The present disclosure generally describes an antimicrobial composition comprising: a water solution comprising a chlorite salt and/or chlorine dioxide having a concentration ranging from about 2,000 parts per million to about 8,000 parts per million, and at least one quaternary ammonium salt having a concentration ranging from about 5,000 parts per million to about 10,000 parts per million. The present compositions are advantageously effective against a variety of bacteria, viruses, molds, and fungi, and may be used in a variety applications. Such applications include, without limitation, healthcare setting and equipment disinfection, food surface disinfection, agricultural disinfection, and personal hand care disinfection.