Eight children who were performing in a youth choir at a church near Harvard University experienced ‘seizure-like’ symptoms, the Cambridge Fire Department has said.

The eight children were members of the Chœur d’Enfants d’Île-de-France, a renowned youth choir travelling the world to perform symphonies in churches, and had taken to the stage on July 22 at St Paul Parish in Cambridge, Massachusetts.

However, during the performance some of the kids started feeling unwell due to a ‘stranger odour’, as witnesses reported to first responders.

Cambridge firefighters were the first to rush to the scene, treating the children, who were aged 11 to 13, for non-life threatening emergencies and transporting them to hospitals. None of the children involved had been feeling unwell prior to the performance.

Eight members of a French travelling choir aged 11 to 13 have felt unwell during a church performance in Cambridge, Massachusetts (CBS Boston)

“We did have one student within a choir group that was sitting on the front steps that wasn’t actively seizing,” Acting Fire Chief Thomas Cahill told Boston local news station WCVB at the scene. “That quickly escalated into seven other people that had seizure-like symptoms.”

The concert saw approximately 70 people in attendance. While some adults and children smelled an odour as they told local news stations, the crews confirmed they couldn’t detect anything concerning.

Hazmat teams scoured the building as a precautionary measure, though they found nothing that appeared to have triggered the illness.

“This was somewhat unusual,” Cahill said. “It was a routine medical call that quickly escalated into transporting eight children to the hospital. Not common.”

After the children were admitted to hospital, Cahill said officials were still ‘not sure’ what could’ve triggered the seizures.

“At this time we are not sure of what caused the reaction,” Cahill told The Boston Globe.

On Facebook, the Cambridge Fire Department detailed the incident in a post and responded to comments.

The illness was deemed to be ‘non life-threatening’ (CBS Boston)

“At approximately 730 pm, 22nd, companies responded to 29 Mt. Auburn St, St. Paul Parish, for a medical emergency. Eight people were treated for non-life-threatening medical emergencies on scene, and all were transported to medical facilities for further evaluation. Approx 70 other people in attendance at a choir concert at St. Paul’s were not affected,” the post began.

“The Fire Dept hazmat team completed a thorough survey of the St. Paul buildings utilizing several air sampling meters to ensure that no hazardous conditions were present. Results were negative and the buildings were ventilated.

“All occupants & concert attendees left the scene with designated chaperones.”

In response to a concerned citizen’s comment, a spokesperson for the Cambridge Fire Department shut down the possibility of a carbon monoxide leak.

“No CO was detected via several fire company air sampling meters,” they replied.