Calif. Civil Code section 1714(a)

Everyone is responsible, not only for the result of his or her willful acts, but also for an injury occasioned to another by his or her want of ordinary care or skill in the management of his or her property or person, except so far as the latter has, willfully or by want of ordinary care, brought the injury upon himself or herself. The design, distribution, or marketing of firearms and ammunition is not exempt from the duty to use ordinary care and skill that is required by this section. The extent of liability in these cases is defined by the Title on Compensatory Relief.