The final day of the Electric Zoo music festival in New York City was cancelled Sunday after two attendees died and four more were in critical condition, all thought to be connected to the popular club drug MDMA. 

The exact cause of death is unknown, but "both appear to have involved the drug MDMA (ecstasy, or molly)," according to a statement from the mayor's office. The city claims they recommended the event be cancelled and the organizers agreed. The New York Post reports 23-year-old man and a 20-year-old woman died Saturday after being rushed to hospitals from the festival grounds. 

Electric Zoo began on Friday on Randall's Island and was supposed to run well into Sunday night, with Armin Van Buuren, Steve Aoki and Diplo expected to perform. Festival organizers released this statement Sunday morning, per Gothamist

"The founders of Electric Zoo send our deepest condolences to the families of the two people who passed away this weekend. Because there is nothing more important to us than our patrons, we have decided in consultation with the New York City Parks Department that there will be no show today."

Electronic dance music, or EDM, is often connected to MDMA's rise as the trendiest drug going right now. MDMA, or "molly," is supposed to be a purer version of Ecstasy. The drug has become so culturally ubiquitous, thanks mostly to EDM and a recent surge of popularity in hip-hop, that it even warranted a New York Times' Style section trend piece. This also isn't the first time molly has been connected with deaths or injuries following major electronic music festivals. 

A few DJs have commented on the cancellation on Twitter: 

And some members of the press weighed in on the news, too: 

Whether or not the deaths at Electric Zoo will be some kind of tipping point, leading kids away from taking molly when they listen to dance music, or at all, remains unclear. It doesn't seem likely, though.