Two children from Pennsylvania are fighting for their lives after drinking apple juice tained with some sort of caustic substance at a buffet on Friday, according to local news site Lancaster Online. Half-siblings Richie Zaragoza, 10, and Ginaya Mendoza, 4, were sent to Hershey Medical Center where they are in critical but stable condition.

They had been celebrating Richie’s birthday with their family at Star Buffet and Grill when Ginaya began vomiting after drinking the juice. Richie started throwing up blood and saying that his throat was burning, prompting them to be rushed to Hershey Medical Center where they were sent to the intensive care unit.

Initial tests have uncovered methanol in the tainted juice, but investigators are still working to identify all the elements in the juice.

“Most methanol poisonings occur as a result of drinking beverages contaminated with methanol or from drinking methanol-containing products,” according the CDC.

The manager of the restaurant reportedly purchased the juice from a local supermarket.

“I had to try to talk to him [Richie] last night through his fingers,” Richard Zaragoza, his father, said in the Lancaster Online report. “I told him I loved him … and he squeezed my hand twice so he was responsive.”

It will be a long and slow recovery process, and Richie will not be able to eat food for a week, the doctors are telling the family. It’s possible that the children had severe reactions from drinking the juice from foam cups. No other diners had any reported discomfort, according to the report.