S.D. Codified Laws § 62-1-1.3
If an employer denies coverage of a claim for any reason under this Title or any reason permissible under Title 58, such injury is presumed to be nonwork related for other insurance purposes, and any other insurer covering bodily injury or disease of the injured employee shall pay according to the policy provisions. If coverage is denied by an insurer without a full explanation of the basis in the insurance policy in relation to the facts or applicable law for denial, the director of the Division of Insurance may determine such denial to be an unfair practice under chapter 58-33. If it is later determined that the injury is compensable under this Title, the employer shall immediately reimburse the parties not liable for all payments made, including interest at the category B rate specified in § 54-3-16.
SDCL 62-1-1.3