Does a gas fireplace with flames need a chimney?

[hatelore]

I was going to add a home improvement tip about saving money on primer loads for nail guns by using just straight 22 caliber bullets, but that might get me a ban when a p99 user ends up in the news.

But def don't install a chimney, they tend to leak water over time. Much cheaper to just buy a 10 dollar c02 detector. Plus if you are lucky most fire departments offer them to the public for free. Double win right there on money savings.