Why does this need to be explosion proof?

A world first on our Livestream at the FANUC 2024 Open House.

Grant from Cyan Tec shows us their collaborative robot that is explosion proof.
But why?
Systems like this are needed for applications such as spray painting where the medium in use is flammable. Not only that, the collaborative robot enables operators to work alongside them. This gives flexibility so the robot (cobot) can do the larger batch runs whilst the skilled operator can undertake the one-off and more complex tasks. This also combines with the ease of use of these machines that are extremely easy to program.