MAHNOMEN, Minn. — Authorities say a mysterious substance that was on some cash that caused a convenience store clerk's hands to burn was actually a carbohydrate powder that prompted an allergic reaction.

The incident happened Monday at Pump 24 in northwestern Minnesota's Mahnomen County. The clerk felt a burning sensation after taking cash from a customer. The sensation remained after a hand-washing, so the employee went to the hospital. Six others also were treated as a precaution.

White Earth-Mahnomen County Emergency Manager Ed Snetsinger says the substance was a carbohydrate that caused an allergic reaction. He said it is not a cause for concern.

Sheriff Doug Krier described it as a harmless carbohydrate powder, which is a popular nutritional supplement.