RCW 48.43.093 (1)(a)

(a) A health carrier shall cover emergency services necessary to screen and stabilize a covered person if a prudent layperson acting reasonably would have believed that an emergency medical condition existed. In addition, a health carrier shall not require prior authorization of such services provided prior to the point of stabilization if a prudent layperson acting reasonably would have believed that an emergency medical condition existed. With respect to care obtained from a nonparticipating hospital emergency department, a health carrier shall cover emergency services necessary to screen and stabilize a covered person if a prudent layperson would have reasonably believed that use of a participating hospital emergency department would result in a delay that would worsen the emergency, or if a provision of federal, state, or local law requires the use of a specific provider or facility. In addition, a health carrier shall not require prior authorization of such services provided prior to the point of stabilization if a prudent layperson acting reasonably would have believed that an emergency medical condition existed and that use of a participating hospital emergency department would result in a delay that would worsen the emergency.