Efficacy of Grignard Pure to Inactivate Airborne Phage MS2, a Common SARS-CoV-2 Surrogate

[Image: see text] Grignard Pure (GP) is a unique and proprietary blend of triethylene glycol (TEG) and inert ingredients designed for continuous antimicrobial treatment of air. TEG has been designated as a ″Safer Chemical” by the US EPA. GP has already received approval from the US EPA under its Section 18 Public Health Emergency Exemption program for use in seven states. This study characterizes the efficacy of GP for inactivating MS2 bacteriophage—a nonenveloped virus widely used as a surrogate for SARS-CoV-2. Experiments measured the decrease in airborne viable MS2 concentration in the presence of different concentrations of GP from 60 to 90 min, accounting for both natural die-off and settling of MS2. Experiments were conducted both by introducing GP aerosol into air containing MS2 and by introducing airborne MS2 into air containing GP aerosol. GP is consistently able to rapidly reduce viable MS2 bacteriophage concentration by 2–3 logs at GP concentrations of 0.04–0.5 mg/m(3) (corresponding to TEG concentrations of 0.025 to 0.287 mg/m(3)). Related GP efficacy experiments by the US EPA, as well as GP (TEG) safety and toxicology, are also discussed.