What are the four colors of safety signs and what do they mean?[^1^]内容如下：

According to the American National Standards Institute (ANSI), there are four colors of safety signs and they mean the following[^1^] [^2^] [^3^] [^4^] [^5^]:

- **Red** indicates danger or immediate risk. It is used for fire safety, prohibition, and stop signs.
- **Orange** indicates a machine- or equipment-related hazard. It is used for warning signs and labels.
- **Yellow** indicates caution or minor risk. It is used for slip-and-fall, trip-and-fall, and other potential hazards.
- **Green** indicates an emergency exit or egress. It is used for fire exits, first aid, and safety instructions.

There is also a fifth color, **blue**, that indicates directions or safety information. It is used for notices, instructions, and information signs. However, blue should not be used for fire exit routes, which should be green.