Which type of laser would most likely burn skin upon contact?

Class 4 lasers are the most likely to burn skin upon contact due to their higher output power and greater potential for causing harm. These lasers emit energy levels greater than 500 mW, which can produce significant thermal effects. When skin is exposed to a Class 4 laser, the intensity of the beam can cause immediate burns and serious tissue damage, as well as potential ignition of flammable materials. This makes proper safety protocols and protective measures crucial when working with or around Class 4 lasers to minimize the risk of injury.

In contrast, Class 1 lasers are inherently safe under all conditions of normal use and present no risk of injury, while Class 2 lasers emit lower power (up to 1 mW) and rely on the blink reflex to protect against eye damage but pose minimal risk for skin burns. Class 3 lasers are divided into 3R and 3B categories, with 3R posing lower risks and 3B potentially causing eye injury and burns under certain conditions, but they still do not have the same high risk of skin burns as Class 4 lasers do.