Re: Can chlorine in drinking water become chlorine gas?

Most definitely yes.  If you can smell, it is in gaseous or vapor form and 
is entering your body.  Your body also absorbs it through the skin.  You 
also drink it in tap water.  Though usually added to the water supply as 
sodium hypochlorite, this product breaks down into chlorine or byproducts 
of disinfection, including more toxic dichloramines and monochloramines to 
name a few.  Talk to your municipality about switching to ozone, but they 
may laugh at you due to the expense.  The smaller amounts of chlorine you 
ingest on a normal, daily basis do not present acute hazards, but chronic 
effects may be caused by disinfection byproducts.  Because of the myriad 
of little critters in water worldwide, the alternative of not chlorinating 
your water has far worse implications.