The term is Intrinsically Safe. It's for equipment that is guaranteed won't be an ignition source, specifically intended for things intended to be operating in confined areas where there's a danger that combustible gases can build up.
To reinforce, this is harder to achieve than it might seem. Sparking in switches and buttons and electrostatic discharge both are kind of invisible in normal environments but can be disaster on an oil rig or in an area of a hospital where pure oxygen is flowing. All the paperwork and monitoring to make sure that the design is correct and that the manufacturing stays within spec costs money too.
That's only for one form of explosion protection. Some methods of protection are for explosion prevention, other forms are mitigation.
Explosion proof / flame proof enclosures don't prevent explosions. Their sole purpose is to contain the explosion and to ensure that the gases escaping from the enclosure do not ignite the surrounding atmosphere. The beauty of a flameproof enclosure is that I can put standard, non-protected electronics into an enclosure and use them in a hazardous area. It's a much more affordable way of deploying electronics into hazardous areas, rather than designing from scratch and certifying.
>Wait, what? The implication is that their other cameras regularly cause explosions?
Non-explosion protected electronics... sure. All you need is an atmosphere of sufficient concentration and a spark with sufficient ignition energy OR a hot surface that is above the atmosphere's auto ignition temperature (think a hot resistor on a PCB). Some chemicals have absurdly low auto ignition temperatures or ignition energies. Engineers must spec equipment for chemicals they expect to encounter within the hazardous area. Engineers also have to factor in how often the flammable atmosphere will be present. All of this is spelled in out IEC60079 for Europe and RoW. US has their own standards.
Some electronics use a spark gap as a form of surge protection:
https://en.wikipedia.org/wiki/Spark_gap#/media/File:PCB_Spar...
None of that would be acceptable in an environment that requires intrinsically safe equipment.
The electronics also need to be carefully current-limited so there's no chance they overheat and cause an explosion that way too.