What is the primary risk associated with Class 4 lasers?

The primary risk associated with Class 4 lasers is eye and skin exposure that can cause serious injury. Class 4 lasers are the highest classification of lasers and are capable of causing immediate harm to human tissues upon exposure. The energy emitted by these lasers is intense enough to lead to permanent eye damage and severe skin burns.

Due to their high power levels, these lasers can also pose additional hazards, including the potential for creating fires if there are flammable materials nearby. However, while fire hazards are a significant risk, they are secondary to the immediate and potentially life-altering injuries that can occur from direct exposure to the beam.

Electrical shock is primarily a concern with the equipment and power sources used to operate lasers rather than the lasers themselves. Similarly, environmental contamination is not a direct consequence of laser exposure but can relate to the use of certain chemicals or materials in laser operations. Thus, the most pressing concern with Class 4 lasers is the direct harm they can inflict on eye and skin tissues, which is why this choice is the most accurate.