Hi everyone, I have short question to those who know better than me: Is the light coming out of a laser engraver enclosure safe?
What I mean exactly: There are ports for air to come in that can be opened up on the sides of the enclosure, where then blue light comes out from the diode laser. But it is by no means direct. Would that blue light still be dangerous? It sort of just illuminates the room, but at this point I’m unsure. Thanks for the help!
In general, no.
The reflected light will not be a coherent beam, so glancing at another reflection from the rest of the room won’t do any damage to your retinas.
However, it’s monochromatic and relatively high-powered compared to most light sources. Staring at the cutting area or a specular reflection from a shiny object is Bad Practice™.
As a rule of thumb, “accidents” have two causes: somebody sets up the conditions and somebody else triggers them. You should always have three layers of defense, so any two can fail: protective shield, baffles, goggles.
You can do without any two of those three in normal circumstances. What you’re guarding against is the unexpected event punching through that last remaining barrier: your tiny niece unexpectedly bouncing into the room and watching the pretty blue light moving around the platform at eye level.
Thanks for the extensive answer!
You can walk with a wooden leg and chew with ceramic teeth, but cannot see with a glass eye. Safety first, for sure.
Maybe one thing to add: the maximum tolerated energy of a laser beam is considered to be 1mW. Current lasers have up to (and more than) 40W. That’s 40,000 mW. So even it is reflected, bounced and diffused at some stages, I, personally, would never trust it gets to 1/40000 within a reasonable distance at all locations.
To have a better understanding: If you take this graph, and continue the scale, the 40W mark would be a few METERS further to the right… 
Thank you for all the great answers guys! I’ve made sure that actually no light escapes the enclosure. I have another question though. I have a TwoTrees enclosure with a seethrough amber viewing layer. My question is, is it safe to look at the laser through that? I mean I can still see some blue colored light through the amber shield, but obviously it’s very weak. So is it safe? So far I assumed so, hope I’m not going blind. 
How do you vent it? If you have ventilation, it must breath somewhere.
Ye okay fair enough, but I padded even that Besides, some light does escape around the bottom of the enclosure. Apart from that, it’s light sealed.
I am pretty sure that blue light would not be safe. My box windows are red, not amber or green.
