Supreme court justice Samuel Alito recused himself on Monday from a major climate-change case after facing calls to step aside due to stock holdings in oil companies.

A letter posted in the case did not specify a reason, but the conservative justice has previously recused himself from other cases involving companies where he holds stock.

“Justice Alito has determined that he will not continue to participate in this case,” the letter reads.

The recusal comes shortly before the court hears the case filed by local officials in Boulder, Colorado, against Suncor Energy and ExxonMobil. It’s one of dozens of similar cases alleging companies deceived the public about how fossil fuels contribute to climate change. Billions of dollars in damages could be at stake.

The high court agreed to hear an appeal from the companies, backed by the Trump administration.

The energy companies argue that the lawsuits pose a serious threat to the industry and that state courts are not the right place to deal with the global issue of climate change.

Alito had so far resisted calls to step aside in the case, which the court agreed to hear in February. He does not own stock in Suncor Energy and ExxonMobil but does have holdings in other oil companies such as ConocoPhillips and Phillips 66, according to his disclosures. The group Consumer Watchdog says that means he could indirectly benefit from a decision in the industry’s favor.

The group’s organizing director, Alexandra Nagy, pointed to the court’s recently adopted code of ethics, which says a justice should step aside if they or their families have a “subject matter or controversy”.

“Justice Alito’s recusal from Suncor v Boulder is the right decision, and one he should have made from the start,” Nagy said in a statement.