If you smell Hydrogen Sulfide (H2s) near your home or suspect a leaking gas well, phone 911 or contact the Spills Action Centre at 416-325-3000 or toll free at 1-800-268-6060.
If you suspect you have an abandoned gas well on your property, visit the Oil, Gas and Salt Resources Library website and search for the well on your property.
What is Hydrogen Sulfide?
Hydrogen Sulfide is a colourless gas that smells like rotten eggs. It is flammable at very high concentrations and can be lethal. It is a risk around abandoned gas and water wells. It forms naturally in the environment and can also be associated with animal farms, industrial plants, sewers and wastewater treatment plants.
How can I be exposed to Hydrogen Sulfide?
You are most likely to inhale H2S when you are near a source, like an abandoned well. Hydrogen Sulfide usually break down in the air and exposure is only likely to occur if there is an ongoing source. The general population will have likely had exposure to H2S at some point.
Gas wells that are not properly maintained or decommissioned may release H2S. Sometimes, well-drawn water will contain H2S.
Exposures by ingesting food or drink or by absorption through direct contact with skin can occur though it is unlikely. H2S does not accumulate in the body. It is rapidly metabolized in the liver and excreted in the urine.
How is Hydrogen Sulfide detected?
People usually smell Hydrogen Sulfide even at very low concentrations in the air, ranging from 0.0005 to 0.3 parts per million (ppm). These levels in the air are not dangerous and will not cause negative health effects. It should be noted that there is no way to tell by smell alone if you are detecting low or high concentrations of Hydrogen Sulfide; in fact, concentrations around 100ppm will temporarily hinder your ability to smell the gas. You cannot rely on your nose to tell you how much Hydrogen Sulfide gas is present.
What are the health effects of Hydrogen Sulfide?
Exposure to low concentrations (10-100 ppm) of Hydrogen Sulfide may cause:
- Irritation to the eyes, nose, or throat
- Difficulty in breathing for some people with asthma
- Headaches
- Poor memory
- Tiredness
- Balance problems
Brief exposures to high concentrations of Hydrogen Sulfide (greater than 500 ppm) can cause a loss of consciousness. In most cases, the person will likely regain consciousness without any other effects. However, in some people, there may be permanent or long-term effects such as headaches, poor attention span, poor memory, and poor motor function. In very high concentrations, death is possible due to respiratory paralysis.
Abandoned Gas Wells
Companies and landowners have drilled thousands of wells across Ontario to extract oil and gas. When wells are deactivated, they must be permanently sealed in a process known as abandonment. Not all abandoned wells have been properly decommissioned and even those that have been plugged can still leak and pose a hazard.
Review provincial map shown the location of known wells!
How do I find a gas or oil well on my property?
Gas and oil wells could have been constructed almost anywhere but are usually in farm fields or forests. The first step in determining if there is a gas or oil well on your property (abandoned or otherwise) is to search for it on maps or in other resources available on-line or elsewhere. Speaking with long-standing neighbours or well drillers in the area may also shed light on where these wells are (local knowledge). Finally, a systematic approach of walking the land may produce evidence of an abandoned well.
The provincial government has more information on finding abandoned gas and oil wells.
Gas Well Resources and Contacts
The Abandoned Works Program through the Ministry of Natural Resources helps Ontarians plugs wells on their property. Landowners with gas wells can contact the Ministry to determine if they qualify for the program. For more information, contact: https://www.ontario.ca/page/abandoned-works-program
If you suspect you have an abandoned gas well on your property, visit the Oil, Gas and Salt Resources Library website and search for the well on your property.
For more information contact:
Petroleum Operations Section
Ministry of Natural Resources and Forestry
posrecords@ontario.ca
519-873-4634
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