Ten teenagers were treated for second and third degree burns after someone unleashed white paint and unknown chemicals on them during a basement party in the East Village on Saturday night. On May 4th, more than 300 high school students reportedly attended a party in the basement of a New York City Housing Authority apartment building in the East Village. As some of the partygoers gathered in a courtyard outside the basement, an unidentified individual poured an “unknown liquid caustic substance” down on them, an NYPD spokesperson told Gothamist.

The Saturday night fete had been advertised on social media and charged a $10 cover. Tenants’ association president Heyward Walker told the Times he had not rented out the basement room—which is usually used for tenant meetings—to the young man who threw the party. Tenants at the First Houses development off Third Street do not believe the party host is a fellow resident in the building, according to the Times.

“It was nuts,” resident Michael Strachan told the Times. “I came home and there were all of these teenagers and smashed beer bottles everywhere, all of these cop cars were here, nobody knew what was going on.”

According to reports, many of the party attendees are students at Brooklyn Technical High School. Valerie Vail, the mother of a sophomore at the school, told the Times her daughter suffered quarter-sized burns on her back, chest, and arms, and that other students had even larger burns on their necks and legs.

Following the incident, some of the victims ran to a nearby deli to treat their burns with milk; others were taken to area hospitals for treatment. The injured teens (aged 15 to 18, six girls and four boys), reported “third degree burns to the skin,” according to an NYPD spokesperson. No arrests have been made, and police are still trying to confirm whether the person responsible is a resident of the building.

A NYCHA spokersperson said the agency is working with the NYPD to investigate the incident and has also begun an internal investigation.