Billy Clark v. State of Wyoming, ex rel., Department of Workforce Services, Unemployment Insurance Commission, 378 P.3d 310

Clark was hired as a Homax fuel-truck driver on July 21, 2014; his job required unloading different fuels into correctly labeled tanks.
His supervisor knew Clark had previously mixed fuels at a prior job and warned him at hiring that mixing product could lead to termination; Homax also trained him on unloading procedures.
In August 2014 Clark mixed premium and regular gasoline; he was reprimanded and warned another error would cost his job.
On September 14, 2014 Clark unloaded diesel into the gasoline tank and gasoline into the diesel tank, contaminating ~8,500 gallons (~$25,000); Homax drained the tanks (≈$1,000) and later terminated Clark.
The Department initially awarded benefits, but the hearing officer, the Unemployment Insurance Commission, and the district court denied benefits, finding discharge for misconduct; Clark appealed to the Wyoming Supreme Court.

Issue	Clark's Argument	Homax/Commission's Argument	Held
Whether negligence can constitute "misconduct connected with work" under Wyo. Stat. § 27-3-102(a)(xxiv)	Negligent acts cannot be misconduct; statute requires willful/intentional violation of employer rules	Statute excludes only "ordinary negligence in isolated instances"; serious or repeated negligence may indicate intentional disregard of employer's interests	Negligence of sufficient degree or recurrence can be misconduct; statutory text and precedent so hold
Whether substantial evidence supported the Commission's finding that Clark's mistakes were misconduct	Clark: his errors were unintentional honest mistakes and he lacked incapacity; argued exceptions apply	Commission: prior warning, training, prior similar error, and the severe/recurrent nature of errors show implied intent to disregard employer interests	Substantial evidence supported the Commission: Clark’s repeated, serious errors after warnings amounted to misconduct; benefits denied

Safety Medical Servs., Inc. v. Employment Sec. Comm’n, 724 P.2d 468 (Wyo. 1986) (establishes that negligence of sufficient degree or recurrence can indicate intentional disregard and constitute misconduct)
Doggett v. Wyo. Dep’t of Workforce Servs., Unemployment Ins. Comm’n, 334 P.3d 1231 (Wyo. 2014) (benefits allowed where evidence did not show willful or intentional failure to comply with duties)
Aspen Ridge Law Offices v. Wyo. Dep’t of Employment, Unemployment Ins. Comm’n, 143 P.3d 911 (Wyo. 2006) (reiterates liberal construction for claimants and the need to show misconduct beyond isolated incidents)
SF Phosphates, Ltd. v. Wyo. Dep’t of Employment, Unemployment Ins. Comm’n, 976 P.2d 199 (Wyo. 1999) (analysis of misconduct vs. good-faith errors in employee conduct)
McGraw-Edison Co. v. Dep’t of Industry, Labor & Human Relations, 221 N.W.2d 677 (Wis. 1974) (Boynton rule: recurrence or sufficiently serious single negligent act may imply intent to disregard employer interests)
Simmons v. Commonwealth, Unemployment Comp. Bd. of Rev., 565 A.2d 829 (Pa. Cmwlth. 1989) (comparable facts: repeated negligent mixing of incompatible products, prior discipline, held to be misconduct)