I have a lot of open space in my grow room so can make sure there are no flammable things near it or especially above it. I also keep it in front of and below my 12" oscillating fan so the CO2 and heat are spread into the room and blown into the plants. Could be harder to do in a crowded tent tho.
I mainly only do it during the stretch period when the plants go thru a big growth spurt and can really use the CO2. I also turn up the heat to run around 85 - 90F and add extra light so all systems are redlined. After the stretch I go back to a normal temp of 75 - 80 and only use the CO2 if I don't have enough lights going to heat the room enough to cycle the exhaust fan to pull in fresh air from the greater area of the basement thru the filters.
I have a smoke detector in the room but want to get one of those fire suppression bomb units that will go off if excess heat triggers them. 18 years growing in there and nothing serious has happened yet, knock wood.