California Code, Vehicle Code - VEH § 32052

(a) The notification required by Section 32050 shall reach the department at least 72 hours before the beginning of the 48-hour period during which departure of the shipment of any material designated in Section 32050 is estimated to occur, and the department shall notify the sheriffs and the police chiefs as specified in subdivision (a) of Section 32050 at least 36 hours before the beginning of the 48-hour departure period specified in subdivision (a) of Section 32051, who shall notify the fire chiefs, as provided in Section 32050. A copy of the notification shall be retained by the department for three years.

(b) The carrier shall also notify, by telephone or telegram, the department if there are any changes in the scheduling of a shipment, in the routes to be used for shipment, or any cancellation of a shipment. The department shall, in turn, notify the sheriffs and the police chiefs specified in subdivision (a) of Section 32050 that would be affected by these changes in the scheduling of a shipment, in the routes to be used for a shipment, or the cancellation of a shipment, who shall notify the fire chiefs, as provided in Section 32050. The department shall maintain for three years a record of each telegram and telephonic notification.