The Centers for Disease Control and Prevention issued a warning about the chemicals used to keep pool water clean, saying they poison thousands of people, many of them children, every year.
William Koenig is one of the victims. He was five years old in April 2007 and was staying with his family at a hotel near Portland's airport.
As reported on KATU News at the time, Koenig felt sick after swimming at the hotel pool. He said he became nauseous and got a bad headache.
"My tummy hurted," he told the KATU reporter. "I got out of the pool, go to the house, take a little rest."
But the next group that went into the pool suffered much more. The fire department said 13 children from a wedding party ended up in the hospital.
"They just started covering their mouths, coughing and crying, and that's when we pulled them out," said Daphne Kalamafoni, an aunt to some of the children.
The fire department said a hotel worker mixed two pool chemicals that should not be mixed and created a toxic cloud.
"I don't want to get chemicals in my mouth anymore," said Koenig at the time.
The KATU Problem Solvers tracked Koenig down seven years later and found him living with his family near La Center.
He said he does not have lasting effects from the poisoning, but he is still wary of pools and pool chemicals.
"Don't just experiment. Know what to do," said Koenig.
The latest study from the CDC showed about 5,000 people ended up in the emergency room in 2012 because of pool chemicals. The study said some breathed in toxic chemicals, others got burns in their eyes or on their skin, and nearly half were children.
"When you go to a pool, it's kind of hard to tell which ones are good and which ones are bad," said Koenig's mother, Julie.
Oregon counties inspect public pools once or twice a year.
Some county tests show chlorine levels far higher than the health department's safety limit.
County tests results for Sheraton Portland Airport last year showed chlorine levels at 50 parts per million, ten times more than the required limit.
Tests found the same results last year for the Rodeway Inn on Northeast 181st, the Astoria Apartments on Northeast 73rd and the Portland Marriott Downtown Waterfront.
"I travel with a bottle of test strips," said Ron Allen, who works for a pool chemical company called SCP.
He said he runs his own water tests when he goes to public pools with his family.
Most families do not carry test strips to the pool. So, how can you tell if there are chemical problems at the pool where you and your kids are going?
First, the smell: does it smell strongly of chlorine? If so, that's a problem.
"When I go to a pool, I smell it to see if it smells like normal," said Koenig.
Next, the feel: does it feel slimy? Does it irritate your skin, or make it tingle or itch?
"Sometimes I go into it and I feel the water before I actually dive in," added Koenig.
Also, is the water burning your eyes, nose or mouth? Are you sick to your stomach, do you feel dizzy, or have a headache?
These are all signs the chemical balance could be off and you need to get out of the pool and talk to the pool manager.
The CDC said the approximately 5,000 cases in 2012 included children poisoned at home pools as well as public.
Allen said one problem is that some pool chemicals may not look poisonous to children. For example, chlorine granules may look like a familiar food or household product.
"That's the danger," said Allen. "It looks like sugar; it looks like detergent."
He said blue liquid chlorine may look like snow cone syrup, or a play item.
"This looks like something you could blow bubbles with," Allen said, as he lifted up a bottle.
Allen said you should lock up your pool chemicals so pets and children can't access the poison.
"We all know that little kids like to put things in their mouths." said Allen. "Chlorine doesn't taste good, but it's not going to keep them from putting it in their mouth the first time."
The final factor in those 5,000 trips to the emergency room is how you use and mix chemicals at your pool.
Allen said some of the chemicals are so reactive that just opening the bottle can make you sick. He recommends opening the containers in an open space.
"Pop that lid off and you're in a garage, it'll, poof, almost knock you out," said Allen.
He also recommends storing chemicals separately -- liquids away from dry chemicals -- because the two can react. He said you should never store liquids on a shelf over dry chemicals because even one drop of liquid landing on a dry chemical can start a fire.
"It can be a really big fire, take out a house, a warehouse, an apartment complex," said Allen.
Also, he advised, wear gloves and safety glasses and use a dedicated scoop to add the chemical to a bucket of water. Never add the water to the chemical, because the chemical can splash up and burn your face.
"Not only do we need to be safe in the swimming pool, we need to be safe with ourselves, we need to be safe with our house or our garage or wherever we keep our chemicals," added Allen.
Seven years after the poisoning, William Koenig and his family ask more questions.
"Talk with my friends who have pools and talk about what chemicals they're using and how," said Julie Koenig.
Allen and other people who work with pool chemicals and safety encourage people to take full showers before going into pools. They said chlorine reacts with the oils, soaps and other things on your body and changes the chemical balance of the pool, potentially making the water more dangerous for you. If you smell chlorine at a pool, that is not actually chlorine, they said, but the substance formed by the chlorine reaction with your body oils and fluids, and is a sign that there may not be enough chlorine in the pool to sanitize it.
KATU has compiled new information on the latest pool inspection reports for Multnomah County.
Do you own a pool? Here are more tips on how to handle the chemicals to keep yourself and your family safe.
- What if there is a pool chemical emergency? Here's what to do.
Tips for adding chemicals to pool water: