In English, one might say
He smokes like a chimney.
Given the incredibly creative German insults that I've come across (see this German.SE question), I'd like to know what (derogatory) terms/expressions are used for smokers.
"Er raucht wie ein Kamin" - I haven't encountered that one yet.
with "Schlot" being a high, tall thin chimney of a factory or coal power plant, but not the regular chimney through which Santa Claus enters.
Another for someone who smokes lots would be
Kettenraucher (=chain smoker)
I never heard anybody saying these expressions, but a male smoker I personally call
Luftbekacker (air shitter, someone who shits in the air).
And a female smoker I call
Tabakschlampe (tobacco slut).
The female version of Luftbekacker is Luftbekackerin.
Accordingly instead of rauchen (to smoke) I say die Luft bekacken (to shit in the air).
As another alternative: The Cigarette Smoking Man character from the X Files was sometimes derogatively referred to as Cancer Man1. In the German dubbing, this was (in my opinion, fittingly) translated as Krebskandidat.
1: He was so high up in the ranks of a secret agency that even his name was secret and unknown to the protagonists for much of the series. As he usually was rather on the antagonistic side, quite some characters had reasons to hold a grudge against him and refer to him in not-too-polite a manner.