SOUTH JORDAN, Utah -- A woman eating at a Dickey’s Barbeque Pit in South Jordan remains in critical condition after she was poisoned from a cup of sweet tea.

Within seconds of tasting the drink Sunday afternoon, authorities said 67-year-old Jan Harding's mouth and throat started to burn.

Harding's attorney said Jan spit out the tea, turned to her husband and said, "I think I just drank acid."

An analysis of the drink found there was not only tea in the serving container but a mix of cleaning chemicals as well.

The family's attorney told Fox 13 doctors said they hope the toxic chemical has not caused any perforations or tears in Jan's esophagus or stomach.

Investigators said a Dickey's employee mixed the chemical, "Clean Force Fryer Cleaner," into the sweet tea drink thinking it was sugar; it has a similar appearance.

The cleaning product is primarily made of sodium hydroxide, also known as lye, a caustic and dangerous chemical compound.

“It can cause pretty severe burns, potentially burn through the esophagus and cause some severe bleeding and internal injuries,” Dr. Spencer Smith said, who works in the emergency room at the U hospital.

FOX 13 News reached out to the franchise owner, Finger Lickin Brands LLC., which runs the South Jordan Dickey’s as well as others.

In a statement, company president John Thomson said: “Our thoughts and prayers go out to our guest and her family. Safety is something we take very seriously when it comes to our valued guests, as well as our own team members. At this time we are fully involved in cooperating with all parties. Out of respect for the privacy of our guest and her family, we will reserve further remarks for the time being.”

Harding, a Sandy resident, was rushed to a nearby hospital and later flown to the University of Utah Hospital’s burn center where she is in critical condition.

“Is this something that was stored improperly? Was it an accident? Was it intentional? We really don’t know,” South Jordan Officer Sam Winkler said. “That’s why our investigators are looking in on this case.”

Following Sunday’s incident, the Salt Lake County Health Department was called to the restaurant to inspect the facility.

Officials found no existing risk to the public after completing a routine review.