One man died and 23 people were hospitalized after attending the Hard Summer music festival this weekend in Fontana, Calif. at the Auto Club Speedway.

Andrew Cole, 19, of Tracy, California, was pronounced dead at a local hospital Sunday night. No cause has been revealed, but authorities said an autopsy will be used to determine the cause of death.

The 23 people hospitalized were treated for various medical issues. Two women remain in the hospital and continue to receive treatment. Eleven people were arrested, mostly for drug offenses, according to the San Bernardino County Sheriff’s Department.

More than 80,000 people attended the event on Saturday, and more than 70,000 attended on Sunday. The headliners for the event included Marshmello, Travis Scott, Louis the Child, and Rick Ross.

The festival’s organizers issued a statement. “It is with great sadness that we have learned a festival attendee has passed away following Hard Summer this weekend. We extend our deepest sympathies to the individual’s loved ones, and we ask that you keep them in your thoughts. The health and safety of those who attend our events is Hard’s utmost priority, and we take every measure to create a safe and enjoyable environment. We have no further information at this time, but we encourage the community to come together, support each other, and always look out for one another in light of this tragedy.”

The Sheriff’s Department said many of the hospitalizations and other medical issues were related to the extreme heat, which reached over 100 degrees.