CHARLOTTE, NC -- On Wednesday afternoon, 43 people -- mostly children -- were rushed to the hospital after a chemical leak at the downtown Durham YMCA.

Officials believe it was a pump failure that created poisonous fumes.

“It appears to be some type of mechanical issue,” fire officials said. “Whether it's a pinhole in the tubing or piping that goes to the chemicals or maybe one of the seals on top that was not properly sealed.”

Investigators are still looking to determine exactly how those pool cleaning chemicals leaked. The seeped sodium hypochlorite reportedly mixed with other chemicals, creating poisonous fumes.

YMCA executives say about 100 campers were swimming at the time.

When some started complaining of respiratory issues and nausea, the leak was uncovered, the facility was evacuated, and dozens were rushed to the hospital.

North Carolina does require pumps to be functional and up-kept.

Mecklenburg County inspections examine pumps and chemical feeders to make sure they’re in "good working order," "operating properly," and "in good repair."

But NBC Charlotte pulled public records and found out the downtown Durham YMCA where the leak happened hasn’t been inspected since January 2016, according to online records.

Thankfully that doesn’t seem to be the case at any of the YMCA locations in Mecklenburg county, all of which have been recently inspected.

The Lake Norman location was knocked for having chlorine levels at 50 ppm when recommended levels are 1-3ppm.

But the inspection states that was fixed right away.

If you want to check inspection records yourself before heading to a public pool, you can do so HERE.