Why is the use of halon agents strictly controlled?

The use of halon agents is strictly controlled primarily due to their damaging effects on the ozone layer. Halons are extremely effective at suppressing fires, but their chemical properties lead to the release of bromine when they break down in the atmosphere. Bromine is known to be an ozone-depleting substance, which contributes to the thinning of the ozone layer that protects Earth from harmful ultraviolet (UV) radiation. This environmental impact prompted the global community to regulate and eventually phase out the use of halons, as part of the Montreal Protocol aimed at protecting the ozone layer.

While some aspects like mutagenicity and carcinogenicity might be important for other chemicals, the most critical reason for the strict control of halons specifically relates to their contribution to ozone layer depletion. Additionally, concerns about groundwater pollution are less relevant to the nature and control of halon agents compared to their atmospheric impact.