Wet sanding drywall with a sponge is a safe technique of drywall sanding that significantly reduces exposure to high concentrations of dust and respirable silica. It is considered preferable to dry sanding by The National Institute for Occupational Safety and Health (NIOSH).
In a controlled laboratory study conducted by Young-Corbett, wet sanding was found to reduce exposure to dust by as much as 60 percent. Only vacuum dust collection systems were found to reduce exposure more. NIOSH studies indicate that the general avoidance of wet sanding by contractors is not because of safety issues, but rather concerns over drying time and texture of the finish.