A noble gas-chlorine gas mixture having broad-spectrum effectiveness against bacteria, viruses, mold, fungi, algae including spore forming microorganisms, termites, roaches, mice and other organisms. The noble gas, preferably argon/chlorine gas mixture (Chloragon) is introduced into an enclosed area where the bacteria, virus, mold, fungi, etc., are found and allowed to remain so that the gas composition can penetrate completely into the space including cracks and crevices. After the remediation is complete, the enclosed space should be ventilated or air movement increased to disperse the remaining gas composition.