California Code, Health and Safety Code - HSC § 117775

(a) “Transfer station” means an offsite location permitted by the department where medical waste is loaded, unloaded, stored, or consolidated by a registered hazardous waste hauler during the normal course of transportation of the medical waste.

(b) “Transfer station” does not include any onsite facility, including, but not limited to, common storage facilities, facilities of medical waste generators employed for the purpose of consolidation, or onsite treatment facilities.