Electric Zoo, an electronic music festival that takes place every Labor Day weekend on Randall’s Island in New York, was abruptly shut down before its third day due to serious health risks. The health risks referred to were of two concertgoers who died and at least four others who had fallen critically ill during the first two days of the event.

According to the New York Times, the mayor’s office saw the safest course being to cancel the remaining days of the festival although the festival organizers and city officials had worked together to reduce the health risks at the event. The city announced that the deaths appeared to have been linked to drugs although the definitive causes have yet to be determined. The four others hospitalized are assumed to have suffered from similar causes.

The festival was entering its fifth year and drew over 100,000 people to the island. Big EDM acts such as Avicii and David Guetta along with over 100 musical acts were scheduled to perform. The event’s founders expressed their condolences on its website to the families of those who died. The music festival was previously scheduled to run from Friday through Sunday night.