Breaking regulation analysisRegulations, Policy & SafetyNinth Circuit Won’t Rehear Rinnai’s Zero-NOx Challenge. A Rule Covering About 1 Million Units Stays in Force.The Ninth Circuit has declined to rehear the challenge to South Coast AQMD Rule 1146.2, leaving a phased zero-NOx standard in place for covered water heaters, boilers, pool heaters and process heaters across Southern California. The first compliance deadline is already live.TradeVulcan Dispatch Editorial Desk15 min