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Provincial authorities still determining health risks from local abandoned wells

Jul 14, 2017 | 11:16 AM

The verdict is still out on whether there are any long term health risks from methane leaks in the Gas City.

According to a draft report from the Alberta Energy Regulator (AER) acquired by the Tyee.com and shared with CHAT News, multiple abandoned wells in the city have been leaking methane at an alarming rate, well over thresholds established by Alberta Health for safe indoor gas levels.

The National Institute for Occupational Safety and Health’s (NIOSH) maximum recommended safe methane concentration for workers during an 8-hour period is 1,000 parts per million (ppm)..

Information from the provincial government outlines that methane is potentially explosive at 50,000 to 150,000 ppm, and causes asphyxiation at 500,000 per million.

Five historical gas wells in the city exceed those limits, based on the data found in the draft report, and one may prove difficult to fix, due to it possibly being covered by a local church.

The well is located in the vicinity of Fifth Avenue Memorial United Church in Medicine Hat’s downtown. According to information found within the municipal archives, the well currently leaking near the building was possibly located just northwest of the original structure.

However, a church expansion in 1957 appears to have been built over the well site.

Fast forwarding to 2017, the municipal government has been testing the well for the past year, and has cordoned off a corner of the church’s exterior due to the high levels of methane found around the building, as well as inside one of it’s kitchens.

The second notable well is near the Veiner Centre along Woodman Avenue, located right behind the sign for the facility, which is currently under renovation.

The draft report states that the leakage rate has been measured at 1,000,000 ppm at the exit of the mitigation structure in place over the well, which is still leaking. The site is currently cordoned-off in the Veiner Centre parking lot, while the facility is renovated.

Reached for comment about the wells, the AER supplied a statement on the topic. In the statement, the agency indicates that the draft report was not finalized.

“A report was initially drafted to notify Alberta Health that the AER had conducted a screening level assessment of potential risks to human health from wells leaking methane and to provide some preliminary information regarding the wellsites,” reads the statement.

“The report was not finalized due to the different characteristics of each individual well; however, the AER continues to work with Alberta Health, well licensees, and the Orphan Well Association to determine whether the level of methane leaked from these abandoned wells is a risk to health and public safety and what steps should be taken regarding these wells.”

The statement also indicated that the AER has been working with the municipal government on six wells located in Medicine Hat, with the city both monitoring and testing their licensed sites, which are still under investigation.

“Alberta Health’s methane thresholds are indoor values, but the leaks from these wells all vent outdoors, which significantly reduces any risk,” read the statement.

“The wells were referred to AH to ensure we were being as protective of public safety as possible, as AER’s screening found that the wells exceeded Alberta Health’s thresholds.”

CHAT News spoke with one of the co-authors of the draft report, former AER chief environmental scientist Monique Dube. According to Dube, the main issue with the leaks is related back to chronic human health exposure to methane, and it’s associated hydrocarbons.

“Methane can be used as a trigger to assess initial risk with further monitoring and assessment to evaluate the hydrocarbon component where needed,” said Dube, in a written statement.

Dube indicated that parameters on the wells must be compared to health exposure thresholds, and other factors should be considered with risk assessments, such as the proximity to people, and the length of exposure. She also said that there were multiple iterations of the draft report on the wells.

“My role was to oversee analysis of historical and current data sets relative to thresholds provided by Alberta Health who holds the mandate for human health in the province,” said Dube.

“We worked together and recommendations were made to AER executive regarding a more effective and efficient process to assess risk and to work with partners at Alberta Health. I left the organization before the process was developed. I do not know the status of the recommendations.”

Dube said that Alberta Health was very experienced in risk assessments, and indicated that confidence should be placed in their assessment of the data provided by the AER.

“Once these are completed- then any further action or mitigation of the wells falls to the AER mandate,” said Dube.

“Certainly with the legacy of abandoned wells in the province- development of a rigorous process to assess chronic human health exposure risk to those wells that are leaking will be important. The process needs to be based on solid science for monitoring design linked with assessment relative to human health thresholds. A rigorous process will also support and assist industry.”

A statement supplied by Alberta Health indicated that the AER informed the ministry of the abandoned wells in Medicine Hat in October of 2016. The ministry then gave feedback back to the AER about potential health risks in the same month.

“From the review, there were no immediate human health risks identified as the methane was not emitting into a confined space and no indication that the public would be exposed to this concentration as site access is controlled,” read the statement from the ministry.

“Alberta Health’s role in relation to leaking wells is to assess and advise on potential human health hazards and the likelihood of risk to human health. The action that may be taken to physically address issues with leaking wells are the decision and responsibility of the AER. Assessments are on-going by the owner of the well and the AER with input from Alberta Health to select the best options to manage the risks from the emission of methane.”

The statement also indicated that the primary risk to humans from methane is from it’s explosive nature, but that emissions from any source can alter the air quality and environment in which humans reside.

“Methane is also a primary contributor to climate change and Alberta Health will support the efforts of government agencies like the AER to control releases and better protect our environment,” read the statement.

Data on the leakage rates of the local wells is not made public by the municipal government, making it difficult to compare rates over time, beyond the data mentioned in the draft AER report.

“(The) City of Medicine Hat provides testing and monitoring information to the Alberta Energy Regulator (AER) as required under Directive 79, issued in 2014,” read a statement supplied by the city’s communications department.

“Individual results vary significantly depending on distance to the original well, atmospheric conditions and the method of testing. In keeping with AER and industry practice, the City does not publish the results.”

The statement said the city has been monitoring wells in their jurisdiction, as well as those assigned to them.

“Wells are monitored on a regular basis to identify trends and hazards,” read the statement.

“Action plans are developed as required and are implemented once approved by AER.”

UPDATE
The City of Medicine Hat’s communications department contacted CHAT News later Friday afternoon, saying the numbers cited in the initial report do not reflect current testing numbers.

The city says the numbers cited in the AER report came from a single high reading, which likely reflects the fact the methane was trapped for some time. Methane that dissipates into the air is not toxic.

The department also reiterated Medicine Hat remains a safe city and safety is the city’s number-one priority. There are no dangers from known abandoned wells to nearby homes.

The Natural Gas and Petroleum Resources Department works closely with the AER and property owners to manage abandoned wells. The department uses cutting edge methods to test and measure the wells regularly, and the current gathering and venting process is safe.

More information about natural gas safety can be found here: https://www.medicinehat.ca/government/departments/natural-gas-petroleum-resources