U.S. climate action: Trump is set to rescind EPA endangerment finding.

The Trump administration is expected to rescind the EPA's 2009 endangerment finding that has underpinned U.S. greenhouse-gas rules, and observers say the move is likely to face legal challenges.

The Trump administration is expected to withdraw the Environmental Protection Agency's endangerment finding, the legal opinion adopted in 2009 that has formed the basis for U.S. greenhouse-gas regulation. The finding followed a 2007 U.S. Supreme Court ruling and has guided federal rules for power plants, vehicles and methane controls. President Trump ordered the EPA to review the legality of the finding last year, and officials have moved to rescind it as part of a broader energy policy shift. Observers say the decision is likely to prompt legal challenges and that the Supreme Court's response is uncertain. Current developments: - The EPA endangerment finding has been the legal and scientific basis for U.S. greenhouse-gas regulation since 2009. - The Trump administration has signaled it will rescind the finding after ordering a legal review. - Experts quoted in reporting say rescinding the finding could affect regulations for power plants, vehicle emissions and methane controls. - Legal challenges by states or groups are expected, and the ultimate judicial outcome is undetermined at this time. Summary: Removing the endangerment finding would eliminate a long-standing legal basis for many federal greenhouse-gas rules and could lead to changes in how those rules are applied. Multiple groups and states are reported to be likely to challenge the rescission in court, and the outcome of any litigation remains undetermined at this time.