Michigan's Mysterious Tar-like Rocks

Three years after spill, blobs in river raise questions about bitumen cleanup risks.

By Andrew Nikiforuk 16 Dec 2013 |

Andrew Nikiforuk is a Tyee contributing editor and the writer in residence at the Haig Brown Heritage house in Campbell River. Find his previous Tyee articles here.

[Editor's note: Since publishing this story on Dec. 16 more information about the Kalamazoo tar-like rocks mystery has surfaced. In response we've made some changes to this story, and have published a new one here.]

After Enbridge's Line 6B ruptured in 2010, spilling approximately 30,000 barrels of diluted bitumen (dilbit) into Michigan's Kalamazoo River, 47-year-old Craig Ritter couldn't believe the strange rocks he started to find on the river bottom.

The bizarre formations, the size of volley balls or melons, often resembled giant Easter eggs.

And they lined the bottom of the river downstream of the 51-kilometre-long spill all the way to Lake Michigan.

Ritter, a facility engineer who spends his spare time observing life on the river, suspects the weird looking rocks are the product of the bitumen spill. And he is worried that the waterway, once a haven for nature and playground for locals, has become a toxic "ongoing science project."

It's an experiment British Columbians have reason to closely watch, given pressing questions in this province about what happens to bitumen when it is dumped into flowing fresh water, and whether dispersants normally used in ocean settings help at all, or even make matters worse.

Legacy of diluted bitumen spill

Ritter isn't the only one disturbed by the legacy of Enbridge's oil spill. In particular another phenomenon called "tar patties" also caught the attention of Michigan public health authorities.

In fact their 2012 health report recorded the stubborn presence of oil along the river banks and bottom.

"Some of the oil in the floodplains and riverbank areas weathered and became asphalt-like tiles on the soil. These asphalt-like tiles, also called "tar patties," range from being soft and clay-like to hard, similar to an asphalt parking lot. It is possible that oil may leak out from these tar patties and could get on the skin of people handling them."

And that's just a small part of the puzzling legacy of the costliest onshore oil spill in U.S. history, its price tag topping $1 billion and climbing.

The rupture of the pipeline carrying diluted bitumen sickened hundreds and led Calgary-based firm to buy out some 150 homes along the Kalamazoo River.

The spill just "overwhelmed residents" says Ritter. It also forced an unprecedented and seemingly endless cleanup.

The U.S. Environmental Protection Agency has repeatedly ordered Enbridge back to the contaminated river to dredge and excavate for submerged oil -- even three years after the original accident.

The latest cleanup order must be completed by the end of December. Moreover the project has expanded to include the purchase of the entire Ceresco dam where oil backed up due to the way diluted bitumen behaves in flowing water.

A special kind of mess

Heavy bitumen presents new and unique challenges for policy makers and regulators whose protocols largely deal with cleaning up conventional light oil, a very different petro product.

The Kalamazoo bitumen spill's aftermath is causing many experts to observe that existing laws and policies crafted to deal with conventional oil spills are not only based on outdated science but don't adequately protect exposed workers, the general populace or the environment.

For starters bitumen is just too thick to move through a pipeline and too heavy to float on top of water.

Due to its gooey character, the low-grade crude must be diluted and mixed with solvent-like condensate often produced by the hydraulic fracturing of shale oil and gas deposits. The condensate or diluent, the petroleum equivalent of paint thinner, makes its easier for bitumen to flow through a pipeline. U.S. condensate exports to Canada have grown 1,000 per cent in the last two years.

Most condensates like many petroleum distallites used for hydraulic fracking are highly carcinogenic because they contain benzene and n-hexane.

During the Enbridge spill the volatile and toxic petroleum distillates in the condensate flash evaporated into the air, the fumes making hundreds sick. Meanwhile, the bitumen grew heavy and sank to the river bottom.

In other words dilbit behaved much the same way Imperial Oil's 2002 Material Data Sheet on dilbit said it would: "Product will submerge after a few days of weathering."

The sheet added that, "If allowed by local authorities and environmental agencies, sinking and/or suitable dispersants may be used in unconfined waters."

Dispersants deployed?

Given the tar-like rocks they were turning, Ritter and other citizens along the river wondered: Did Enbridge use dispersants like Corexit deployed during the BP spill in the Gulf of Mexico to sink the bitumen?

Ritter says that he saw companies dumping something that looked like sand into the river during the cleanup and "other stuff that looked like white laundry detergent and stunk like a herbicide."

Or did the diluted bitumen sink from its own weight and form balls in the sediment once the solvent evaporated, creating a cleanup horror show?

So with funding from a local physician Ritter gathered some tar-coloured rocks and sent them off to small lab called Analytical Chemical Testing in Mobile, Alabama for testing earlier this year.

582px version of TarRocks_600px.jpg
Volleyball and melon-sized rocks pulled from the new first public access point installed by Enbridge along the Kalamazoo River, just 450 metres downstream from where the Talmadge Creek enters the river.

While the chemist ran his analysis, the physician did a CT scan of the rocks and found a black substance at the core, then concentric rings of sand and the black substance. The rocks crumbled when rubbed together and left an oily sheen on the water surface.

The lab's chemist Bob Naman also made an interesting discovery: he found some compounds such as 2-butoxyethanol identical to compounds "produced from mixing Corexit compounds with crude oil as in the BP Oil spill of 2010 in the Gulf of Mexico."

"Corexit is a hazardous substance," says Naman.

The controversial dispersant, which behaves like a paint thinner, was designed by Imperial Oil engineers in the 1980s to help wash machinery coated in oil.

It was first used during the 1989 Exxon Valdez disaster and later widely deployed with much controversy in the Gulf of Mexico by boats and planes during the monster BP spill in 2010.

In the Gulf Corexit kept the spill out of public view by breaking apart the oil sheen and pushing the oil below the sea surface, where it poisoned sea life, says Naman.

But there is no record of Enbridge using Corexit, a product largely used for large ocean spills, during their chaotic response to the spill in Michigan.

Riki Ott, a trained marine toxicologist, educator and activist, offers another intriguing reading of the lab findings.

She donned hip waders last summer and accompanied Craig Ritter to the river. She couldn't believe the size of the strange and oily rocks they found everywhere: "They were like lava rocks."

She thinks that paint thinner-like diluents used to thin bitumen for pipeline transport may act and behave a bit like Corexit because diluents are industrial solvents like dispersants.

"These products basically contain petroleum distillates and share some of the same toxic ingredients and properties," adds Ott.

Corrosiveness compounded

In the absence of good science on the behavior of dilbit spills on freshwater, the lab findings raises another important question.

To date all the policies and regulations that government use to respond to freshwater and marine oil spills are based on data on the behavior of light oil, which clearly floats on water.

None are based on the behavior of unconventional hydrocarbons such as diluted bitumen, toxic fracking fluids (diesel and kerosene) or Bakken's fracked oil, which turns out to be much more flammable and explosive than normal crude. A train derailment spilling Bakken crude incinerated 47 people in the Quebec town of Lac-Mégantic earlier this year.

Bakken tight oil and Alberta's bitumen also contain high amounts of hydrogen sulfide, a corrosive substance that is also a deadly neurotoxin.

Recent Alberta research suggests that heating bitumen formations up to 260 degrees in order to pump out the stubborn substance to the surface may change its chemical composition as well as its corrosiveness.

Noted the report: "Crude corrosivity will be influenced by its thermal (heating) history. More work is needed to understand when corrosivity is enhanced." Moreover mixing bad crudes such as bitumen with light crudes "may actually make matters worse due to reducing the content of thermally-labile sulphur and so losing the protection of iron sulphide film formation."

Yet oil spill prevention and response laws and policies are geared for conventional light oil "spills that occur at sea, on the surface, with conventional oil -- and mostly in temperate and tropical areas," explains Ott.

"It is specious to argue that physical containment and recovery, dispersants and bioremediation will work in subarctic and Arctic conditions because of constraints on physical parameters such as weather, temperatures, darkness, ice and more."

"It is also specious to assume that the same laws and policies, based on science conducted for conventional spills, will offer any measure of protection for deepwater spills -- or spills of unconventional oil (dilbit)."

According to the U.S. Environmental Protection Agency, Enbridge initially said its pipeline break poured 819,000 gallons of diluted bitumen into the river.

As of last May, the company had recovered 1.15 million gallons of crude.

Ott adds that there is really no way to respond to an oil spill on a moving river.

"The crude moves and gets backed up behind dams. We're way over our heads in all of this."

Clean up enters fourth year

The U.S. Environmental Protection Agency estimates that "about 180,000 gallons of Line 6B oil (plus or minus 100,000 gallons) remain in the river bottom sediment" and it has ordered Enbridge to remove the recoverable oil (about 12,000-18,000 gallons) by dredging. But EPA to date has said nothing about the tar patties.

Meanwhile health authorities have recommended that, "People should avoid contact with residual oil from the July 2010 Enbridge pipeline release."

The remaining 162,000-168,000 gallons of oil can't be recovered right away without causing significant adverse impacts to the river.

"Instead, it must be carefully monitored and collected over time using traps that gather contaminated sediment. Future oil recovery will depend on whether the crude eventually moves to the areas with these sediment traps."

Ritter says the thing that bothers him most has been the industry's negligence and lack of transparency about the nature and behavior of unconventional hydrocarbons.

"We're living in a science project on this river."

Enbridge, which is proposing to build a series of billion-dollar pipelines carrying dilbit or condensate across North America, says the Line 6B spill was "unprecedented for the company."

The company did not reply to a Tyee email and phone query prior to deadline.

The Tyee apologizes for an error in yesterday's story that has since been corrected:

Tar balls, "tar patties" and tar-coloured rocks are not one and the same. Tar balls or patties, the concern of Michigan health authorities, refer to semi-solid, nearly pure oil. The tar-coloured rocks found in the river look like tar but are rocks containing oil compounds. Many residents suspect the bitumen spill played a role in their formation; scientists suspect they are natural carbonate rocks that have absorbed bitumen.  [Tyee]

Read more: Health, Environment

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