Ambulances standing by to transport kids and adults possibly exposed to chlorine gas at community pool on Shadow Brook Dr #sanjose. No serious injuries but all were decontaminated onsite then transported to area hospitals. #abc7now pic.twitter.com/1gYqB1Dmjd — David Louie (@abc7david) June 14, 2018

Himmat Nahal (age 10), sister Amrit (5) & brother Arjan (8) were taking a swim lesson when chlorine gas began making them and others sick at Saddle Brook Swim Club #SanJose Thursday afternoon. They were decontamined twice; examined at hospital and OK now. #abc7now pic.twitter.com/4XU7uPtqOB — David Louie (@abc7david) June 14, 2018

Update: 35 kids & adults sent to hospitals after visible cloud of yellowish chlorine gas spread at Shadow Brook swim club #San Jose. 2 victims were vomiting; 2 others short of breath. Both are symptoms of chlorine gas exposure per pediatrician on scene. #abc7now pic.twitter.com/u8MYcYKTNu — David Louie (@abc7david) June 14, 2018

SOUTH SAN JOSE, Calif. (KGO) -- A swim class at an Almaden Valley community pool in San Jose was interrupted just after 12 p.m. Thursday when a chlorine gas cloud formed and began making both kids and adults sick.Someone in the pump room at the Shadow Brook Swim Club mistakenly mixed chlorine with muriatic acid, agents used to sanitize pool water, which created a yellow cloud of chlorine gas.San Jose Fire public information officer Mitch Matlow said two victims were vomiting while two others were having difficulty breathing. Both are symptoms of chlorine gas exposure, according to pediatrician Michelle Contini, whose 19-year-old son Zach works as a lifeguard at the swim club. Contini offered her help, but was turned down.A total of 10 ambulances responded to the scene to transport 35 victims altogether. The injuries were considered minor in most cases. Firefighters initiated a mass casualty response, which included decontamination of the kids and adults exposed to the gas. That involves hosing them down with a lot of water. The victims were then taken for further examination to nine hospitals as far north as Stanford Medical Center and throughout the Santa Clara Valley. Matlow said that is done not to overwhelm one single hospital.Contini told ABC7 News that symptoms can appear on a delayed basis, sometimes a couple of hours later.The exact breakdown of how many kids and how many adults were exposed to the chlorine gas was not immediately available.Shadow Brook Drive is open, but fire personnel are standing by to measure the air for traces of the gas before allowing access. No shelter in place was ordered for the residents living around the swim club.