Swimming pool chemicals created a gas cloud that sent dozens of people to local hospitals in California on Thursday after maintenance workers mixed muriatic acid and chlorine, authorities said.
At least 35 people were exposed to the gas cloud at the Shadow Brook Swim Club in Almaden Valley in residential San Jose, the East Bay Times reported. The incident happened shortly after noon when the acid-chlorine combination created the gas cloud.
Officials said the victims were transported to nine different hospitals.
"We are taking this very seriously," San Jose Fire Capt. Mitch Matlow told the Times. "That combination of chemicals can release a gas cloud that can cause what's called secondary drowning. The lungs start swelling up with its own fluid, the fluid blocks the airwaves and you drown in your own fluids."
KGO-TV reported that a swim class was in session at the community pool when children and adults became sick.
Pediatrician Michelle Contini told KGO-TV that two victims were vomiting while two others were having difficulty breathing, both symptoms of chlorine gas exposure. She said her 19-year-old son works as a lifeguard at the swim club.
Matthew Dworkin, 17, a swim instructor and member of the swim team, told the Times that it still hurt for him to breathe and he felt nauseated after being released from Kaiser Permanente in San Jose. He said he was teaching a swim class when people were overcome by the gas.
Rip Nahal, 40, was treated at San Jose Regional Medical Center and released along with her three children, ages 5, 8, and 10, who were taking swim lessons. She told the Times that she felt "tightness of the throat" and a "burning nose" during the incident.
The Centers for Disease Control and Prevention website said chlorine, commonly used in water to kill germs and stop them from spreading, can become an irritant for some users.
"Healthy pools and other places where we swim in chlorinated water don't have a strong chemical smell,” the CDC website said. "If you smell 'chlorine' at the place you swim, you are probably smelling chloramines.”
"Chloramines in the water can turn into gas in the surrounding air. This is particularly a problem in indoor pools, which often aren't as well-ventilated as outdoor pools. The chloramines that form in the chlorinated water we swim in are different from the chloramine that is sometimes used to treat drinking water."
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