The California Apartment Association’s legal challenge to the South Coast Air Quality Management District’s gas-appliance phaseout is getting national attention.

Three amicus briefs filed Monday urge the 9th U.S. Circuit Court of Appeals to reconsider its July ruling upholding a “zero-NOx” emissions rule that effectively requires a transition to electric appliances in many cases. The briefs came from the American Gas Association; Pacific Legal Foundation and the National Federation of Independent Business Small Business Legal Center, which filed jointly; and the Prime Mover Institute.

CAA is one of the plaintiffs challenging the rule, which will require many housing providers to replace covered gas-fired water heaters, boilers and other equipment with zero-emission alternatives over time.

The outside support matters because the case could reach far beyond the South Coast region. The 9th Circuit’s ruling gives air regulators a potential path to restrict gas appliances through zero-emission standards even after the same court struck down Berkeley’s natural gas ban.

That concern runs through all three briefs.

Pacific Legal Foundation and NFIB argue that South Coast’s rule reaches the same practical result as Berkeley’s ban: covered gas appliances can no longer be used. They warn that governments could otherwise sidestep federal law simply by calling a gas restriction an emissions rule.

The American Gas Association focuses on the court’s reliance on the Clean Air Act, arguing that South Coast’s rule has not been approved by the U.S. Environmental Protection Agency as part of a federally enforceable air-quality plan.

The Prime Mover Institute similarly argues that the Clean Air Act does not require this particular gas-appliance mandate and warns that the ruling could encourage similar restrictions in other jurisdictions.

CAA and its coalition partners have asked the 9th Circuit to rehear the case before a larger panel of judges. The court has not yet decided whether to grant review.

CAA will keep members informed as the case develops.