James B. Kelly, Relator, vs. REO Plastics, Inc., Respondent, Commissioner of Economic Security, Respondent.

may not be cited except as provided by

Minn. Stat. § 480 A. 08, subd. 3 (1998).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C2-98-1170

James B. Kelly,

Relator,

vs.

REO Plastics, Inc.,

Respondent,

Commissioner of Economic Security,

Respondent.

 Filed April 13, 1999

 Affirmed

 Willis, Judge

Department of Economic Security

File No. 1280UC98

James B. Kelly, 624 3rd Avenue NE, Osseo, MN 55369 (pro se relator)

REO Plastics, Inc., 11850 93rd Avenue North, Maple Grove, MN 55369 (respondent)

Kent E. Todd, Minnesota Department of Economic Security, 390 North Robert Street, St. Paul, MN 55101 (for respondent Commissioner)

Considered and decided by Lansing, Presiding Judge, Schumacher, Judge, and Willis, Judge.

 U N P U B L I S H E D O P I N I O N

 WILLIS, Judge

Relator James B. Kelly challenges the decision of respondent Commissioner of Economic Security that he is disqualified from receiving reemployment insurance benefits because of misconduct. We affirm.

 FACTS

On January 13, 1998, respondent REO Plastics, Inc., discharged Kelly because of a physical confrontation with another employee. Kelly applied for reemployment insurance benefits. An adjudicator from the Department of Economic Security determined that Kelly was not disqualified from receiving benefits, and a reemployment insurance judge affirmed that determination. REO appealed to the Commissioner of Economic Security.

The commissioner's representative reversed the reemployment insurance judge's decision, concluding that Kelly is disqualified from receiving reemployment insurance benefits because of misconduct. The commissioner's representative issued an amended decision requiring Kelly to repay all benefits received. This certiorari appeal followed.

 D E C I S I O N

Kelly claims that the commissioner's representative erred in concluding that he is disqualified from receiving reemployment insurance benefits, arguing that the decision is unsupported by substantial evidence, is arbitrary and capricious, and violates the Minnesota Constitution.

An employee "discharged because of misconduct that interfered with and adversely affected that employment" is disqualified from receiving reemployment benefits. Minn. Stat. § 268.095, subd. 4(1) (1998). But see Smith v. Employers' Overload Co., 314 N.W.2d 220, 222 (Minn. 1981) (requiring courts to construe narrowly statute's disqualification provisions). Misconduct is defined as

intentional conduct showing a disregard of:

(1) the employer's interest;
(2) the standards of behavior that an employer has the right to expect of the employee; or
(3) the employee's duties and obligations to the employer.

Minn. Stat. § 268.095, subd. 6 (1998). An employer must prove, "by the greater weight of the evidence, that an employee has committed `misconduct.'" Soussi v. Blue & White Serv. Corp., 498 N.W.2d 316, 318 (Minn. App. 1993).

The commissioner's representative concluded that REO discharged Kelly "for reasons amounting to misconduct." On appeal, this court views factual findings in "the light most favorable to the decision below, and we will not disturb those findings if there is evidence reasonably tending to support them." Hein v. Gresen Div., 552 N.W.2d 41, 43 (Minn. App. 1996) (citation omitted). But whether the findings support a determination of misconduct is a question of law, subject to de novo review. Cook v. Playworks, 541 N.W.2d 366, 368 (Minn. App. 1996).

The commissioner's representative found that: (1) Kelly pushed a temporary employee when the aisle leading to the time clock was blocked; (2) the temporary employee asked Kelly why he did not say "excuse me"; (3) Kelly responded by stating, "[D]o you want a piece of me right now[?]"; (4) shortly after the initial encounter, the temporary employee approached Kelly and the two men exchanged words; (5) Kelly pushed the temporary employee into a cabinet; and (6) the temporary employee punched Kelly in the face.

The commissioner's representative relied heavily on a written statement given to the police by an eyewitness to the events, noting that the statement was "persuasive and determinative" and that there was no evidence to suggest that the witness would not give an accurate statement. Because Kelly initiated the physical confrontation, the commissioner's representative concluded that he was disqualified from receiving reemployment insurance benefits.

Kelly claims that the commissioner's representative wrongly relied on hearsay. But hearsay statements are admissible in reemployment insurance proceedings. See Youa True Vang v. A-1 Maintenance Serv., 376 N.W.2d 479, 482 (Minn. App. 1985) (allowing commissioner's representative to consider hearsay).

Kelly also argues that the commissioner's representative improperly balanced the credibility of the witnesses' testimony, citing Markwardt v. State, Water Resources Bd., 254 N.W.2d 371, 374 (Minn. 1977) (stating that agency's decision is arbitrary and capricious if it represents agency's will not its judgment). But "[a] decision regarding the credibility of witnesses rests within the discretion of the Commissioner, and the testimony should not be reweighed on appeal." Youa True Vang, 376 N.W.2d at 482 (citation omitted). Because the record contains evidence reasonably tending to support the factual findings of the commissioner's representative, we will not disturb them.

A physical confrontation generally is misconduct. Shell v. Host Int'l (Corp.), 513 N.W.2d 15, 18 (Minn. App. 1994). Employers have a right to expect their employees not to fight physically at work. Hines v. Sheraton Ritz Hotel, 349 N.W.2d 329, 330 (Minn. App. 1984). Because Kelly was involved in a physical confrontation with another employee, the commissioner's representative did not err in concluding that he committed misconduct that disqualified him from receiving reemployment insurance benefits.

Kelly also makes three constitutional arguments. First, he argues that the decision of the commissioner's representative violates Minn. Const. art. I, §§ 1 (concerning object of government), 2 (protecting citizen's rights and privileges). Although Kelly cites several principles of law concerning reemployment insurance benefits, he cites no authority supporting his claim, and we decline to address it. See State by Humphrey v. Modern Recycling, Inc., 558 N.W.2d 770, 772 (Minn. App. 1997) (stating that issue unsupported by argument or authority will not be considered).

Next, Kelly claims that the decision of the commissioner's representative violates Minn. Const. art. I, § 8 (providing for redress of injuries or wrongs), citing Wirig v. Kinney Shoe Corp., 448 N.W.2d 526, 530 (Minn. App. 1989) (stating that employer may be liable for battery perpetrated by its agent under certain circumstances), aff'd in part, rev'd in part, 461 N.W.2d 374 (Minn. 1990). But "the purpose of article I, section 8 of the Minnesota Constitution is to preserve remedies under common law." Johnson v. State, 478 N.W.2d 769, 773 (Minn. App. 1991) (citation omitted), review denied (Minn. Feb. 27, 1992). Because a reemployment insurance proceeding is not a forum for bringing common-law claims, this constitutional provision is inapplicable.

Finally, Kelly argues that the amended decision of the commissioner's representative violates Minn. Const., art. I, § 11 (prohibiting ex post facto laws). In that decision, the commissioner's representative applied a statutory amendment that was effective March 5, 1998, which was overlooked in his original decision. See 1998 Minn. Laws ch. 265, §§ 31 (amending Minn. Stat. § 268.105, subd. 3a(d) (relating to disqualification from benefits)), 47 (providing effective date). But the prohibition against ex post facto laws is limited to those involving punishment for crimes. See Starkweather v. Blair, 245 Minn. 371, 386-89, 71 N.W.2d 869, 879-81 (1955) (stating that ex post facto law "renders an act punishable in a manner in which it was not punishable when it was committed") (footnote omitted). Thus, this provision of the constitution is also inapplicable.

  Affirmed.