About 10 per cent of Alberta’s 1,500 abandoned oil and gas wells in urban areas are leaking methane, in some cases at levels that create the risk of health damage and explosions, according to an unreleased 2016 report.

The unpublished study by the Alberta Energy Regulator, obtained by The Tyee, identified 335 urban wells that were “believed to be in close proximity to surface developments (houses, airports, business, etc.).”

The 33-page study found that 36 of the abandoned wells were leaking methane. Nine of those wells were leaking at a level that Alberta Health says poses a risk of neurological damage to nearby residents.

Six of them were leaking methane at more than 10,000 parts per million (ppm), a level deemed “life threatening” by Alberta Health.

According to a 2015 Alberta Health document titled “Methane from Leaking Abandoned Wells: Health and Safety Concerns” also obtained by The Tyee, leaks of 1,000 ppm could result in neurological effects. Leaks above 10,000 ppm pose explosion risks and should prompt “emergency evacuation,” the Alberta Health report said.

The Alberta government has not released the health and safety methane document. When The Tyee asked for a copy two months ago, ministry press secretary Laura Ehrkamp said officials couldn’t find it.

The methane leakage study was prompted by new regulations in 2014 that directed industry to locate and test abandoned wells that may pose a risk to communities.

It found that six wells that exceeded the emergency evacuation threshold of 10,000 ppm were outside buildings. Three other hazardous wells had “methane leakage inside buildings.”

In addition the report noted another 53 abandoned wells out of the 1,500 that had been identified as “higher risk” because of sour gas or acid content. “Licensees were directed to locate and test these wells,” the report says. There was no information on the results.

Although leaking methane from wells often travels with well-known public health hazards such as benzene, toluene, xylene and hydrogen sulfide (a potent neurotoxin), the AER study only measured methane.

The methane toxicity study, never released to the public, was completed in November 2016. Both the AER and Alberta Health said they were still reviewing the data.

Ryan Bartlett, a senior public relations advisor with the AER, said the agency “had conducted a screening level assessment for methane exposure thresholds on leaking abandoned wells in urban centres and is referring nine wells to Alberta Health to determine if there are potential human health impacts and to determine what actions are required to protect public safety.”

Many of the wells with the worst leaks were located in Medicine Hat, where Alberta’s natural gas boom began nearly 100 years ago. The city still owns and operates more than 4,000 gas wells.

One Medicine Hat well site was leaking 70,000 ppm of methane while another leak under an abandoned motel had forced the construction of a venting system.

In another case methane readings inside a church kitchen were 2,550 ppm, two-and-a-half times the level that could cause neurological effects.

Bradley Maynes, general manager of Natural Gas and Petroleum Resources for Medicine Hat, said he hadn’t seen the AER study but was well aware of the leaking wells.

“The city monitors methane anomalies including assessing levels in nearby buildings if necessary,” said Maynes.

The AER only requires a five-metre setback from old or abandoned wells in urban areas. That does not provide enough room for service crews to enter and fix leaking wells.

Alberta Health press secretary Timothy Wilson said the ministry was “reviewing the cases where these thresholds were exceeded to determine potential human health risk and what actions are required to protect public safety.”

Approximately 1,100 abandoned wells in cities like Edmonton, Lethbridge, Medicine Hat, Airdrie and Calgary “still need to be located and tested for leakage,” added the AER report.

Based on the testing of just 338 wells, the study estimated that 17,000 out of 170,000 abandoned wells in rural Alberta are leaking methane and that leaks at 3,400 wells could pose a risk to the public.

“These estimates are very approximate and only through ground truthing and methane testing will true risks become apparent,” warned the report.

Anthony Ingraffea, the Dwight C. Baum professor of Engineering and an expert on fracking and leaking wells at Cornell University, said the AER report added more ammunition to the argument that abandoned wells might be one of the key sources of rising methane atmospheric levels on the continent.

“Let’s suppose that that statistic of two per cent significant leakers translates to the rest of the country, and to the U.S for over a million abandoned wells,” Ingraffea said. “That means more than 20,000 leaking wells at 500 times natural background level, at least, some at 5,000 times natural background level of about 1.9 ppm.”

“When will the public be advised of the emergency conditions that exist near the urban center acute wells?” asked Ingraffea.

Alberta Health’s Wilson didn’t directly answer a question about whether the ministry had a protocol for dealing with leaking abandoned wells in urban neighborhoods.

“Alberta Health reviews information provided by the AER to determine if there are any human health risks, and routinely shares this information with Alberta Health Services and Health Canada if a First Nation is involved,” he said in an emailed response.

According to another 2016 report for Natural Resources Canada, methane leaks from active or abandoned oil and gas wells pose “a serious threat to the environment and public safety.”

The highly flammable gas can contaminate groundwater, accumulate in buildings and pose an explosion risk, and contribute to greenhouse gas emissions.

Leaks from oil and gas wells have caused serious explosions throughout North America, including an April incident in Colorado that killed two people and demolished a home. In that case methane leaked from an abandoned pipeline still connected to a gas well and accumulated in the basement of a home.

The report sheds more light on the scale of the province’s largest unfunded environmental liability, the $30 billion to $300 billion cost of cleaning up old petroleum facilities, including 90,000 inactive wells, pipelines and thousands of orphaned wells or wells abandoned by their bankrupt owners.

According to Global News, more than 22 million metres of aging well infrastructure has been buried in the province over the last 100 years.

That’s enough pipe and wellbores to reach the height of Mount Everest 2,500 times. Most sites cost almost $200,000 to clean up; some can cost millions.

In addition little is known about methane leakage rates at 170,000 abandoned wells that were often sealed improperly or with concrete that degrades over time.

The hazard is real and toxic. Inactive and abandoned wells can leak pollutants, including methane and brine, as well as heavy metals and naturally occurring radioactive substances; these pollutants may contaminate groundwater, surface water, or, in the case of methane, be released into the atmosphere.

In one notable Alberta case a gas leak from an abandoned well in Calmar, a small town southwest of Edmonton, forced the demolition of five homes in 2010.

Imperial Oil, which owned the leaking well, asked residents to leave the area repeatedly in 2013 and 2015 while it spent millions trying to fix the leak. But the gas is still leaking.

Local residents in Calmar still argue that the province needs tougher legislation to ensure that more homes and buildings do not end up next to leaking abandoned wells, and that the province’s 170,000 abandoned wells be systematically checked for leaks every year especially if they are located near homes or livestock.

Studies show that 50 per cent of all well repair jobs often fail to control the source of leaking methane.

Canada’s Methane Leakage Massively Under-reported, Studies Find read more

Methane leaks from abandoned and active oil and gas wells have caused a string of explosions across North America, including in Pennsylvania, Colorado and Wyoming, New Mexico and Alberta.

In 2006 accumulating gases including propane and ethane blew up a pump house at a farm in Central Alberta and hospitalized farmer Bruce Jack along with two workers.

A 2011 study by consultants Alberta Innovates, which was never made public, concluded that similarities in the “signatures of some of the gases in the Jack well with the gases in some of the energy wells in the area may indicate similar geological origins, but the results were not conclusive in identifying the source, pathway or method of introduction of the thermogenic gas to the Jack well.”

Four wells near the Jack farm tested positive for gas migration or leaks.

The Jacks sued an energy company and took a very small settlement “just to end it all” but did not sign a confidentially release agreement as is customary in Alberta.*

Researchers estimate that seven to 19 per cent of producing wells completed between 2005 and 2007 have been affected by gas migration along the casing annulus, while nine to 28 per cent showed gas leakage through the surface casing. The annulus is the space between the pipe and drilled rock.

A 2016 study completed for Natural Resources Canada explained that “abandoned oil and gas wells may develop wellbore leakage either over time or relatively soon after abandonment” due to poor cement jobs or poor regulation of the plugging process.

Alberta has among the most detailed and comprehensive reporting requirements for leaking wells out of seven major oil and gas jurisdictions in North America.

But a 2016 report for Natural Resources Canada noted flaws in the system.

“Even in Alberta, with the best reporting standards, there is no third party monitoring of well bore leakage required,” the report noted. “Being the industry is not financially or operationally motivated to report leakage, information... about the wellbore leakage is suspect.”

* A correction was made on June 28, 2017 at 1 p.m.