At least 16 people were hospitalized over the weekend, two in critical condition, after attending a music event Friday night at Daly City's Cow Palace, a North County Fire Authority battalion chief said.
The event, radio station Live 105's "Subsonic Spookfest," headlined numerous electronic music artists and was open to partygoers ages 16 and older, according to the Cow Palace events listing.
All the victims were being treated for drug-and alcohol-related overdoses, Battalion Chief Tony Maffei said.
The victims were transported by ambulance to hospitals across San Mateo County and San Francisco, he said.
"We spread them all the way down to (Kaiser Permanente Medical Center-Redwood City) and every hospital in between," Maffei said, noting that victims were also transported as far north as San Francisco General Hospital. "We didn't want to overload any one medical facility."
Maffei said he was called to the scene at 8:30 p.m. with the first of three fire engines now on site, and four people were transported with injuries shortly after his arrival.
Emergency responders from as far away as Alameda County were called in to assist with the partygoers' injuries, including at least one ambulance from American Medical Response, according to a dispatcher with the ambulance company.
This is the second time this year that partygoers have been hospitalized with drug-related injures following a large music event at the Cow Palace.
Five months ago to the day, nine victims were hospitalized following the "etd.POP 2010" music festival on May 29. Two of those patients eventually died as a result of their injuries.
Police suspected those illnesses were cause by overdoses of the drug Ecstasy, Daly City police Lt. Jay Morena said in May.
Those overdoses also sparked a debate among county officials and police as to whether or not to institute a ban on raves at the venue.