It is formed when ammonia is added to water containing free chlorine.

Many municipalities have moved from free chlorine to chloramine as a disinfection agent.

Such mixtures release either free chlorine or ammonia, both of which are harmful to breathe.

So Doctors Without Borders organized the distribution of free chlorine.

It is supposed to consist of chlorine tetroxide with some free chlorine.

It is resistant to all practical levels of chlorination, surviving for 24hrs at 1000 mg/L free chlorine.

In swimming pools, chloramines are formed by the reaction of free chlorine with organic substances.

Pool test kits designed for use by homeowners are sensitive to both free chlorine and chloramines, which can be misleading.

Residual free chlorine can then be removed by exposure to bright sunlight for about 4 hours.

Then an equilibrium ensues, with a small percentage of the chlorine "free".