Six children are in serious condition following a chemical leak at a Durham YMCA that injured about forty people this afternoon, according to Durham officials.

According to a Durham County spokesperson, thirty-seven children and two adults were hurt. The Durham Police Department says forty children and two adults were affected.

In a statement, county spokesperson Dawn Dudley identified the chemical released as hypochlorite, “a chemical used for everyday maintenance of swimming pools.” Six of the children — ages six to twelve years old — are in serious condition, Dudley said. DPD says their injuries are not life-threatening.

The spill occurred at about three p.m. and the pool has been closed. The West Mangum Street YMCA announced just before four p.m. that it was closing “due to unforeseen mechanical issues.”

Durham County Emergency Management, as well as other first responders and a HAZMAT team are at the downtown facility, which was evacuated. Injured guests have been transported to Duke University Hospital and Duke Regional Hospital.

According to WRAL, EMS was called after children swimming in the pool began having trouble breathing. In a statement, Durham police said those transported to hospitals were “exhibiting symptoms such as vomiting, respiratory illness and skin and eye irritation.”

Several streets downtown have been closed during the response.