At least sixteen people were injured after an explosion at an FBI training facility on Wednesday.

The incident happened at the Jerry Crowe Regional Tactical Training Facility in Irvine shortly before 1 p.m., according to the Orange County Sheriff’s Department.

The explosion happened as the OCSD SWAT Team was conducting a joint training exercise with a bomb squad, authorities said.

Sixteen SWAT team members were injured by the blast — 15 people were transported by ambulances to local hospitals for treatment while one person was able to self-transport.

Some of the reported injuries include non-life-threatening wounds to the legs and back, with one person requiring surgery. At least 13 people were experiencing dizziness and ringing in the ears. The exact nature of everyone’s injuries is not yet known, but no deaths have been reported.

Authorities said a canister of some sort exploded during the annual joint training exercise. A small building where the blast ignited inside was seen cordoned off by police tape. It’s unclear what exactly triggered the canister to explode.

Sky5 footage captured a robot situated outside of that small building as some debris was seen strewn near the entrance.

“We do have two members of our SWAT Team who are cross-trained as paramedics and they were able to provide assistance immediately,” authorities said.

The Irvine FBI training facility is located at the former El Toro Marine Corps air base grounds.

The O.C. Sheriff’s Department, along with the FBI, will be investigating the incident.

Footage of the scene can be viewed in the video player above. This developing story will be updated.