California Code, Labor Code - LAB § 1720.3

(a) For the limited purposes of Article 2 (commencing with Section 1770), with respect to contracts involving any state agency, including the California State University and the University of California, or any political subdivision of the state, “public works” also means both of the following:

(b) For purposes of this section, the “hauling of refuse” includes, but is not limited to, hauling soil, sand, gravel, rocks, concrete, asphalt, excavation materials, and construction debris. The “hauling of refuse” shall not include the hauling of recyclable metals such as copper, steel, and aluminum that have been separated from other materials at the jobsite prior to transportation and that are to be sold at fair market value to a bona fide purchaser.