The standards, however, shall not supersede any rule or regulation of any district governing permanent sandblasting operations or equipment, which rule or regulation was in effect on January 1, 1974.
For purposes of this section, “permanent sandblasting operations or equipment” means sandblasting operations conducted, or sandblasting equipment located, in a building which is used, in whole or in part, for sandblasting operations.
(Added by Stats. 1975, Ch. 957.)