Failed smog test fuel tank not holding vacum

Since when does SoCal require smog for a 76? When I lived there my 65 required smog just once when you sold it, and the limits were fairly loose. Did they require you install a catalytic converter or did 76 CA cars come that way? I doubt it since I don't recall even hearing of cat converters until ~1979 when some new Corvettes started grass fires.