How far is far enough for the human eye?

Wondering where I could find some information about eye safety and distance in relation to output power and wavelength. I am sure there are many factors that are involved with this type of calculation but there should be some general rules available.

I am posting in the green laser section because this is what I am primarily interested in. I have a new 1800mw 532 I have plans to make some great outdoor photos with in a local canyon and mountain top (using some bounce mirrors and burst optics). Although this is a remote area I am still concerned with safety for my help and anybody else who might be around we were unaware of....especially at a distance of a mile or greater.

Obviously we won't be pointing at aircraft or knowingly at people or wildlife but I still feel responsible to know the risks involved before I get started.

Until know the most green I have worked with is just under 400mw.

I tried searching but couldn't find specific information like this.

Anyone with a link?

Thanks,
Jeff

Here's the calculations: Laser safety - Nominal Ocular Hazard Distance and Area

If you have an iphone you can use this app: L V R Limited : Laser Hazard Distance App

This document has a TON of info on the subject:
http://www.lumetrics.com/documents/ATT00230.pdf

Heard good things about this, haven't used it yet: (demo only calculates for 532nm) LaserSafe PC Demo Page

Exactly what I was hoping for! Thanks guys! I am already feeling a bit better about what we are planning.
Cheers!
Jeff

There's also Scangard Lite free download version
Laser Visuals - Scanguard laser show analysis software : Lite Version