It may have stemmed from sodium hypochlorite exposure, a report said

the water at the park

Testing is being carried out

An Antioch, California, water park was shut down this week following many people falling ill there.

The incident took place at the Prewett Family Park on Thursday afternoon and mainly affected children, according to reports.

Battalion Chief Bob Atlas with the Contra Costa County Fire Protection District said in a Friday news release firefighters 'responded to a report of 10 to 12 children getting sick from drinking pool water at the Antioch Water Park at 4701 Lone Tree Way in Antioch.'

Scroll down for video

Scare: A water park in Antioch, California was shut down this week, after many people fell ill there

Victims: The incident took place at the Prewett Family Park on Thursday afternoon and mainly affected children, according to reports

Atlas said 'After carefully assessing the incident it was found that more patients were coming forward.'

He also wrote that 'A total of 34 patients were treated, 17 were transported to area hospitals and 17 were released to their legal guardians.'

NBC Bay Area reported testing is being carried out on water at the park.

According to the television station, the park -- save for its Sport Pool -- was set to open on Saturday.

The website for the Antioch Parks and Recreation Department said Saturday 'The Sport Pool is closed today due to maintenance.

'We apologize for any inconvenience.'

'The children started feeling respiratory distress, and it appeared to be related to some form of chemical, probably chlorine,' Capt. George Laing told the San Francisco Chronicle on Thursday.

Battalion Chief Bob Atlas has said 'A total of 34 patients were treated, 17 were transported to area hospitals and 17 were released to their legal guardians'

Officials: A worker with Contra Costa Hazmat Health Services is spied at the scene

'I can confirm that very recently... there may have been a chlorine delivery that may have been related to the incident,' he also told the newspaper.

ABC News reported Thursday's incident may have stemmed from sodium hypochlorite exposure. Sodium hypochlorite is a disinfectant.

Contra Costa chief environmental health and hazardous materials officer Randy Sawyer told ABC News 'We are concentrating on the storage and delivery of the sodium hypochlorite into the pool.

'We believe that changes do need to be done with this system and that by making these changes it may prevent such an exposure that occurred yesterday.'

Closure: The park was caught on camera saying it was closed for maintenance