(CNN)A puzzling incident that sent seven people to a hospital and prompted a hazardous material team to descend on a gas station in Minnesota turned out to have a very harmless origin.
A gas station employee felt a burn when someone handed her cash. Then, 7 people had to go to a hospital
Someone walked into a Cenex station in Minnesota's Mahnomen County on Monday and paid for an item with cash. The cash was coated with a white powder-like substance.
As soon as the employee handled the money, she felt a burning sensation, the sheriff's office said.
A paramedic who happened to be on the scene rushed the cashier to wash her hands. But the sensation didn't go away.
The woman drove herself to the hospital. A hazardous material team descended and sent six others, who were inside the store, to hospital as well -- as a precaution.
All seven were later released from the hospital.
The incident quickly made national headlines because of two questions:
What was the substance, and who was the person who handed it to the cashier?
On Tuesday, the Mahnomen County Sheriff's office had some answers for CNN.
The cash had some carbohydrate on it -- and the cashier was allergic.
"We knew it wasn't airborne because the only person with symptoms was the cashier who held the money, the other employees were perfectly fine," Sheriff Doug Krier told CNN.
"She had to be allergic to the powder, as all the symptoms matched an allergic reaction. We just had to make sure that is wasn't a threat to others."