Hydrogen sulfide and your health

Learn about hydrogen sulfide, its health risks and how to reduce your exposure.

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About hydrogen sulfide

Hydrogen sulfide is a colourless gas that has a characteristic rotten egg smell. It's commonly found in soil, air and water.

It can be produced as part of normal body functions, or when plants and animals die and decompose. The gas is part of the natural sulfur cycle and has many natural sources, including:

It can also be released from industrial activities, such as:

Hydrogen sulfide can also be released from inactive oil and gas wells as a result of former activity.

Safety of hydrogen sulfide

At high levels of exposure, hydrogen sulfide can damage your nervous system or other organs and tissues in your body.

Under Canada's Chemicals Management Plan, we review and manage the potential risks that chemical substances can pose to people in Canada and the environment. The first stage of the review process is a draft chemical risk assessment.

In 2017, we published a draft assessment of hydrogen sulfide.

Since then, we have become aware of new information about the incidental releases of hydrogen sulfide from inactive oil and gas wells, and potential harms to human health and the environment. As a result, we have updated the draft assessment.

We've completed the updated draft assessment. We're proposing that hydrogen sulfide may pose a risk to your health when it's released at high levels from inactive oil and gas wells. We're also proposing that these releases are harmful to the environment.

Our updated draft assessment found that exposures to hydrogen sulfide from other sources aren't high enough to pose a risk to human health.

What we're doing to reduce your exposure to hydrogen sulfide

Our assessment is not yet final. We're continuing to evaluate the potential risk posed by hydrogen sulfide before we publish our final conclusion. This includes:

All provinces, and several territories, have requirements in place for oil and gas well management. We will review current regulatory actions and programs across jurisdictions that may reduce incidental releases of hydrogen sulfide from inactive oil and gas wells. This will inform potential actions that can reduce the exposure of people in Canada and the environment to these releases.

If the proposed findings for hydrogen sulfide are confirmed in the final assessment, we will consider:

What you can do to reduce your exposure to hydrogen sulfide

You can provide any comments on our draft assessment during the 60-day public comment period.

If you have concerns about exposure to hydrogen sulfide, contact your provincial or territorial government about potential oil and gas well locations in your area.

If you have concerns about having been exposed to hydrogen sulfide, talk to a health care provider.

If you're exposed to hydrogen sulfide at work, talk to your employer and occupational health and safety (OHS) official about:

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