A fire in a laptop caused a plane to make an emergency landing.

The frightening incident happened on a JetBlue Airways which was forced to land at Gerald R Ford International Airport in Michigan.

It is the latest in several incidents where lithium ion batteries have sparked fires in electronic devices ranging from mobile phones to laptops.

It’s such a concern that a new invention to deal with the problem called AvSax is now on board several major US carriers.

The JetBlue flight was heading from John F Kennedy International Airport in New York to San Francisco International Airport.

In a statement JetBlue said there were “reports of smoke emitting from a carry-on bag holding an electronic device.”

Airport fire crews responded but the fire was out before the plane landed safely and none of the 158 people on board were injured.


How do AvSax work?

The AvSax is a special fire-retardant bag used when lithium-ion batteries in mobile phones or other electronic devices catch fire and has been deployed on planes several times already this year.

Simply pour at least two litres of water into an AvSax and then drop the burning device into the bag. The water activates the polymer gel inside the bag causing it to expand around the device. Should the device keep on venting then the AvSax is tough enough to absorb the force.

In short, the AvSax cools the batteries in the device, reducing the likelihood of the battery catching fire but if it does go into thermal runaway it is all contained within the bag.


Why are AvSax needed?

There are hundreds of potential fire risks among the electronic gadgets people take on board aircraft.

Planes carrying 100 passengers could have around 500 lithium batteries on board when you tot up all the laptops, cameras, e-readers, tablet computers and mobile phones .. and they pose a potential fire danger.

All are powered by rechargeable lithium-ion batteries but there is always a possibility that poor quality or damaged batteries can overheat, causing the device to catch fire.

This is known as thermal runaway, a rapid, uncontrolled chemical reaction within the battery that causes the internal temperature to rise. When one cell in a battery overheats it can produce enough heat - up to 900°C (1652°F) - to cause adjacent cells to overheat. This can cause a lithium battery fire to flare repeatedly.