Pressure-treated wood is a type of wood that has been filled with chemical preservatives to prevent it from insects and rot. The wood is put in a depressurized tank to remove the air and replace it with a preservative. This pressure treatment is the best way to prevent insects and rot. However, it does not prevent corrosion and weathering.  Pressure-treated wood perfectly suits outdoor activities. Sawdust from the wood is irritating when used for indoor projects. Always wear gloves, a dust mask, and eyewear when handling pressure-treated wood. Never burn this wood. Dispose of scraps in a landfill.