[2] As a copper carrier, ammonia has the advantage that it will penetrate difficult-to-treat Western species better than other waterborne preservatives.
[2][4] Formulations of ACQ differ in the "carrier" (complexing agent for copper), either ammonia or ethanolamine; and on the quaternary ammonium cation present.
[2] The ammonia carrier ACQ-B improves its ability to penetrate into wood that is difficult to treat, like some US Western lumber.
The formulations with ethanolamine, especially ACQ-D, are generally used for easier woods (such as southern pine) because it provides a more uniform surface appearance.
The quaternary ammonium cation is added to prevent growth of copper-tolerant bacteria, fungus, and mold,[2] as an insecticide.
[citation needed] Bunks of dried lumber are loaded into a long (up to 150') cylindrical container, seven feet in diameter.
[2] DDA chloride is approved as germicide, fungicide, and algicide for disinfectant products that have been used for decades in hospitals and other commercial and industrial establishments.
[5] One disadvantage of ACQ is that significant amounts of air pollution, in the form of ammonia, are released from treatment plants and freshly treated wood in storage yards.
Chemical Specialties, Inc (CSI, now Viance) received U.S. Environmental Protection Agency’s Presidential Green Chemistry Challenge Award in 2002 for commercial introduction of ACQ.