Children at an Alaskan school were mistakenly served floor sealant instead of milk, school officials said.

An investigation is underway at Glacier Valley Elementary School in Alaska, after a dozen students and two teachers were served floor sealant instead of milk, school officials said.

According to USA Today, The children at Sitʼ Eeti Shaanáx̱ Glacier Valley Elementary School in Juneau complained of burning sensations in their mouths and throats and said the milk tasted bad after being served on Tuesday, the school district said in a statement.

The investigation found that an outside contractor with the NANA management service (NMS) was responsible for making breakfast at the RALLY summer care program. When they ran out of milk, staff was sent to get more from their school warehouse where extra food is stored.

After the children alerted staff of the bad tasting milk, school officials say the staff “immediately smelled and tasted the ‘milk’ and looked at the container labels.”

Once RALLY staff and the outside contractor from NANA management service realized the mistake, they immediately called poison control, the district said. “Staff immediately directed students to stop consuming the substance and removed it.”

Parents were not immediately notified of the mistake and instead found out about the mistake from other people. Despite delayed communication, parents were able to contact medical care providers to get their children evaluated as quickly as possible.

As of Wednesday evening, all students were reported to be recovering from nausea and headache and some had made a full recovery.

“The Juneau School District Board of Education was appalled to learn of the food service error that occurred earlier this week,” the district said in a statement. “Our immediate priority is with the students impacted by the incident and ensuring their recovery and continued safety.”

The investigation as to how the boxes of sealant were mixed up with food storage is still ongoing and the board has stated they will continue to work with the school district, City and Borough of Juneau, NMS, Alaska’s Department of Environmental Conservation and the Juneau Police Department to make sure proper protocols are put in place to ensure the safety of their students.

What the district is doing?

According to reports, all sealant has been accounted for and stored in its proper place away from food service areas.

“On Wednesday, the facility and operations were inspected by the State of Alaska Department of Environmental Conservation (DEC) Food Safety and Sanitation Office. DEC Food Safety approved the facility for continuing operations,” the district statement said.

DEC is also conducting in internal investigation and is expected to follow up with recommendations and protocols to prevent this from reoccurring.

The district is also taking accountability for the delayed response to parents and working to enhance their alert systems to create quicker communication protocols for parents.

“There was a delay in parent notification which was longer than it should have been. This caused families to learn about the situation from other people, which is not best practice,” the district statement said.

The Juneau School District Board of Education will hold a special public meeting on Friday, June which representatives of NMS will attend, it said.