Two women died from what authorities called a suspected drug overdose after collapsing at the HARD Summer music festival in Pomona, California, the Los Angeles Times reported. The women, ages 18 and 19, were transported to hospitals after being found unresponsive during the festival, the Los Angeles County coroner’s office said, but it was unclear if they were connected to each other.

The two were pronounced dead at the hospital late Saturday. The 18-year-old died at approximately 6 p.m., local time, KABC, Los Angeles, reported. The 19-year-old died around 8 p.m. The names of the women were withheld pending notification of relatives. Autopsies are to be conducted to determine the cause of death in each case.

If it was a drug overdose, then the two women are the latest in a series of overdoses that have plagued music festivals. In June, a 24-year-old man from San Francisco died during the Electric Daisy Carnival at the Las Vegas Motor Speedway from an overdose of Ecstasy. In May, a 20-year-old died at a rave in Tacoma, Washington, from an overdose of the popular festival drug Molly, which is often cut with a mix of chemicals and other drugs.

Oscar Mendez, 19, said drugs are part of the culture of the festival scene, the Times reported. "It is unfortunate that this kind of tragedy happens. People get carried away," Oscar Mendez, 19, said. "People try to fit in and they don't know their limits.”

HARD Summer is an annual music festival. This year, 65,000 people were expected to attend each day of the sold-out, two-day festival, the Times said. Those numbers make the festival the largest of its kind in Los Angeles County.

Michael D. Antonovich and Hilda Solis, two Los Angeles County supervisors, said Sunday they will seek an investigation of the event to determine if it was properly managed to ensure guests’ safety.