Firefighters might face a higher risk of brain cancers caused by exposure to chemicals in fire extinguishers, a new small-scale study says. Veteran firefighters appear to have a higher risk of brain tumors called gliomas, which can be caused by gene mutations linked to flame retardant chemicals called haloalkanes, researchers reported in a study published Monday in the journal Cancer . Advertisement Previous studies have highlighted a mutational pattern, or "signature" in gliomas linked to