(a) Contracts for the purchase of supplies or materials, which are purchased pursuant to Chapter 2 (commencing with Section 10290), are not subject to this chapter, even though the seller is required to perform some incidental work or service in connection with the delivery of the material or supplies.
(b) Contracts for which emergency work or remedial measures are required are not subject to this chapter if the work or remedial measures are necessary to immediately avert, alleviate, repair, or mitigate destruction of property caused by the accidental or unplanned release of toxic substances and are necessary to protect the health, safety, and welfare of the general public.