A concerned parent has revealed how floating balloons can cause disaster at children's birthday parties.
And it's not because balloons are a choking hazard for very young children - it's because some decorators fill them with hydrogen because helium is "too expensive", the Daily Mail reports.
Hydrogen is just a quarter of the price of helium, seeming like a budget-conscious option for decorators looking to keep costs low for customers.
But as it's an extremely volatile gas, many in the industry consider it's not a safe alternative. The friction caused by kids playing with hydrogen-filled balloons is enough for them to explode.
One mum named Tina found out about this the hard way - when a giant balloon exploded and "shook her house". Her family had been playing with the balloon after her son's seventh birthday party moments before it exploded, she said.
"They tossed the balloon like a beach ball and we even joined in a couple of times. My son took it with him to the bedroom because he wanted to pee and suddenly we heard a loud explosion and the force rocked our house," she said in a post published by Tiny Hearts Education.
Her son suffered a burn on his forearm when the balloon went off.
"We rushed to check on him and bits of balloon skins were everywhere. Some got stuck on the ceiling and some melted on the floor tiles. Miraculously they missed my son's eyes and face," she said.
And when she and her husband contacted the seller of the balloon, they were told a warning sticker noting they were filled with hydrogen had been left off the balloons.
She urged parents to ask for helium when ordering balloons. "This is too dangerous and not many people know this. Like me, they would assume it's helium. Balloons are usually near cakes and lighted candles.
"Hydrogen can react with oxygen along with friction to create energy. The big balloon contained tiny balloons inside which was a recipe for disaster."
Simply hitting the balloon back and forth had created enough friction for the balloon to explode.
"No need for a spark or flame. It's a ticking time bomb if enough friction is made."
Her post was received with shock from other parents as they thanked her for sharing.
"You would never know this unless you were told or worked with the items. Hope everyone is ok. What a fright it would have been," one commented.
Meanwhile, some questioned whether the practice of filling balloons with hydrogen should even be legal.
"That is so dangerous! What was to happen if one of these filled balloons was at a party near the birthday cake and when lit with children all around this balloon exploded spraying the balloon pieces all over the children," another added.