Steam explosions are considered industrial disasters in many industries, including the metal and paper industries. Steam explosions are initiated by the collapse of vapor film, which separates hot molten material and water. We have proposed the countermeasure by adding polyethylene oxide (PEO) into the water to stabilize the vapor film. A molten tin jet was immersed in these PEO aqueous solutions for a wide range of molecular weight (400 − 8000 kg/mol) and concentration of PEO (up to 0.1 wt%) to identify the occurrence of steam explosion. The steam explosion was suppressed for higher molecular weight and denser concentrations of PEO. The measured cloud-point temperature and solid-sphere quenching temperature indicate that steam explosion can be suppressed when the cloud-point temperature is a few Kelvins below the saturation temperature so that the solute PEO is deposited near the vapor-liquid interface to increase the viscosity more than two thousand times higher than that of water to stabilize the vapor film as a steam explosion retardant. For the lower molecular weight of PEO, the cloud-point temperature is close to the saturation temperature, PEO concentration must be thicker to precipitate the PEO to stabilize the vapor film.