No compensation may be allowed for any injury or death due to the employee's willful misconduct, including intentional self-inflicted injury, intoxication, illegal use of any schedule I or schedule II drug, or willful failure or refusal to use a safety appliance furnished by the employer, or to perform a duty required by statute. The burden of proof under this section is on the defendant employer.

Source: SL 1917, ch 376 , § 7; RC 1919, § 9442; SL 1921, ch 421 ; SDC 1939, § 64.0202; SL 1991, ch 420 , § 1; SL 2008, ch 278 , § 30.