A careless mistake made by workers at a Dairy Queen in Colorado sent a 7-year-old boy to the hospital after his mother discovered that a vanilla shake she purchased from the fast food restaurant had been laced with chemical cleaner. Moments after Riley Chase took a sip of his milkshake, he knew something wasn’t right due to the taste and bubbling sensation on his tongue.

"He took a drink of it and then he said, 'mom this shake tastes disgusting,'" Riley’s mother Lisa Chase told 9NEWS. "I took a drink of it, and instantly you knew that was not a vanilla shake. It burned my mouth and my throat. You could feel it burn all the way down to your stomach."

When the concerned mother entered the Thornton, Colo., Dairy Queen after tasting her son’s tainted beverage, she reported that employees did not provide her with an explanation. However, when she called the restaurant upon returning home, she was informed by a manager that an empty bottle of vanilla syrup had been placed next to a sink and was accidently refilled with floor cleaner and degreaser.  

“They could’ve cost people their lives with this,” Chase told FOX8. “You couldn’t even taste the ice cream in it. It tasted like you were drinking a very strong cleanser. Then the burn started instantly. They need to be held accountable for what they’re doing.”

Both mother and son were rushed to a local hospital once Chase discovered they had ingested dangerous chemicals. They were released after being treated for internal burns. Chase would later learn that two other customers of the Dairy Queen required medical attention as a result of chemical-laced milkshakes. Two workers have been written up as a result of the incident.  

“This was an accidental and isolated incident,” read a statement by Dairy Queen that was issued to ABC News. “The employees responsible have been reprimanded. The rest of the staff is getting new training.”