Pressure Treated Lumber. Wood, usually pine or fir, that has been injected with chemical preservatives to guard against rot from exposure to moisture. One of the chemicals used is copper sulfate, a salt, that accounts for the green color. These chemicals are caustic (the poison arsenic used to be a common ingredient) so proper PPE should always be used when handling, cutting, or sanding.
http://www.beaucheminlumber.com/lumber.htm
Pressure treated wood should always be used when there is a possibility of contact with moisture, including direct contact with concrete. In residential construction, sole plates on a slab are PTL, the rest of the wall framing members are standard lumber.
More at http://www.strongtie.com/productuse/PTWoodFAQs.html .
http://www.beaucheminlumber.com/lumber.htm
Pressure treated wood should always be used when there is a possibility of contact with moisture, including direct contact with concrete. In residential construction, sole plates on a slab are PTL, the rest of the wall framing members are standard lumber.
More at http://www.strongtie.com/productuse/PTWoodFAQs.html .