— Officials are determining if the downtown Durham YMCA will reopen Thursday morning after 42 people were taken to area hospitals after a poolside chemical spill on Wednesday afternoon.

According to Jennifer Nelson, Associate Vice President of Communications for the YMCA of the Triangle, a lifeguard noticed a strong chemical odor near the indoor pool pump room Wednesday afternoon.The YMCA immediately contacted EMS, who contacted the Durham Fire Department, which declared a hazmat situation at about 2:45 p.m.

“We ended up with 11 units from the Durham Fire Department on the scene, about 25 of our firefighters, including the hazmat team,” said Daniel Curia with the City of Durham Fire Department.

Authorities said the chemical was sodium hypochlorite, not chlorine as the Durham Fire Department initially stated. Sodium hypochlorite is a chemical used for everyday upkeep of swimming pools, authorities said.

According to Nelson, about 100 campers swam in the pool as part of their daily routine Wednesday before being taken back to their camp at Club Boulevard Elementary School.

At about 3 p.m., some children began complaining of breathing issues and staff members contacted EMS and parents, Nelson said.

“Everybody came out coughing, choking, spitting up and then they told everybody to get out of the pool and then once everybody was out they were choking and spitting up,” said 9-year-old camper Kamali Siler.

According to Wil Glenn with the City of Durham, 40 children between the ages of 6 and 12 and two adults were taken to either Duke Hospital or Duke Regional Hospital.

Six children were deemed to be in serious condition by EMS workers at the scene, but their conditions improved at area hospitals, authorities said. Most children were released from the hospital by Thursday morning.

"It's really scary because that is my only child," said parent Raquel Adams.

By Wednesday night, nearly all the children had been treated and released, officials said. One person from a building adjacent to the YMCA was also treated at a local hospital.

Siler said that children began feeling sick while at the pool, but they were not put on ambulances until they arrived back at the school. Every child was given a colored wristband to indicate to counselors how severe their symptoms were, she said.

"I felt lightheaded with my throat hurting," Siler said of her symptoms before she was taken to the hospital via ambulance. "I fell really good now. We had popsicles and played games while we waited for our parents [in the hospital]."

According to WRAL's Dr. Allen Mask, side effects of exposure to the chemical include blurry vision and watery eyes as well as coughing, wheezing, skin irritation, nausea and vomiting.

Glenn said those taken from the YMCA to area hospitals were exhibiting symptoms that included vomiting, respiratory illness and skin and eye irritation.

"There were no kind of chemical burns or nothing like that. It was all mainly coughing and one or two maybe vomiting," said Siler's father, Adul Siler.

Abdul said his daughter was discharged for the hospital with only a prescription for Flonase, for sinus irritation.

Long term exposure to sodium hypochlorite could result in chronic conjunctivitis and pulmonary edema- a build up of fluid in the lungs, Mask said.

Fire officials said that the spill occurred as a result of a mechanical issue that caused the sodium hypochlorite to mix with another chemical in a way that was not intended. They said the symptoms were caused largely by fumes from the chemical mixture as opposed to exposure to the chemical in the water.

“Some sort of mechanical issue, whether it’s a pinhole in the tubing or the piping that goes to the chemicals or maybe one of the seals on tops of the vats was not properly sealed, But, it appears it leaked out and caused that issue,” said Willie Hall with the Durham Fire Department.

Parents said that the camp was a seven week program and is scheduled to end Friday. While most parents said their children would attend the final two days of the program, many agreed that swimming would not be allowed.

"He won't be getting in the pool no time soon with them," Adams said of her son.

Most parents said they they believed the situation was well handled by the YMCA and hospital staff.

According to the City of Durham, multiple roads were closed during the incident, but all had reopened before 9 p.m.

"I went to pick up my other daughter from Club Boulevard and they shut down the whole street to let the ambulances in," Abdul Siler said.

Authorities said hazmat crews needed to enter the building three times in order to secure it.

A spokesperson for the YMCA said the situation would be reassessed Thursday morning to determine when it will be safe to reopen the building. Many people spent hours Wednesday waiting outside to retrieve personal belongings, including car and house keys, that were stored in lockers inside the facility.

“They told us to vacate the building. They didn’t tell us what was going on or anything. We found out after we got out of the building that there was a chemical leak,” Warren Poole, who was evacuated from the facility.

The Downtown Durham YMCA was last inspected on Jan. 4 2016 and four points were deducted from its public health inspection, but it was uncelar why those points were deducted.