To be considered for inclusion on this list, plants must go through a very structured process that starts with an initial plant walk-through to assess whether it has the proper equipment and trained personnel to process wood properly.

To complete the qualification process, the plant must then successfully produce a specified number of charges of white wood, followed by proper treatment of said wood, all under the careful eye of our partner, Timber Products Inspection. All of these steps must be completed within a 60-day period.

If a plant successfully qualifies and is on this list, it can be suspended or disqualified from the WQC program if it fails to maintain the same level of performance that it demonstrated during the qualification process.

There is no other published “approved list” of plants associated with the cooperative program. WQC is also the only inspection/quality assurance program associated with the cooperative program that requires such a qualification process.

Approved Plant List


ACZA - Ammoniacal Copper Zinc Arsenate
C - Creosote
CCA - Chromated Copper Arsenate
N - Copper Naphthenate
P - Pentachlorophenol


DF - Douglas Fir
LP - Lodgepole Pine
NP - Northern or Red Pine
PP - Ponderosa Pine
SP - Southern Pine
WC - Western Red Cedar
YC - Alaska Yellow Cedar
WL - Western Larch
Major Product:
TSO - Treating Service Only


Will Cox
1888 Main St., Ste. C #434
Madison, MS 39110