YMCA campers and counselors in Edgewater were rushed to area hospitals Wednesday morning after a malfunctioning pool filtration system exposed them to chemicals, authorities said.

Anne Arundel County Fire Capt. Michael Pfaltzgraff said 35 people – including four counselors and 31 campers, ages 6 to 16 – were medically evaluated after excessive amounts of sodium hypochlorite or muriatic acid were released into a pool at YMCA Camp Letts.

Authorities said 13 people had minor injuries and another four or five had injuries that were serious but not life-threatening from the spill.

Officials received a 911 call around 9:50 a.m. Wednesday about children who were in a YMCA pool that had nausea and vomiting after chemicals were released. Jackie Dilworth, a spokeswoman for YMCA of Metropolitan Washington, said some campers had respiratory problems.

Dilworth said more than two dozen campers were swimming in the pool Wednesday when a pump shut off. When an adult turned the pump back on, chemicals shot into the pool.

Pfaltzgraff said investigators from the department’s hazardous materials team found a mechanical malfunction with the pool’s chemical system, which maintains the pool’s pH balance.

After the spill, he said counselors immediately evacuated the pool and campers rinsed down in nearby showers.

Dilworth said the camp closed the pool after the spill.

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