safetymom logo

Phone: 403-214-1558

Fax: 403-253-1806

Certified Health & Safety Consultant Canadian Red Cross Canadian Society of Safety Engineering

The Development and History of H2S Gas Safety in Alberta

In Alberta, the petroleum industry has had  a long and infamous history of  working around hydrogen sulfide gas.  Serious injury, disabilities, knockdowns and fatalities  created a public relations nightmare, motivating the Oil and Gas industry, as a whole,  to set industry standards  for workers  who may be  exposed to hydrogen sulfide  In the early days, a newspaper article publicized that the drilling companies were inviting laborers to enter “the Killing Fields”.
Long gone are the days when there was no legal impact from uncontrolled drilling and production of natural gas, crude oil and petroleum products. that might release H2S.  Workers were untrained, with no safe work procedures, and could be exposed to H2S .  In addition, the public could be exposed during a gas release and blowouts.  Hydrogen sulphide also negatively affected the environment, due to air pollution, from flaring and gas releases during production activities. Uncontrolled blowouts were common, and farmers and nearby towns were exposed to H2S through air pollution, sour spills and hydrogen sulphide entering into underground water wells.
The famous Lodgepole incident in Alberta , where several blowouts knocked down workers and released this poisonous, explosive and corrosive gas into the air, created bad publicity for Oil companies. Over time, pressure was placed on the Petroleum industry to set a standard for safety, to protect their workers, the public and the environment in Western Canada.  Safety organizations, such as Petroleum Industry Training Service, were formed to establish these standards.  After a number of mergers, the organizations changed names, but the program Enform H2S Alive was formulated, to set an entry level training program for workers who could be exposed to this toxic gas with few obvious physical properties.
 This naturally occurring product forms in the province from natural gas reservoirs, hot springs, volcanic gases and crude petroleum.   H2S, also known as stink damp and sewer gas,  can accumulate in sewers, sewage treatment plants or  storage pits in the tanning  and rendering plants. . As a province with large amounts of sulphur
, Hydrogen Sulfide is created naturally by decaying organic matter  which could be  released from  sulphur hot springs, sewage sludge,  and   liquid manure  in farming. ,  It is formed when Sulfur is removed from refining petroleum products and is a by-product of paper in pulp mills.
H2s is often present as a component of untreated intermediate gas and liquid streams that comes from Oil Refineries in the province.
Underground pockets of H2S could be encountered by miners, Well drillers, and workers in tunneling activities. Hydrogen sulphide is also a raw material used  During the manufacturing process.  This could create mercaptans (known as thiols), inorganic sulphides, and  sulphuric acid  that could form H2S.

A common activity in Alberta was to  remove sulphur from petroleum products at oil refineries.  The process units that remove sulphur from the petroleum  are  transported to plants where it is made into sulphuric acids or sulphur.

At oil refineries, Hydrogen Sulfide is produced in process units that remove sulfur from petroleum. It is then transported to a process unit where it is made into Sulfur or Sulfuric acid.
The Enform H2S Alive program  introduces students to the Physical properties of Hydrogen Sulfide.   It  is a colorless, corrosive and very toxic gas with an offensive odor which smells like rotten egg. . It is also highly flammable and can explode when mixed with the correct proportion of air.
 It is a respiratory inhibitor. which affects a persons ability to use their “common sense” or flight/fright response when faced with emergencies. Hydrogen Sulfide’s rotton egg smell  is readily detectable at low concentrations. but , high concentrations can deaden  ones smell by overloading their olfactory senses. When no odor can be perceived, there is no obvious warning to people unless they carry gas monitors to detect its presence.
Its Vapor Density is 1.9, making it slightly heavier than air. But it is typically mixed with other products, such as Methane, that is lighter than air.  When mixed with other gases, it can be released when depressurized.  It may rise with the other materials and stay suspended in air for some time, before settling to low spots… The Enform H2S Alive program notes that workers should be particularly careful around confined spaces where there is no ventilation and the gas can be trapped.
It is soluble in fluids such as produced water, surfactants, gels, inverts, waste materials, sumps and fluid in pits.  Merely by agitating it, depressurizing or heating these materials, H2S can rise and knockdown workers who are in the line of fire.
Hydrogen sulphide gas, at low concentrations, can be slightly irritating to mucous membranes. At higher levels, it can cause pulmonary edema, conjunctivitis of the eyes, and brain damage.
  • Skin contact from liquid forms of H2S can create frostbite, often called “blue skin” .
  • rapid unconsciousness , known as knockdown  can results  from inhalation of the gas. This often leads to falls that can seriously injure the worker.  One reason for educating workers is the observation that other workers in the area panic and run towards the victim to assist them. This often results in a stack of dead workers, making it more difficult to rescue the group.
In Alberta, the 2009 Occupational Health and Safety Act is the legislation to protect workers from chemical exposure.  As of 2009, the 8 hour OEL (Occupational Exposure Limit) is 10 ppm, the Short term exposure is none and the Ceiling is 15 ppm.  Many companies have set higher standards for their safety by aiming for no exposure.  Some employers set their gas monitors to lower limits, such as 5 ppm for the 8 hour day exposure and 10ppm for the ceiling, to have a Standard Operating procedure that is more conservative than the law.
The Occupational Health and Safety Codes have many related sections that apply to H2S.  For example, Part 2 of the Codes notes that employers have to conduct a hazard assessment of the workplace, eliminate or substitute the gas where they can, or control it by engineering, administrative and personal protective equipment strategies.  Engineering out the gas hazard might include lockouts, tagouts, inert, ventilate, blank and blind and other  barriers to H2S.   Administrative controls include implementing training, rules, standards, signage, work permits, use of gas monitors  and procedures that recognize and avoid the gas.  Personal protective equipment to be worn around H2S would be self contained or supplied air breathing apparatus,and wearing flame resistant coveralls  around this toxic and flammable gas.
Given that this gas has few warning properties, it is essential that any worker that could be exposed obtain proper training and the correct resources to protect themselves from this deadly gas.

Leave a Reply

Your email address will not be published. Required fields are marked *