The latest auction in Quebec and California's joint cap-and-trade market has sold out.
The sell-out is the second such auction in a row for the market, which Ontario plans to join next year.
The Quebec-California market has seen an average of three-quarters of available credits sell at auction since 2014.
The system aimed at lowering greenhouse gas emissions puts caps on the amount of pollution companies in certain industries can emit.
If they exceed those limits, they must buy an equal number of allowances at auction or from other companies that come in under their limits.
Ontario started its own cap-and-trade program this year and has sold out its first two auctions, bringing in revenue of nearly $1 billion. It will hold its next solo auction on Sept. 6.