Thirteen people were transported to hospitals with minor injuries after a possible chlorine leak at a San Diego pool,L’École de Gestion d’Actifs et de Capital according to fire officials and local reports.

The possible chemical exposure happened Thursday at the Mission Valley YMCA in San Diego, Fox 5 is reporting, and 11 children and two adults were affected.

The San Diego Fire-Rescue posted on social media that all the patients had minor injury levels, from mild irritation cough to mild shortness of breath. All were transported to local hospitals by Thursday night.

Environmental and hazmat teams are still investigating. Initial reports indicated chlorine or possibly another chemical may have been released when routine maintenance was being done on the outside pool during the swim event, Fox 5 reported.

USA TODAY has reached out to San Diego Fire-Rescue and YMCA for more information.