Class 4 lasers include all lasers with beam power greater than class 3B. By definition, a class-4 laser can burn the skin, in addition to potentially devastating and permanent eye damage as a result of direct or diffuse beam viewing. These lasers may ignite combustible materials, and thus may represent a fire risk. Class 4 lasers must be equipped with a key switch and a safety interlock. Many industrial, scientific, military, and medical lasers are in this category.

According to the revised ANSI Z136.1 Safe Use of Lasers, laser area warning signs should be posted around Class 3 laser areas and is required to be posted around all Class 3B and 4 laser areas. Additionally, NOTICE signs are required for Class 3B and Class 4 lasers during maintenance, servicing, and similar situations.

LIA has a laser area warning sign for any type of laser. LIA signs are 10" x 14" in size are are available in plastic material. All signs meet the ANSI Z136.1 requirement for laser safety and can be customized with your laser's specifications and warning statements for only $5.00 per sign.