Cal. Health & Saf. Code § 12121
Every person who possesses, stores, uses, sells, gives away, delivers, or otherwise disposes of explosives shall keep an accurate journal, record book, or a record of sale in which he shall note each possession, storage, use, sale, delivery, gift, or other disposition of an explosive and the time when such disposition is made whether in the course of business or otherwise. Such journal, record book, or the record of sale shall be kept on file for a period of not less than three years. Field records required to be kept pursuant to Section 12123 need be kept in the appropriate county only for the period of the possession, storage, use, sale, gift, delivery, or other disposition of explosives within that county, after which time the field records may be destroyed.
Ca. Health and Saf. Code § 12121