Fourteen people were hospitalized during an outdoor concert by The Chainsmokers in downtown San Jose after a sudden wave of medical emergencies prompted firefighters to deploy more than a dozen ambulances during the final stretch of the performance.

The San José Fire Department began receiving multiple medical calls at approximately 8:22 p.m. Friday, Sept. 4, as the electronic duo performed at Discovery Meadow.

The emergencies occurred during roughly the final 30 minutes of the show.

As the number of patients requiring medical attention increased, emergency officials requested an Ambulance Task Force along with additional advanced life-support resources to handle the surge.

Fourteen ambulances ultimately transported 14 patients from the concert to local hospitals.

Authorities have not reported any deaths.

Emergency Calls Surge Near End of Concert

The response escalated rapidly after firefighters began receiving medical calls from the concert grounds.

Discovery Meadow, located next to the Children's Discovery Museum in downtown San Jose, was hosting a large outdoor crowd for The Chainsmokers' performance when multiple attendees began requiring assistance.

The volume of calls prompted officials to bring in additional emergency resources rather than relying on the medical personnel already assigned to the event.

Fire officials said the Ambulance Task Force was requested because of the number of patients needing immediate transportation to hospitals.

By the end of the response, 14 separate ambulances had been used to transport patients.

Officials did not immediately release the ages of those hospitalized or detailed information about their conditions.

There has also been no indication that the patients were all suffering from the same medical problem.

That distinction is important.

While the number of hospitalizations made the incident unusual, authorities have not announced evidence of a single event—such as a crowd crush, contaminated substance or other shared exposure—responsible for all 14 cases.

Instead, the San José Fire Department described responding to multiple medical emergencies occurring within a relatively short period.

Concert Continued as Emergency Crews Responded

The Chainsmokers' performance was part of San Jose's 2026 Summer Concert Series, which brought large-scale outdoor music events to Discovery Meadow.

The Grammy-winning electronic duo of Drew Taggart and Alex Pall took the stage Friday night before the medical calls began escalating late in their set.

Emergency crews treated patients as the performance moved toward its conclusion.

There has been no public indication that the concert itself was formally evacuated because of the incidents, and officials have not reported a broader public-safety threat at the venue.

The Chainsmokers have not publicly been accused of wrongdoing in connection with the hospitalizations.

The incident instead appears, based on the information released so far, to have involved an unusually concentrated series of individual medical emergencies during a large outdoor event.

Cause of Medical Emergencies Remains Unclear

The biggest unanswered question is why so many concertgoers required hospital treatment within such a short period.

Officials have not released detailed diagnoses for the 14 patients.

There has been no confirmed report establishing drugs, alcohol, heat, dehydration or another specific factor as the common cause of the hospitalizations.

Without that information, describing the incident as a poisoning, overdose event or crowd-related disaster would go beyond what authorities have established.

What is confirmed is the scale of the emergency response.

Beginning at approximately 8:22 p.m., San Jose firefighters encountered enough patients requiring immediate medical attention that additional ambulances and advanced life-support personnel were called to Discovery Meadow.

Fourteen people were eventually taken to hospitals.

For now, officials have not publicly identified a single explanation connecting those medical emergencies.