There are disclosed various processes, apparatuses and systems for treating a halogen-containing gas such as F.sub.2 that involve generating a plasma in order to reduce chemically the halogen-containing gas into products that are more environmentally manageable. According to a particular embodiment, a reducing agent is mixed with the halogen-containing gas to produce a feed gas mixture and a non-thermal plasma is generated in the feed gas mixture in the presence of liquid water.