Restaurant's Toxic Tea Leaves Woman in Critical Condition

— -- A woman is in critical condition after taking a simple sip of toxic iced tea at a Utah restaurant.

Jan Harding, 67, was eating at a Dickey's Barbecue Pit with her husband, Jim. She sipped her tea and started gagging and coughing, Jim Harding said.

"I said, what is wrong?" Jim Harding said. "She said, 'I just drank acid.'"

The tea contained a heavily toxic industrial cleaner. The cleaner, made up of sodium hydroxide, or lye, is known to cause severe burns to the mouth, throat and stomach if swallowed -- chemical burns that Harding suffered from one drink.

Her husband watched as emergency crews tried to help.

"There was terror in her eyes," he told ABC News. "I said, 'I love you.' And she couldn't talk at that point, just mouthed, 'I love you, too.'"

Police were interviewing employees and checking surveillance cameras, but authorities initially believed it was an accident -- that the powdered cleaner may have been mixed in by an employee who mistook it for sugar, which has a similar appearance.

Harding underwent an endoscopy Thursday, which revealed more extensive burns than the family expected, according to a statement from Harding’s attorney.

"The scope revealed deep ulcerated burns covering the upper area of her esophagus. There are also severe burns throughout her mouth and throat," Paxton Guymon said in a statement. "The news was very disappointing and disheartening for the family."

Barbara Insley Crouch, the executive director of Utah's Poison Control Center, said Harding's suffering is profound.

"You can imagine it would burn the tissues in your mouth and down into your esophagus and down into your stomach," Crouch said.

The franchise owner of the restaurant released a statement following Harding's hospitalization expressing concern.

"At this time we are fully involved in cooperating with all parties," the statement read.

Health Department officials said despite the situation, the restaurant was safe for customers, and remained open for business. Police said no one else was hurt -- that it was a fresh batch of iced tea and Harding seemed to have been the first person to try it.

Jim Harding hoped a lesson is learned from his wife's situation.

"If the people in the restaurant industry could just be made aware of the potential danger, it's worth it," he said.