Canadian Occupational Safety

August/September 2015 19 shortness of breath, wheezing, chest tightness and permanent lung damage. Long-term exposure to H2S has been reported to cause low blood pressure, headache, nausea, loss of appetite, eye infl ammation and chronic cough. "Sustained exposure to H2S can affect the lung function over the longer haul, it can affect the respiratory system in general and the cardiovascular system or blood supply system," says MacGillivray. ENGINEERING CONTROLS Every employer in the oil and gas industry must conduct a hazard assessment with worker input to determine where workers are most likely to be exposed to H2S, and then consider the different controls that need to be put in place. They should consider engineering controls to remove the substance or create a barrier between the worker and the toxic gas, such as ventilation and closed systems that vent to a fl are, according to WorkSafeBC. Fortunately, there are a lot of engineering controls in the design of drilling operations that minimize the chance of H2S being released at the surface, such as the types of drilling fl uids used, well control, blow out preventers, annular bags, well service equipment and piping. Treatment methods are also used to remove H2S from liquid gas streams. For example, ammonia is a "scrubber" gas that is used to knock out H2S from the gas stream, says David Chalmers, president and general manager of Trinity Safety & Training in Saskatoon. "We would put on, say, a 400 barrel tank that can have H2S in the tank, but in order for it to not come out of the vent and expose workers, it needs to go through the ammonia tank to knock out the H2S." MONITORING SYSTEMS While H2S has a strong smell of rotten eggs, workers should never rely on their noses as reliable monitors for the gas. Humans have a wide range of sensory abilities so some people may not be able to smell it at all, while others can still smell it at fairly high amounts, says Levine. In general, the sense of smell is blocked at 150 ppm. "Once you smell it, it's in your blood stream so it's sort of like tasting a poison food to see if it's safe," she says. "Once it gets into your system, we have a poor sensory threshold for sulphur and it shuts off your ability to smell it… and so you think it's gone away, but that is a bad idea because it's probably increasing." If workers are able to smell the gas, they should get out of the area immediately. One type of gas monitoring pre- dominant throughout the oil and gas industry is electronic personal devices. These are worn by the worker and may just monitor for H2S, but often they have multiple heads to monitor carbon monoxide, oxygen defi ciency or explo- sive atmospheres. Portable monitors are also available that can be carried to the work site and moved with workers. If the alarm goes off, it would alert all the workers in the immediate area that there is a threat. There can also be a fi xed monitoring system throughout the plant that would send site-wide warning systems if H2S over a certain level is detected. These are often found in gas plants, separator buildings, process buildings and compressor buildings. They can shut down the area from a distance, pull out gas and pump air in and call emergency services to go to the site. In the past, gas detector tubes were used but these have gone by the wayside as they do not provide real- time gas monitoring. EMPLOYEE EDUCATION Training workers on H2S is crucial. The industry standard for all workers in the fi eld is Enform's H2S Alive course. More than 170,000 workers took the course in 2014 alone. "Anyone who has the chance of exposure to H2S in the industry should be taking this course and, by in large, that covers just about everybody. The industry really has adopted it. The universal approach to it is this is a standard course you need to take if you're going to be in the industry," says MacGillivray. "Even if the job is not today being exposed to it, tomorrow you might be in a slightly different job or encounter a situation where H2S exists." The full-day training course covers the physical properties of H2S, where workers may encounter it, health hazards and what concentrations may become a risk. Workers learn how to protect themselves as well as how to perform a rescue. They learn how to use and properly don a self-contained breathing apparatus. Workers are required to recertify every three years. "What we have an issue with is new workers that don't understand H2S and until they see (how dangerous it is) they don't believe it, and then we have complacent workers with many years in the industry and they tend to get too overconfi dent," says Levine. Employers should provide workers with written safe work procedures. It's also important for employers to clearly label all piping and valves that carry H2S, and wherever an H2S buildup or leak is possible, warning signs must be posted. PROTECTIVE EQUIPMENT H2S has a very wide range of fl am- mability — the lower explosive limit is 4.3 per cent and the upper is 46 per cent — so workers are required to wear fl ame retardant coveralls. In areas of high H2S levels or where an leak has occurred, workers must wear approved respiratory protection. A positive-pressure supplied-air breathing apparatus (SABA) is required for work areas where H2S exceeds the eight-hour OEL or the ceiling limit. This respirator would be mostly used for work-related purposes, such as inside confi ned spaces, vessels or tanks. A positive-pressure, self-contained breathing apparatus (SCBA) would mostly be used for doing rescues and independent work for exposures at or above 100 ppm. "(H2S Alive) provides very basic training but the expectation is that the company tops up that training. (Train- ing providers) kind of show them which end is up — they're certainly not going to be profi cient operating that equipment until they get onto a job site," says Chalmers. "We do see com- panies doing more and more drills; that is far more frequent now than it was 15 years ago." In Saskatchewan, workers are required to receive training every six months on how to operate a breathing apparatus if they are required to wear it in an emergency application — a standard that should be adopted in other provinces as well, says Chalmers. Employers should provide workers with a written emergency response procedure. If a person has been exposed to H2S and is down, a rescue operation will need to be performed and there are seven main steps for a response plan workers should follow, from evacuation to medial aid (see sidebar). A key part of a responder's assess- ment is to determine if a rescue can in fact be completed. Sometimes per- forming a rescue is too high risk. To determine if it is safe, rescuers should examine the levels of H2S that their monitors are showing and assess the situation, including how many people are down and how many are available to rescue. "Very often when we have an inci- dent like this, people are so keen to get in and help people that they inad- vertently put themselves at risk by not taking time to don their own equip- ment, assess the situation and move people away from the risk," says Mac- Gillivray. "Sometimes, with the best intentions, a followup individual has put themselves in a bad situation." Congratulations to the following OHS professionals who have recently been granted the Canadian Registered Safety Professional (CRSP) ® Professionnel en sécurité agréé du Canada (PSAC) ® designation. The BCRSP is a self-regulating, self-governing organization accredited by the Standards Council of Canada to ISO 17024 (Personnel Certification Body) and by BSI Management Systems to ISO 9001(Quality Management System). Board of Canadian Registered Safety Professionals/Conseil canadien des professionnels en sécurité agréés 6700 Century Avenue, Suite 100, Mississauga, ON L5N 6A4 905-567-7198, 1-888-279-2777, www.bcrsp.ca Anthony Allenbrand CRSP Robert Aloisio CRSP Peggy Bakken CRSP Christopher Banbury CRSP Ali Bayati CRSP Gregory Beck CRSP David Berry CRSP Tyler Blanchet CRSP Shauna Bochon CRSP Kenneth Brodie CRSP Larissa Brown CRSP Jason Burnett CRSP Mylene Busilan CRSP Shawn Bymoen CRSP David Phillip Campbell CRSP Sergio Carvana CRSP Eric Cheng CRSP Cory Cherniwchan CRSP Juliana Chu CRSP David Clark CRSP Heather Clarke CRSP Carolyn Cuthbertson CRSP Michael Desotti CRSP Sylvie Dionne CRSP Ryan Elgert CRSP Stephanie L. Fitchett CRSP Peter Frigon CRSP Henry Grbac CRSP Tim Greenacre CRSP Hayden Greenshields CRSP Martin Grund CRSP Ralph Gubler CRSP Stephen Henchel CRSP Howard Hickman CRSP Zaya Janou CRSP Ewa Kaczmarczyk CRSP Jeremy Kelly CRSP Adrian Khan CRSP Sila Kosegi CRSP Yoon (Kelly) Kwon CRSP Carrie Lalonde CRSP Shirley Lalonde CRSP Holly Lam CRSP Mathieu Langelier CRSP Cheryl L'Arrivee CRSP Mike Lemay CRSP Randolph LeRoy CRSP Pierre Marentette CRSP Barry Martin CRSP Endurance Maya CRSP Todd McCabe CRSP Craig McGrath CRSP Shawn McWilliam CRSP Scott Melville CRSP Andrew Mendoza CRSP Melissa Morden CRSP Tanya Morose CRSP Waleed Mostafa CRSP Steven Mueller CRSP David Murphy CRSP Patrick Ndjom CRSP David Nguyen CRSP Paul O'Connor CRSP Tim O'Quinn CRSP Wade Osmond CRSP Tianyou Pan CRSP Ilinca Papaz CRSP Daryl Pont CRSP Laura Prevett CRSP Brant Prunkl CRSP Stephanie Raill CRSP Ana Reyes CRSP Mallory Roberts CRSP Chad Sales CRSP Diane Samoleski CRSP Sylvia Senoran CRSP Shanroy Shirley CRSP Patrick Sontrop CRSP Daniela Stamu CRSP Anthony David Toews CRSP Ruth Uy CRSP Caitlin White CRSP Aaron Wildgrove CRSP James Williams CRSP Charyl Anne Wilson CRSP Gordon Yee CRSP Viorica Zugravu CRSP Scott Zwack CRSP Board of Canadian Registered Safety Professionals

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