I had good circulation and my apartment never caught fire for the 3 months I had it running. Call it luck if you want to. I had a successful learning experience with no expenses because if you put weed in terms of money, I broke even and still have all my supplies. If you're careful in your design, this is no more hazardous than cabinet or rubbermaid growboxes, but to each his own. If you don't like it, don't copy it. I've already proven it can be done.
By the way I've been smoking away lately and loving it. I left probably 1/4 of my harvest where I was living before with my friends just because I wanted some feedback from everyone. And I smoked a bunch too before I ever weighed it. I still have 15 grams left and it's about half of what I started with (visually). I think I harvested too soon for the couch lock effect, but I'm very pleased with it. The buds dried and hardened like rocks, the high is strong, energetic and makes you laugh a lot haha. Overall I'm a happy camper. Thanks to everyone who helped me out!