The main safety concern in working with lasers is never to look directly into the beam. Some sources recommend avoiding reflections of the beam from shiny surfaces, as well. As an example, a 2mW laser (such as the laser pointer) entering the eye carries 2mW into it. Sunlight has an intensity of about 1000W/m² on a sunny day. If the pupil has a diameter of 2-4mm and hence an area of 3-12 mm², then sunlight carries 3-12 mW into the eye of someone staring right at the sun. However, in addition all of the light from a laser is at one frequency, often one which can be damaging to the eyes, so I usually said that looking at the laser pointer is roughly equivalent to staring at the sun with open eyes. I was careful to stress to my audiences several times never to look directly into the beam or shine it in anyone's eyes.