Air passengers seriously grossed out after discovering what ‘blue ice’ on planes actually is

New fear unlocked: imagine getting hit by a giant chunk of blue ice falling from the sky.

There are many weird and wonderful things about flying, and blue ice is just one of them.

Everybody knows that toilets on planes aren't the most luxurious of things, but it's better than having to cross your legs for hours at a time.

Over the years there have been multiple instances of the infamous blue ice falling from a plane and hitting the ground.

So what exactly is it and why does it happen?

Even though it sounds like a flavour of vape, blue ice is the frozen blocks of toilet waste stored on an aircraft which sometimes fall to the ground.

Plane toilets aren't the most glamorous of places, but where does the waste go? (Getty Stock Image)

The distinctive blue colour comes from the disinfectant in the toilet system, which freezes at cruising altitude.

Nowadays, most aircraft waste systems are completely sealed and are regularly inspected.

However, all it takes is a small leak from a crack or a faulty seal for the block to form.

The ice breaks free from the plane and has damaged property and caused injuries on the ground.

Back in December 2015, a giant chunk of toilet ice narrowly missed killing a 60-year-old woman in a village in India.

The woman, called Rajrani Gaud, was left with an injured shoulder.

Her neighbours say she was lucky, as the ice collided with a terrace first, which slowed it down before it hit her.

In 2016, a teacher said her mother's house was damaged by falling excrement.

Several people have reported damage to themselves or their property from the frozen waste (Getty Stock Images)

The mother and daughter were woken by a loud crashing noise, only to find a huge hole in the ceiling.

There was also a puddle of water on the floor.

A roofer came round and called it the 'strangest thing they had ever seen,' and that it could be 'blue ice.'

Back in 2012 two neighbours also had damage to their properties in Long Island.

Lois Farella and Anne Grace spoke to the media about the incident, which left a giant hole in the ceiling of their homes.

Ms Grace told CBS: "It's a very huge hole. It did a lot of damage through heavy wood. I can't imagine if it hit a person,"

Ms Farella recalled: "We both woke up to a very loud bang. I looked around - no breeze, no rain, nothing."

Apparently about 25 instances are recorded each year. (Nicolas Economou/NurPhoto via Getty Images)

In September 2014, a furious homeowner claimed low-flying planes on a Heathrow flight path are damaging his £3 million Georgian mansion.

One notable incident took place back in the seventies, when a huge chunk of blue ice crash-landed in a church in the middle of a quiet service.

That's one way to get people's attention!

According to the UK Civil Aviation Authority (CAA), it receives around 25 reports of blue ice hitting something or someone per year.

The key thing is for maintenance on airplanes to prevent the falls from happening.

Apparently in the majority of cases the ice lands in a remote place, or falls to the ground without hitting any people or property, but many have had a lucky escape.