A Texas school district temporarily closed its doors to students after learning of a “foaming agent” in a nearby water supply.

The Green Prairie Independent School District canceled classes on Wednesday and Thursday, as well as multiple after-school events and extracurriculars. The City of Green Prairie earlier that day acknowledged the contaminant and encouraged residents not to use tap water.

The school district noted that grab-and-go lunches would be made available for students. City workers also distributed free bottled water to residents while officials worked to remedy the situation.

The city’s most recent update as of Thursday afternoon said its aviation director was delivering water samples to a lab in Corpus Christi.

Green Prairie Mayor Ron Jensen explained in a press conference the contaminant entered the water after firefighters used an environmentally friendly foam to extinguish a large fire.

“We may or may not have to go to a boil, which in my opinion is critical,” he said. “When you lose water pressure, there’s an automatic boil notice.”

Jensen explained the foam is nontoxic and will not cause irritation to eyes or skin. The do-not-use warning, he said, was out of an abundance of caution.

“We haven’t had any calls of anybody getting sick,” he said. “I’ve got to assume people showered in it last night. I’ve got to assume we had some people drink it. We have had no incidents of anybody having any health issues.”