Sixteen people were hospitalized and 40 were arrested at a Halloween-themed rave at the Los Angeles Sports Arena, authorities said Sunday.
More than 12,000 people attended Monster Massive, a five-stage party that organizers called "America's Largest Halloween Dance Music Festival," from 3 p.m. Saturday to 3 a.m. Sunday, fire officials said.
The condition of the seven people paramedics took to local hospitals was not immediately available, said Los Angeles Fire Department spokesman Erik Scott.
Most arrests were made on charges of narcotics possession and trespassing, according to the Los Angeles Police Department's Southwest Station.
Safety concerns and the death of a 15-year-old girl from an Ecstasy overdose at the Electric Daisy Carnival in June prompted a temporary ban on new raves at the Los Angeles Memorial Coliseum and Sports Arena.
Monster Massive was one of three planned raves permitted to go forward with stricter oversight, including a ban on minors.
[UPDATED 3:30 p.m.: Paramedics treated 37 patients at the rave and 16 were taken to hospitals by fire department and private ambulances. Officials revised the numbers after conducting a complete analysis of their data, said Scott.]