Washington Supreme Court strikes down Initiative 2066 - right to choose natural gas appliances

Olympia, Wash. — The Washington Supreme Court ruled September 17, 2026, that Initiative 2066 is unconstitutional in its entirety, according to the court’s majority opinion in Climate Solutions v. State of Washington.

The court said the measure violated the state constitution’s single-subject rule and could not be split apart to save only some sections.

I-2066 was approved by voters in the November 2024 general election. The opinion said the initiative affected state and local energy policy in several ways, including protections for natural gas access, limits on local action tied to gas use and changes to building code and decarbonization laws.

The majority said the initiative reached too many separate policy areas at once. The opinion pointed to provisions involving natural gas service, local air quality authority, statewide building codes and repeal of part of the Decarbonization Act. .

“We hold that I-2066 violates the single-subject requirement contained in article II, section 19. Because the provisions that introduce distinct subjects are not severable, I-2066 is unconstitutional in its entirety,” the court said.

The case started after Climate Solutions and several other groups and government entities challenged the initiative in King County Superior Court. That court had already invalidated I-2066 in full. The state, the Building Industry Association of Washington and Ashli Penner appealed directly to the Supreme Court.

The majority said it affirmed the lower court on narrower grounds. Rather than address every constitutional claim raised in the lawsuit, the court said the single-subject issue alone was enough to void the initiative.

“It is impossible to determine which of I-2066’s distinct subjects, if any, the voters would have passed standing on their own merits,” the court said.

A dissent from Justice Mungia said most of the initiative should have remained in place. The dissent argued courts should favor preserving voter-approved laws when possible and said only some sections should have been removed.

“I would hold that I-2066 meets constitutional requirements so long as sections 9, 10, 11, and subsection 12(5) are severed,” Mungia said.

The majority ruling left I-2066 fully invalidated statewide.

In a response to the ruling, the Building Industry Association of Washington and the Washington Hospitality Association said they were disappointed. BIAW Executive Vice President Greg Lane said the decision went against what voters approved in November 2024.

“Today’s decision represents a direct rejection of the clearly expressed will of Washington voters,” said BIAW Executive Vice President Greg Lane. “Nearly two million citizens voted in favor of Initiative 2066 because they believed families and businesses should retain the freedom to choose the energy source that best meets their needs. The Court has now taken that choice away from them. This is government telling the people, ‘Your opinion doesn’t matter.’”

Washington Hospitality Association President and CEO Anthony Anton said; “This decision doesn’t change the underlying challenge our members face: the cost and feasibility of converting commercial kitchens and building systems away from natural gas,” he said. “The Washington Hospitality Association will keep advocating — at the Legislature and, where relevant, at the federal level — for energy policy that gives our members realistic timelines and real choices, rather than mandates that raise costs for operators and, ultimately, guests.”

Groups that challenged the initiative called the ruling a major win for clean air, energy affordability and state climate policy. They said the decision cleared the way for state and local measures tied to building electrification and efficiency to move ahead.

“Today’s ruling is a huge win for Washingtonians who want to secure a healthy, affordable future,” said Caitlin Krenn, Washington Conservation Action Climate and Clean Energy Director. “Initiative 2066 was a deceptive attempt, backed by a megamillionaire, to lock our state into expensive, polluting fossil fuels for decades and undermine the State’s climate policies. By upholding the state’s constitution, the Supreme Court has put us back on track to reap the benefits of cheaper, cleaner renewable energy.”