The progress marks the first sign of improvement for Jan Harding since the 67-year-old was rushed to a hospital nearly a week ago with severe burns to her mouth and throat, according to family attorney Paxton Guymon.
The heavy-duty cleaner that ended up in the sweetened iced tea Harding drank Sunday at a Dickey's Barbecue in a Salt Lake City suburb was unintentionally mixed into a bag of sugar, which a worker later added into the iced tea dispenser, authorities have said.
Harding's breathing tube has been removed, and she was doing well without it, Guymon said in an email.
She had not been able to speak in days, nor had she been on her feet before standing briefly with the help of nurses, according to Guymon. "Everyone is more optimistic today," he wrote. "Any such sign of improvement is good news."
Her husband and their three adult children have been at her bedside, praying for her recovery from the deep, ulcerated burns in her upper esophagus that have left her in critical condition at a Salt Lake City hospital.
The cleaning product is meant for degreasing deep fryers and contains the odorless chemical lye, the active ingredient in drain cleaners.
South Jordan Cpl. Sam Winkler said police are waiting to see what happens with Harding's condition before moving forward with any arrests or charges.
Dickey's Barbecue Restaurants Inc. said in a statement late Friday that it was an isolated incident and nothing like it had happened in the 73 years the Dallas-based chain has operated.
"There is nothing more important to us than the trust and safety of our guests," the statement said, adding that the franchise owner, John Thomson, was deeply saddened and is cooperating with authorities.
Police have determined Harding was the only victim, Winkler said. It appears she was the first to drink the tea, and Dickey's employees disposed of it after she was burned, he said.
The establishment remains open after county health officials inspected it and found all chemicals properly labeled and separated from food items.