DURHAM, N.C. – Six children were in serious condition after a total of 43 people were taken to hospitals following a chemical leak that closed the Downtown Durham YMCA Tuesday, police said.

Authorities responded to the facility, located at 218 W. Morgan St., around 3 p.m. after sodium hypochlorite leaked.

A total of 40 children, ages 6-12 years old, and three adults were affected by the leak, Durham County officials said. Six children were assessed at the scene as being in serious condition, but their conditions were downgraded at the hospital, officials said.

Three adults were also taken to a nearby hospital — two of them around the time of the leak — while the third was in a nearby building and was taken a few hours later.

Their injuries were described as non-life threatening by Durham police.

The patients were transported to Duke University Hospital and to Duke Regional Hospital.

“Those transported were exhibiting symptoms such as vomiting, respiratory illness, and skin and eye irritation,” police wrote.

Around 35 to 40 children and adults were in the pool at the time of the incident, officials said.

One hundred children were at the YMCA from Club Boulevard Elementary earlier to swim as part of a summer camp.

When they left, a lifeguard noticed a strong chemical odor. Someone started having trouble breathing, so emergency responders rushed to the YMCA.

Meanwhile, the kids who had left the YMCA and were back at school started having problems, too.

Officials say there was a reaction between the sodium hypochlorite, which is used to clean pools, and sulfuric acid which balances the pH of the water.

“Where those two chemicals mixed, there was a leak. And, that got down to the floor and started reacting with one another in a manner (they’re) not supposed to,” said Willie Hall, Durham assistant fire chief.

Fire officials say it was a mechanical issue, potentially either a hole in a tube or a vat that was not properly sealed.

Man streets around the YMCA were closed for several hours Wednesday afternoon and evening. All streets reopened in the area around 8:30 p.m.

Patrons are asked to visit the YMCA’s three other area facilities – American Tobacco Campus, Hope Valley Farms YMCA or the Lakewood YMCA. There is no time line for when the facility will reopen.

There is no time line for when the facility will reopen but officials said they would re-inspect the pool before reopening.

YMCA officials said late Wednesday they will determine by 10 a.m. Thursday if the YMCA will reopen Thursday.