They integrate the general safety notice and are aimed at providing specific information about the nature of possible dangers.
Fire hazard:
To indicate a specific fire hazard.
The cause of fire breaking is described here.
Electric shock hazard:
To indicate a specific electrocution risk.
The cause of electrocution is described here.
Burn hazard:
To indicate a specific burn hazard.
The cause of burn is described here.
Forbidden areas:
To forbid the access, the transit or the stay in a dangerous area.
This area describes the forbidden area: for forbidden areas are meant dangerous places or the approaching to mechanical moving parts.