MONTREAL — As the crack of explosions broke the early-morning quiet and clouds of black smoke billowed above Lac-Mégantic on July 6, millions of litres of crude oil gushed along the ground.
Some of the oil fuelled the raging fire that erupted after a72-car train derailed, blazing through Lac-Mégantic and eventually making its way to the surface of the lake that gives the town its name. Some of the oil evaporated in the fires that burned for two days, creating a plume of smoke that spread east toward the U.S. border. And some of the oil — hundreds of thousands of litres of it — flooded the manholes around the crash site, overwhelming the town’s sewer system.
In the chaotic days after the accident, as emergency workers first searched for survivors and then, their remains, it wasn’t clear what impact the derailment had on the environment.
But six months after the accident, a more detailed picture is emerging about the oil carried in the derailed train, how and where it spilled, and the efforts made to try to stop it from causing widespread environmental damage in the town and nearby lake and river.
THE SPILL
The Montreal Maine & Atlantic Railway train that derailed in Lac-Mégantic was carrying 7.6 million litres of crude oil. Of the 72 cars in the train, only nine did not spill any of their contents. Nearly 6 million litres of oil spilled out of the other cars that night.
The catastrophic accident caused damage as far as half a kilometre from the crash site in the heart of downtown Lac-Mégantic, according to a report on soil contamination prepared for the Quebec government. Oil spread even farther — more than 100 kilometres downstream on the nearby Chaudière River.
Some of the oil — it’s not clear how much — fuelled the ensuing fire that swept through the downtown core, destroying 40 buildings and the urban infrastructure in its path. The fire melted siding on buildings, destroyed cars, razed houses and businesses, twisted metal fences and left burned trees devoid of any leaves in it wake.
As the oil burned, contaminants — including benzene, toluene, ethylene, xylene, polycyclic aromatic hydrocarbons and volatile organic compounds — were released, air-quality testing showed.
A small amount of oil evaporated without being burned, according to the 853-page soil-contamination report prepared by Montreal-based Golder Associates.
Quebec’s Environment Department said most of the spilled oil burned, though it can’t quantify the amount.
But “hundreds of thousands” of litres of oil emptied out onto the ground, the Golder report said.
It spilled into the streets, rushing toward the manhole covers near the crash site, and deluging Lac-Mégantic’s sewer system. The bowl-like shape of Lac-Mégantic allowed the oil to converge downtown, the Golder report said.
Burning oil made its way by land toward the lake, the inferno cracking rocks along the shoreline. Strong winds blew the burning oil back toward the rocky shoreline and the town’s Parc des Vétérans.
Blazing oil swept through the sewer system, reaching the town’s water-treatment centre and emptying into the lake and nearby Chaudière River. Emergency workers tried desperately to stop the oil from travelling through the sewers to the lake and river, closing off parts of the sewer network and storm drains to prevent the oil from draining farther downhill to the two waterways, the Golder report said.
Oil was pumped out of the sewers to prevent it from spreading and to stop it from reversing toward the buildings. Steps were also taken to prevent it from emptying into the stormwater drains in the impact zone.
In the five days after the accident, emergency crews worked to stop any remaining oil from spilling out of the tanker cars and installed more than three kilometres of booms containing absorbent products along the Chaudière, around the Lac-Mégantic marina, and along the shoreline near Parc des Vétérans.
Despite their efforts, oil found its way to the river. Samples taken a week after the crash in Charny, a town 130 kilometres from Lac-Mégantic, showed the presence of compounds found in crude oil.
Because of toxic fumes — the volatile portions of some of the components of crude oil, including benzene and toluene — some workers were not able to work in the area around the crash site in the days after the accident. Air quality in the area returned to acceptable levels by July 10, four days after the accident, Quebec’s Environment Department said.
THE CLEANUP
It was only about two weeks after the accident that environmental cleanup companies were allowed into the zone where the train crashed to begin digging trenches to collect oil, to pump out oil and contaminated water, and to begin to evaluate the volume and extent of the spill.
On July 24, work began to determine which buildings in the town had been contaminated during the accident, and what steps should be taken to deal with them.
Sampling and testing done during the summer found oil in the soil, and in the gravel and soil located around underground infrastructure such as building foundations and sewer pipes. The area with the most contaminated soil — about 69,000 cubic metres, enough to fill 27.5 Olympic-size swimming pools — was around the crash site itself, the Golder report said.
Most of the oil that made its way to the lake and river went through the sewer network and the soil around the pipes, said Jean-François Ouellet of the Environment Department. A significant portion of the oil that has been collected since the accident came from the town’s sewer system, he said.
Another area of soil contamination in Lac-Mégantic was where the fire burned. There, an estimated 12,000 to 22,000 cubic metres of soil is contaminated, the Golder report said.
About one-third of the soil that will have to be decontaminated is around the sewer pipes and building foundations, along the shore in Parc des Vétérans, and in two other areas of the town, the report said.
Since the accident, about 1,200 soil samples have been analyzed, along with 127 water and liquid samples taken from 24 collection sites in Lac-Mégantic, the report said.
Oil was found in several areas, including in collection trenches that were dug near the crash site and burned zones, as well as in recovery wells near the gravel around sewer pipes, and near the lakeshore. The report said large pools of oil were not found in underground water, probably due to the low permeability of the clay soil in the area.
Glycols and other chemicals used to fight the fires were also found in the soil samples in the area around the crash site and the burned part of downtown, the report said.
Some of the soil samples found high levels of sulphur in the surface layer of soil in the zone around the crash site, but it wasn’t clear if that was because of industrial activity that had previously taken place in the area, or if it was due to the spilled oil, the report said.
By the end of October, 75,000 cubic metres of soil had been excavated from Lac-Mégantic and moved to a storage and treatment site that had been built about two kilometres outside town. The province wants soil decontamination work to begin by the end of March, with all the soil decontaminated or stored by mid-December.
Quebec’s Environment Department said that some of that soil, once decontaminated, might be returned to Lac-Mégantic if it meets the province’s highest standards for contaminated soil rehabilitation.
Soil that is not returned to Lac-Mégantic will have to be disposed of at an authorized site, the Environment Department said. All the soil removed from Lac-Mégantic that is not returned to the town must be decontaminated and disposed of within three years of the contract for the work being signed.
The Environment Department said the soil decontamination work alone could cost between $75 million and $100 million.
As for the two waterways affected by the accident, 600 samples have been taken from Lake Mégantic and the Chaudière River, the Environment Department said. Although the level of contamination has decreased since the summer, some parts of the river are still contaminated.
While some environmental groups have called on the government to dredge the bottom of the river to remove oil from the riverbed, cleanup operations are instead being done in targeted areas. That’s to prevent irreparable damage to the river ecosystem, the Environment Department said. More than 600 samples of sand and pebbles have been collected in order to assess the ongoing cleanup operations and identify areas where pollutants may have collected, Ouellet said. He noted that analyzing the river sediment samples is a complex process, but the department expects to have final reports by March.
During the winter, a committee will review the effectiveness of the work that has been done on the river, and devise a river-management plan by spring. That plan will address the long-term effects of the oil spill on the water, fish and other wildlife in the river, and monitor the effect spring thaws could have on oil in the riverbed, Ouellet said.
While a few dead fish and birds were found after the derailment, the Environment Department said there was little effect on flora and fauna in the area. To monitor the long-term impact on wildlife and plants, the department collected fish from the river during the fall and will test them in the coming months, Ouellet said.
UNKNOWNS
The oil that’s in the soil, along the lakeshore and on the bottom of the Chaudière River, began its journey to Quebec 2,700 kilometres away, in North Dakota. The product of several different wells in North Dakota’s Bakken oilfields, the crude was on its way to an Irving refinery in St. John, N.B., when the train derailed in Lac-Mégantic.
Tests done on oil samples taken by Canada’s Transportation Safety Board from nine of the tanker cars that did not leak found the crude was more volatile — and more explosive — than conventional crude oil. The “fierce fire” and violent explosions that followed the derailment were “abnormal” for crude oil, according to TSB investigators.
Questions have been raised about whether the crude had higher-than-usual levels of hydrogen sulphide or benzene, both highly flammable. Some Bakken oil has been found to have extremely high levels of hydrogen sulphide.
On Monday, another oil train carrying crude oil crashed and burst into flames in North Dakota, with explosions that looked very similar to those in Lac-Mégantic.
The TSB initially analyzed the oil samples only to determine its flash point and boiling point, said TSB spokesperson Julie Leroux. Other analysis of the samples is ongoing, as is the crash investigation, she said.
“It would be irresponsible to release information piecemeal,” Leroux said. “All tests must be analyzed and I can assure you our comprehensive investigation report will address all aspects of the accident.”
Leroux said she could not say when the TSB report will be completed. The last time the TSB provided new information from its investigation was in September.
While a clearer picture is beginning to emerge of the extent of the oil contamination in Lac-Mégantic, many questions remain unanswered. Even six months after the accident, it’s not clear how much oil made its way into the ground, the lake and the river and how much has been recovered in cleanup operations.
Quebec’s Environment Department has estimated 100,000 litres of oil spilled into the Chaudière River. While the department said that 457,500 litres of oil had been collected from the oily water pumped from Lake Mégantic by July 22, it is unsure how much oil was in the 46 million litres of oily water that has been pumped out of the lake and river since the accident.
The oil from the train cars that did not spill during the accident was collected by Irving, Ouellet said, and the rest was taken to disposal sites in Ontario and Nova Scotia.
While the crash itself was over in a matter of seconds, the cleanup is expected to take months, and possibly even years. The Quebec government estimates that restoring Lac-Mégantic to pre-accident condition will cost at least $200 million. Ottawa has pledged to pay $95 million.
Quebec has ordered six companies — including Canadian Pacific and MMA — to assume the cleanup costs, which the government is paying. Because that order is being challenged in court, the Environment Department said it could not say how much the cleanup has cost so far.
mbeaudin@montrealgazette.com
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