Pressure treated wood is wood that manufacturers pump with chemicals that will help preserve it. These chemicals help prevent wood rot, mold growth and attack from pests such as termites and other insects. Most types of wood can be pressure treated. The lumber is sealed into a vacuum. The air is sucked out of the vacuum and the chemicals are added to the room. When the pressure returns to normal the chemicals are sucked into the wood.
One of the most important steps in restoring old pressure treated wood is sanding the old layer of wood off to expose a new, smooth layer that is free from nicks and scratches. While you can sand pressure treated wood like any other wood, you have to take some precautions to ensure that you don't irritate your eyes or lungs. Because the wood contains certain chemicals always wear gloves, goggles and a dust mask to prevent the inhalation of and irritation from chemicals in the wood.
Keeping pressure treated wood clean will help it look better and last longer. Though the pressure treatment does help prevent wood rot and mold, it does not always keep it at bay. Clean the wood often to help ensure that these contaminants don't damage the wood. Clean the wood as you would any other type of wood. Use full-strength white vinegar, a diluted bleach mixture or liquid soap to remove stains with a scrub brush. Rinse clean with water.
Some types of chemicals that manufacturers pump into pressure treated wood contain arsenic. Though we are often in contact with, and even sometimes eat, organic arsenic, it is the inorganic arsenic that is worrisome for those restoring and using pressure treated wood. The arsenic might leach into the soil and could leach into fruit and vegetables. The arsenic, however, tends to concentrate in areas of the fruit that we don't eat, such as thick peels, seeds or stems.