What constitutes a Class 4 laser?

A Class 4 laser is defined primarily by its potential to cause harm due to its high output power. Specifically, these lasers can indeed inflict damage not just to the eyes but also to the skin. This characteristic is critical because it highlights the safety precautions necessary when working with or around such lasers.

The classification system for lasers is based on their ability to cause damage; Class 4 lasers have the highest risk of causing significant injury. Unlike lower-class lasers, which may only cause harm under specific conditions or exposures, a Class 4 laser poses a significant hazard even with brief exposure.

In contrast, options that mention specific power levels, indirect exposures, or calculations in joules do not appropriately encapsulate the risks associated with Class 4 lasers. This underscores the importance of recognizing the ability of these lasers to directly cause immediate and serious injuries, making the knowledge of their classification vital for ensuring safety in environments where they are used.