Some of my friends said gas released from boiling chlorinated tap water is chlorine and it's toxic if we breathe it. But, I have doubt on this claim because I thought it requires electrolysis to extract chlorine gas from such water. Though, I do recall smelling the distinct smell from chlorinated water like in the swimming pool. Is that the smell of chlorine or some derivatives of chlorinated compound?

Does anyone know is it true that chlorine gas can be released from water by simply boiling chlorinated water? If so, what would be its extend? Should we be worried at all?

I searched google, but I don't find the results credible enough for me to believe.

Thanks

Perhaps if there is a reduction agent present. The only thing strong enough to steal an electron from chlorine is fluorine.