Ontario Regulation 311/25 establishes operational, geographic, and procedural rules to support the implementation of the Geologic Carbon Storage Act, 2025. This act provides the framework for authorizing, regulating, and overseeing carbon dioxide storage projects in Ontario. The regulation establishes key definitions, including the role of a “unit area operator,” who is responsible for managing all phases of a carbon storage site, from construction and operation to decommissioning and land remediation.

The regulation sets clear geographic limits on where carbon storage sites may be located. While sites may generally be situated anywhere in Ontario, they are expressly prohibited within the St. Clair River, the Detroit River, Lake Ontario, and within 100 metres of the international boundary with the United States. Permits for research, evaluation, or storage may only be issued if proposed sites are at least 100 metres from the water’s edge of these boundary waters, reflecting a precautionary approach to transboundary and aquatic risk.

Further technical restrictions apply to storage permits. Eligible storage repositories are limited to saline aquifers or depleted oil and gas reservoirs within Paleozoic sedimentary rock formations, and carbon dioxide injection must occur at depths of no less than 800 metres below ground surface. Storage sites must also be located on lands specifically identified in a schedule to the regulation, ensuring that only pre-approved areas are eligible for long-term storage activities.

The regulation prescribes minimum project scale thresholds by requiring at least 15 million tonnes of carbon dioxide and participation by at least one industrial emitter. It clarifies that this threshold may include carbon dioxide captured through direct air capture facilities, enabling flexibility in how storage volumes are achieved.

A significant portion of the regulation addresses decision-making criteria for the Minister and the Ontario Land Tribunal. When issuing, amending, renewing, transferring, or closing authorizations, decision-makers must assess whether proponents can meet their legal obligations and operate without posing unacceptable risks to public safety, the environment, or other land and resource uses. These same considerations guide the imposition of conditions on authorizations and apply to Tribunal decisions where applications are referred.

Detailed rules govern unitization orders, which consolidate pore space rights across multiple landowners for efficient storage development. Consent is deemed sufficient when landowners representing at least 70 percent of the projected pore space volume agree. Additional prerequisites include ministerial consent for public pore space, surface rights access, project readiness, and a reasonable expectation that required storage permits will be obtained.

Ontario (311/2025) December 30, 2025
Disclaimer: Insights are for informational purposes only and does not reflect RRI’s official position or constitute legal opinion.