and the Michigan Public Service Commission and U.S. Forest Service — "although there was no requirement to do so" — the next day.

Duffy said Enbridge's records show the names of three officials and the times at which they were contacted in 1980. Duffy provided the names and times to the Free Press. The agencies have been unable to verify the officials' names or the reports.

"The spill was cleaned up following all the standards and requirements of that time," he stated.

But U.S. Forest Service officials at the Hiawatha National Forest, who also responded to Free Press inquiries via e-mail, stated: "We believe the Forest Service was first made aware of this spill in August 2012," adding, "We don't know the reason for the delay in notification and cleanup."

Duffy didn't specify why Enbridge chose to look at the area of the spill more than three decades later, in 2011.

"When we returned to the site in 2011 for a valve replacement project, a decision was made to check for any remaining impacts related to the 1980 release," he stated.

As Coleman Engineering conducted tests at the site on July 27, 2011, three soil samples and two of four groundwater samples "exceeded cleanup criteria" for volatile organic compounds under the Michigan Natural Resources and Environmental Protection Act, according to Enbridge's environmental analysis presented to the Forest Service at the time groundwater monitoring wells were requested. Three groundwater samples also exceeded DEQ cleanup criteria for polynuclear aromatics, or PNAs.

Both volatile organic compounds and PNAs are known carcinogens. Though campsites exist not far from the spill site, it is unlikely any human exposures occurred at prolonged enough or significant enough levels to cause harm in the remote forest area.

Coleman returned to the site more than nine months later, in May 2012, to conduct further soil sample tests and attempt to "assess the extent and magnitude" of the oil spill, Enbridge's environmental analysis states. "Seven soil samples exhibited results which exceeded MDEQ Cleanup Criteria," the analysis states.

That same month, according to the analysis, Enbridge's operations department "excavated contaminated soils to facilitate remedial work on the pipeline. Approximately 825 tons of excavated soils were transported to the Delta County Landfill for disposal."

That Enbridge was able to identify the volume of the spill at five barrels in 1980 suggests an understanding of the spill's scope that doesn't correlate with finding soil and groundwater contamination many years later, Holtz said. "It would be interesting to know how Enbridge arrived at that estimate," he said.

And Hiawatha officials don't necessarily accept that figure.

"The Forest Service does not have enough information to evaluate the extent of the spill and its effects at this time," they stated.

The groundwater monitoring wells were installed late last summer, Forest Service officials stated. Contaminants were not detected, "which means dissolved contaminants are confined to the trench area and the right-of-way," they stated. Subsequent test results from October and December also showed no contamination. The Forest Service is awaiting results from a March sampling as well.

"After four quarters of sampling, Enbridge will submit all reports to MDEQ for review and approval, and (will be) requesting an audit for no further action," Forest Service officials stated.

Enbridge's special-use permit with the forest service allowing the pipeline to run through the Hiawatha National Forest calls for the company to "comply with the regulations of the Department of Agriculture and all federal, state, county and municipal laws, ordinances or regulations." It also requires that the company "exercise diligence in protecting from damage the land and property of the United States, the property covered by and used in connection with this permit."

Penalties, or a bill for damage to the national forest resources, could eventually be coming Enbridge's way, per the terms of the special use permit. But those discussions with Enbridge officials have not yet taken place.

"We are currently focused on learning the extent of the impact via the monitoring wells," Forest Service officials stated. "Given the time lapse and the fact that the spill occurred under an old permit, we want to make an informed decision to protect the resource. As more information becomes available, we will take further action."

Said Duffy: "Enbridge policy and procedure demands compliance with all federal, state, and local regulations, and we have been in full compliance with regards to our permits and easement through the Hiawatha National Forest."

The Forest Service should conduct an environmental assessment of Line 5 in all of the national forests the pipeline runs through in Michigan, Holtz said, including Hiawatha, the Ottawa National Forest in the far western Upper Peninsula, and the Huron-Manistee National Forest in northeast Lower Michigan.

"Trust is earned, and if anything, what Enbridge has earned is our skepticism of the safety of their pipelines and how they handle oil spills," he said.

Contact Keith Matheny: 313-222-5021 or kmatheny@freepress.com. Follow on Twitter @keithmatheny.