Chapel Hill, N.C. — The kitchen at Smith Middle School was vandalized last week, and the vandals urinated in the ice machine, according to a letter sent to school staff and parents of students.

The vandalism occurred Dec. 15, and school officials said the ice machine was used Tuesday, Wednesday and Thursday, officials said. Ice from the machine is used to chill containers on the lunch serving line and is used in drinks by students and staff, officials said.

After learning of the possibility of tainted ice, Smith Middle officials said, they removed all ice from the machine and any items that might have come in contact with the ice.

The Orange County Health Department said there is no known health risk to anyone who might have consumed tainted ice. Public health officials also were instructing the school on how to properly clean and disinfect affected surfaces and equipment before using them again.

Chapel Hill-Carrboro City Schools officials have referred the case to Chapel Hill police for possible criminal charges.