What is ACQ Lumber?

In the past treated lumber was preserved with a chemical called Chromated Copper Arsenate (CCA). Due to the high concentration of Arsenic in CCA Lumber, the EPA has determined that treated lumber manufactured after December 30, 2003, cannot be treated with CCA.

Alkaline Copper Quarternary (ACQ) is a non-arsenic wood preservative that has answered the EPA’s mandate. It is an effective wood preserver, but highly corrosive on standard non-galvanized (bright), electro-galvanized (E.G.), and traditional zinc galvanized fasteners.

It is for this reason that ONLY HOT DIP GALVANIZED or STAINLESS STEEL fasteners should be used in ACQ Lumber.