The Norwegian central bank on Wednesday excluded four Canadian oil and gas companies from its $1-trillion wealth fund, the world’s largest, for producing too much greenhouse gas emissions, its first use of carbon emissions as a criterion to blacklist firms.

Canadian Natural Resources Ltd, Cenovus Energy Inc , Suncor Energy Inc, and Imperial Oil Ltd were excluded from the fund due to "unacceptable greenhouse gas emissions", Norges Bank said in a statement here

The decision was based on recommendations from the Council on Ethics, the fund’s ethics watchdog, because of the companies’ carbon emissions from production of oil to oil sands, the central bank said.

Carbon emissions became a criterion for exclusion from the fund four years ago, and in 2017 the Council on Ethics recommended “a small handful” of firms be blacklisted for producing too much greenhouse gas emissions in either the oil, cement and steel sectors.

Norges Bank also excluded three other companies - Egypt’s ElSewedy Electric Co, Brazilian iron ore miner Vale SA , and Brazilian power holding Eletrobras - for causing severe environmental damage.

Vale declined to comment, while the four Canadian firms did not respond to requests for a comment... ElSewedy could not immediately be reached.