“Nonconforming junkyard” means either of the following:
(a) A junkyard lawfully in existence on October 6, 1966, but which does not conform to the requirements of this article.
(b) A junkyard which is lawfully in existence at any time but later fails to comply with the requirements of this article due to special conditions as defined in subdivision (f) of Section 746.
(Added by Stats. 1977, Ch. 919.)