Just looked up SFI's 17.1 spec.
Halon has been outlawed since 1 January 2008, as I read it.
Yrs. truly has been a giant critic of some of SFI's specs, particularly the Dragster/Funny Car, etc. Chassis Specs which are formulated , essentially, by a bunch of old weldors sittin' around a table with their favorite chassis fab suggestions and the destructive testing being after the fact from a serious, sometimes fatal, crash.
BUT, where the spec consists of controlled, scientific, testing, which is the case of almost ALL the other specs. I'm SFI's biggest fan. Those specs have saved a bunch of folk's TOOSHES.