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January 27, 2010
Controversy follows sour gas around Alberta and B.C.
EDMONTON – Sour gas flared back into the news this month with the arrest and release of activist Wiebo Ludwig. The northwestern Alberta man, who blames sour gas development near his farm for the death of his cattle and even one member of his family, was convicted for his role in bombing oilpatch facilities in the 1990s. Police recently searched his property in connection with similar bombings just over the provincial boundary in British Columbia, although he maintains he wasn't involved.
He's not the only person who maintains such developments are poisoning the land and life upon it.
Controversy follows this industry around. Development of any significant sour gas deposit is generally followed by a major public outcry. Communities that have been affected in the last decade or so include Sundre in western Alberta, Drayton Valley southwest of Edmonton and the Beaverlodge area near Ludwig's home. Companies have applied to drill for sour gas even on the outskirts of Calgary.
In an attempt to clarify the issues, The Canadian Press has explored some of the most commonly asked questions about sour gas.
Q: What is it?
A: Sour gas is a term applied to any natural gas that contains a measurable amount of hydrogen sulphide, or H2S. Such concentrations can vary from barely detectable to more than 10 per cent. It is sometimes referred to as "rotten-egg gas" because it is marked by a strong smell even at very low levels. Sour gas is heavier than air and tends to collect in low-lying areas. It is also corrosive and requires special handling in pipelines and processing facilities, where the sulphur is stripped out to turn it into "sweet" gas.
Q: How common is it?
A: Quite. About 30 per cent of Alberta's natural gas production is from sour gas, and deposits are found in many areas throughout the province and into British Columbia. Alberta has 6,000 sour gas wells, 240 processing plants and 12,500 kilometres of sour gas pipelines.
Q: How dangerous is it?
A: Very. In March 2008, an oilpatch worker died while changing a meter at a sour gas facility in northwestern Alberta. He was working alone and wasn't discovered until a co-worker was sent to check on him. Headaches and nausea can result from minute concentrations as low as one part per million, lung function begins to deteriorate at about 100 parts per million, and death occurs within minutes at 750 parts per million.
Q: How common are large leaks?
A: They're comparatively rare. Alberta's energy regulator reports 16 temporary shutdowns of gas facilities in 2008. Most were due to H2S emissions. The same agency averages 300 complaints a year about odours, although those smells are often found to be unrelated to energy development. No sour gas wells suffered blowouts – catastrophic, sudden releases of gas – in 2008 and there were 25 low-level releases from small leaks in pipelines. No one outside the industry has ever been killed in Alberta by sour gas.
Q: What about long-term exposure?
A: Activists complain that periodic exposure over months and years may not show effects immediately, but they can create a variety of long-term health problems for humans and livestock. Such exposure comes from occasional leaks from pipelines, other facilities or from flaring, a standard oilpatch practice in which excess gas is piped up a stack and burned. The flares look like giant matchsticks on the prairie. The process converts H2S to sulphur dioxide, an even more toxic chemical which can start to affect people with respiratory conditions at levels as low as 0.25 parts per million. As well, H2S often doesn't burn completely in a flare stack and so minute amounts are vented directly into the atmosphere.
Q: What does the science say?
A: Here is where it gets murky. Long-term studies on the health effects of sour gas facilities are difficult and rare. Most research has focused on cattle. A 1998 University of Guelph study found no widespread impacts on cattle near sour gas facilities but could not rule out localized effects. In 1999, a three-year University of Saskatchewan study suggested that long-term exposure for cattle was associated with higher rates of spontaneous abortion, stillbirth and non-pregnancy, but the difficulty in getting reliable data left many questions. The most recent study, a 2006 paper from the Western Interprovincial Scientific Studies Association, found no association between low-level exposure and animal health – with one exception. Calf death rates increased slightly, as did the number of times the animals required veterinary care, with exposure to both H2S and SO2. None of the studies was definitive and the conclusions were valid only for large herds. Still, many ranchers are convinced that sour gas wells or facilities on or near their land hurt their herds and possibly their families.
Q: What are government and industry doing?
A: Companies are required to file emergency response plans with their well applications, including an evacuation plan – although some people complain the evacuation radius is too narrow. As well, industry has significantly reduced flaring from both well sites and processing facilities in recent years, although older facilities are grandfathered from modern regulations.
© 2009 The Canadian Press
