Exposure to domestic violence was sufficient to sustain a finding of serious physical harm under Welfare and Institutions Code section 300 subdivision (a). Parents had a history of participating in domestic violence throughout their marriage, including an incident in 2015 where mother stabbed father. Previous peaceful contact restraining orders and mother’s completion of a 52-week domestic violence course had been insufficient to end the domestic violence. The minors were removed from their parents in March 2020, following a police response to a domestic violence call. Mother did not cooperate with the social worker investigation and failed to follow through in getting a restraining order to protect the minors from father. Minor Nathan told social workers that he was present when the most recent domestic violence incident had occurred, and that he had previously witnessed other violent acts between the parents. A joint jurisdictional and dispositional hearing was held and the juvenile court found true section 300(a) and (b) allegations based on the domestic violence between the parents. The court found that removal was necessary to protect the children. Mother appealed, arguing there was insufficient evidence to support the jurisdictional and dispositional orders. The appellate court rejected the argument and affirmed. Section 300(a) creates jurisdiction over a child when there is “a substantial risk that the child will suffer serious physical harm inflicted nonaccidentally upon the child by the child’s parent or guardian.” The application of 300(a) is appropriate when a child suffers, or is at substantial risk of suffering, harm due to the exposure to a parent’s domestic violence. “Domestic violence is nonaccidental.” (In re Giovanni F. (2010) 184 Cal.App.4th 594, 598-599.) Although many cases based on exposure to domestic violence are filed under section 300(b), 300(a) may also apply. Based on the history of domestic violence between the parents and the presence of one or more of the children during the parents’ violent altercations, sufficient evidence existed to sustain 300(a) allegations. Mother’s continued participation in domestic violence despite completing a domestic violence course, her prior failure to comply with court ordered restrictions, and her uncooperativeness with the social worker during the investigation constituted clear and convincing evidence that returning the children to mother’s custody at the time of the disposition hearing posed a risk of substantial danger.