H2S--also known as sour gas, sewer gas, and stink damp--is a highly toxic gas that appears naturally in the earth in petroleum and natural gas. Although it does not strike often, when it does, it is deadly. Too much can kill a worker in a few seconds.
H2S exposure can happen to oil and gas workers during the drilling and production of natural gas, crude oil and petroleum products. You can also find it in refineries, oil and gas wells, battery stations and pipelines. Truck drivers are also at risk if they are transporting fluids containing a solution of H2S as they have some of the highest fatality rates for H2S.
Like most health and safety concerns,deaths are preventable. Here are the top 4 tips to prevent deaths by H2S:
The eight-hour occupational exposure limit (OEL) for H2S in Alberta is 10 parts per million (ppm) and the top limit is 15 ppm. At only 20 ppm, exposure to H2S can cause eye, nose, throat and lung irritation, digestive upset and loss of appetite. Hs2 levels of 100 ppm and more are immediately hazardous to life and health. This level is much lower than most other toxic gases. Exposure of 200 ppm can create extensive irritation of the nose, throat and lungs, along with headaches, nausea, vomiting and dizziness. Pulmonary edema (fluid in the lungs) can also occur.Above 500 ppm, employees may experience sudden collapse (knockdown), unconsciousness and death. H2S is a nerve gas: that’s what’s unusual about it. It affects how easily your central nervous system and your body is able to use oxygen, and that’s what can lead to a quick death.
- Engineering Controls
Employers in the oil and gas industry are required to conduct a hazard assessment to find where workers are most likely to be exposed to H2S. Afterwards, they can put in place different controls to prevent exposure. The best controls are physical barriers like ventilation and closed systems that vent to a flare, according to WorkSafeBC. Luckily, there are many engineering controls in the design of drilling operations that limit the chance of releasing H2S to the surface, such as the types of drilling fluids used, well control, blowout preventers, annular bags, well service equipment and piping.
- Monitoring Systems
Although H2S smells like rotten eggs, employees should never rely only on their noses to check for the gas. If you are able to smell H2S it may be too late. Once you smell it, it is in your blood stream. Smelling H2S is like tasting poisoned food to see if it’s safe. When H2S levels get higher than 150 ppm, your sense of smell is blocked completely. Now most of the oil and gas industry uses electronic personal devices for gas monitoring. These are worn by the worker and can monitor for H2S, as well as carbon monoxide, oxygen deficiency or explosive atmospheres. Other options are portable monitors that can be carried to the work site and fixed monitoring systems that can be installed throughout a plant.
- Employee Education
Is your Alive ticket out of date? You can take H2S training in our in-house, state-of-the-art training facility at Matrix Labour Leasing. Although few accidents happen every year, each time they happen they can be deadly.
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