Checked the reviews for this particular one, no one is mentioning fire. If you search for Apple charger caught fire you will find some, can happen to any electronic device.

I have three of them plugged in 24/7 for 3 years now and recommended them to others, all houses still standing. But you can also get the original 96 W charger from Apple, it's bigger so it can dissipate heat better than the smaller ones.