Nearly 20 people suffered from chlorine poisoning Wednesday evening after an equipment malfunction at a swim school in Thousand Oaks, authorities said.

Firefighters were dispatched shortly after 6 p.m. when swimmers started having difficulty breathing at the Daland Swim School at 135 E. Wilbur Rd., said Ventura County Fire Capt. Brian McGrath. Authorities said an equipment malfunction began pumping extra chlorine into a pool.

A dozen people were were taken to hospitals, while seven others were evaluated or treated at the scene, according to the Fire Department. McGrath did not know their ages or whether there was a swimming class in session.

Seven ambulances and four fire engines responded to the school.


The Fire Department urged drivers to avoid the area.

#WilburInc: tonight there was an accidental release of pool chemicals at a swim club in @CityofTO . Update from video: 19 pts. total. 12 xported to local hospitals. Some uninjured patients have been released to parents or family members. Cause still under investigation. @VCFD pic.twitter.com/zdVLlALR5f — VCFD PIO (@VCFD_PIO) October 4, 2018

alene.tchekmedyian@latimes.com

Twitter: @AleneTchek


UPDATES:

10:20 p.m.: This article was revised with updated patient numbers.

This article was originally published at 7:30 p.m.