Hard Summer Festival 2016.

Hard Summer Festival 2016.

 

Chelsea Lauren/REX/Shutterstock

The San Bernardino County Sheriff Coroner's Division has officially ruled the cause of death of three attendees at July's HARD Music Festival as ecstasy overdoses.

According to a report by the Fontana Herald News, Derek Lee, 22, Alyssa Domingo, 21, and Roxanne Ngo, 22, passed away of acute MDMA toxicity. There were nine medical transports throughout the two-day event, which hosted about 146,000.

Read more: 3 Dead After HARD Summer Music Festival

This was HARD Summer's first year in the city of Fontana, Calif., following a move from its usual home of Los Angeles. San Bernardino County considered banning electronic music festivals earlier this year but has taken no official action. 

Billboard Dance has reached out to HARD Events for comment.