Treating computer room fire risks

Following the Montreal Protocol agreement in the 1980’s, manufacture of the chlorofluorocarbon (CFC) extinguishant gases commonly known under the trade names “Halon” and "Freon" ceased before 1994. 

Although CFCs are highly effective extinguishants that work at relatively low concentrations (8%) with low toxicity and no nasty residues, they are potent greenhouse gases. In the upper atmosphere, CFCs are broken down by sunlight slowly (over decades), releasing reactive free chlorine which destroys ozone, subjecting the earth’s surface to increasing amounts of harmful UV radiation.

See https://en.wikipedia.org/wiki/Bromochlorodifluoromethane and  http://www.bcairquality.ca/101/ozone-depletion-causes.htmland http://www.enviropedia.org.uk/Ozone_Depletion/ODCs.php (among others).

For a while, Halon made before 1994 was recycled from old stocks for specific applications by organizations that could afford it. Everything possible should be done to avoid releasing the gas unnecessarily – especially accidental triggering or inept servicing/installation/testing of suppression equipment.