A thank you from Heaven.
As a self-proclaimed tree hugger, I was mainly concerned about two things: fire and litter. Our lanterns were 100% biodegradable - all paper and cardboard - with fire retardant paper. I will admit that one snagged (briefly) on a treetop, but quickly released and continued its journey.
For safety's sake, make sure there is very little wind and you are in an open area. Similar to fireworks, cities and counties have their own rules and regulations. It's a good idea to double-check.
Our lanterns were purchased from www.theskylantern.com