Alberta’s oil and gas industry is welcoming preliminary findings of a U.S. study that has found no harmful effects in human volunteers exposed to low levels of hydrogen sulphide – the “sour” natural gas developed in the province.
But the industry and an American researcher leading the study – the first of its kind in the world – also caution that its very early findings don’t rule out potential health problems in communities exposed over many years to low levels of sour-gas emissions from gas wells and gas- processing plants.
Hydrogen sulphide, or H2S, is the poisonous sour gas blamed by some landowners – including convicted northern Alberta oilfield saboteur Wiebo Ludwig – for causing health problems in people and livestock.
The Calgary-based Canadian Association of Petroleum Producers (CAPP) contributed $100,000 toward the new study, under way at the Environmental & Occupational Health Sciences Institute in New Jersey.
Most of the funding for the research, which has an initial budget of $1.3 million US, comes from the American Petroleum Institute and the U.S. Environmental Protection Agency.
The study’s preliminary, unpublished findings shouldn’t be interpreted as giving a clean bill of health to everyone in communities located near industrial sour-gas operations, according to a researcher leading the study.
“I don’t think this (study) represents what a community might experience,” Dr. Nancy Fiedler told a Petroleum Technology Alliance Canada (PTAC) forum on air emissions research, held last week in Calgary.
“These are preliminary results, so we do have to look at them with a degree of caution,” added David Pryce, vice-president, Western Canada operations, for CAPP.
“We are certainly encouraged by the results that we’re seeing to date that seem to suggest that low-level exposure to sour gas isn’t having neuro-behavioural impacts,” Pryce said, adding that more research is necessary before anyone can draw definitive conclusions.
The adult volunteers selected for the U.S. study “are the healthiest of the healthy,” with no family history of asthma or other health conditions that might make them more susceptible to low levels of H2S, said Fiedler, associate professor of environmental and community medicine at Robert Wood Johnson Medical School in New Jersey.
In comparison, a more representative population would include people with asthma and other health conditions, as well as toddlers, the elderly and others who are typically more sensitive to any chemical exposure.
Study volunteers also know that they’re going to be exposed to H2S, whereas people in a community “never know when it’s going to happen,” which is likely to affect their reactions, Fiedler told the PTAC conference via a live video-conference presentation.
Despite the U.S. study’s limitations, it is expected to provide some answers to the long-standing question of whether chronic, low-level sour-gas emissions have any adverse health impacts – at least in the majority of the population.
Dr. Sheldon Roth, professor of medicine at the University of Calgary and director of its Environmental Research Centre, said the U.S. study is a good place to start researching the issue.
The study will for the first time establish a baseline of health data for humans exposed to carefully controlled low levels of H2S, Roth said in an interview. “It’s a very solid study given what we have and the fact that it’s healthy volunteers, but it shows that we can do studies on humans at low levels.”
But Roth and some other Alberta medical researchers and physicians also say it is past time for the province to undertake its own multi- million-dollar, long-term study of individuals and communities exposed to sour-gas emissions.
“It’s well overdue,” Roth told the PTAC forum. “I think what we need to be is more proactive.”
Roth and U of C colleague Verona Goodwin recently completed a review of scientific literature and other information on the issue for Alberta Environment.
Their report, released last month, said that: “There are many examples that hydrogen sulphide should be regarded as a broad-spectrum toxicant and that repeated exposure may result in cumulative effects on many organ systems such as brain, lung and heart.”
Last year, Alberta Health and Wellness decided to put on hold a human health study, which had originally been proposed as part of a major human and animal health study in Western Canada, until results of the animal research component are known.
But Dr. David Swann, a public health physician and former provincial medical officer of health, said that in addition to the animal research, the Alberta government should fund a long-term study on the chronic health effects of prolonged, low-level exposure to sour-gas emissions.
“Alberta could be a leader in this area,” he told the PTAC forum.
The Alberta government has contributed the biggest chunk of funding – $11 million – to the continuing $17-million, five-year study on the health effects of sour-gas emissions on beef cattle. “I think we need to make a similar commitment in the human health (area),” Swann said.
Fiedler said that U.S. researchers have so far exposed 10 volunteers to concentrations of 0.05, 0.5, and five parts per million H2S, for about two hours at a time.
In comparison, Alberta occupational regulations permit oil and gas workers to be exposed to up to 10 ppm of H2S for eight hours at a time.
Each subject in the U.S. study is exposed to the sour gas while sitting inside a sealed chamber in which the gas concentration, temperature, humidity and ventilation rate are all carefully controlled.
The study is the first ever to measure people’s reported symptoms, sensory function and cognitive performance as they’re being exposed to carefully controlled, low levels of H2S.
Researchers have found that subjects report more symptoms, including throat, nose and eye irritation, chest tightness and feelings of anxiety, at the highest H2S concentration of five parts per million.
However, there’s no indication so far that these self-reported symptoms have any detectable adverse effects, Fiedler said.
Being exposed to the H2S produces no significant differences in the volunteers’ ability to perform computer tests, in their reaction time and ability to learn tasks when given spoken instructions, in their visual perception and in their balance.
The researchers want to study at least 100 volunteers before drawing any conclusions about these levels of sour-gas exposure in healthy subjects, Fiedler said.
The PTAC forum also included an update on the $17-million Western Canada animal health study, which is investigating sour-gas emissions and health effects in cattle and in a wild bird species.
Michael O’Connell, study manager for the Western Interprovincial Scientific Studies Association, an independent group overseeing the research, said the findings will be made public in the summer of 2005 – a year later than planned because of the enormous amount of data collected and which still has to be analysed.
“There are lots of perceptions out there about what’s going on between cattle and oil- and gasfield facilities,” O’Connell said.
“And (our study) is going to have the data that hopefully will definitively say this is what’s going on or not going on.”
Researchers have completed 18 months of collecting information in the field, including detailed records on about 33,000 beef cattle in a total of 200 herds in Alberta, B.C. and Saskatchewan.
The research team collected data on the cattle’s productivity, health and immune system function, analyses of water the animals drank and their feed, as well as continuous air monitoring data from pastures they used.
To look at effects of sour gas emissions on a wildlife species, the team also gathered information on the health of 500 European starling nestlings in about 130 nests.
The research team has struggled since the study began in 2001 to find the $17 million needed to complete the research, although all of this funding has now been secured, O’Connell said.
Some of the money is in the form of repayable grants, however, so researchers are still looking for more government and industry partners to contribute funding.
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