PROTECTING WOOD POLES WITH VAPAM (POLE GAS)
A-1. INTRODUCTION.-This appendix covers a
method of treating Douglas fir, western red
cedar, ponderosa and southern pine, and larch
utility poles to arrest and prevent internal wood
decay and to destroy insects such as termites,
carpenter ants, and golden buprestids. 'This
method utilizes an agricultural fumigant, sodium
N-methyldithiocarbamate, known under the trade
name Vapam, also identified as pole gas, that
effectively sterilizes the poles in the section
treated. In addition to rapid sterilization of the
wood, a fungi-toxic residual is deposited in the
cells of the wood from the gas phase. This
residual is effective for an indefinite period since
chemical analysis shows the residue to be
principally elemental sulfur.
A-2. TREATMENT.-Use Vapam fumigant in
wood poles at the time of groundline bore test
inspection and as a supplemental groundline
treatment. Schedule poles known to have
internal decay or that have white wood showing
near groundline for treatment before they have
decayed to the point where replacing them is
A-3. EQUIPMENT AND MATERIALS.-
(1) A 9/16-inch wood auger.
(2) Vapam in 1-pint bottles.
(3) Treated wood filler plugs (5/8 by 6
(4.) Safety goggles.
(1) If the pole is inspected with a sonic pole
tester and no low readings are recorded
and no evidence of wood-destroying
insects is noticed, do not bore that pole
and, hence, do not use the Vapam.
(2) In poles with either decay pockets or in-
sects, bore a hole in each quarter at
groundline and one hole 2 feet above
groundline, preferably above the decay
(3) Inject equal amounts of Vapam into all
the holes, a total of 1 pint per hole or the
amount it will hold (fig. A-1).
(4) Plug holes with treated plugs. Wear
safety goggles to prevent any of the liquid
Vapam from splashing into the eyes.
(5) Dispose of empty Vapam containers.
DO NOT transport the empty containers in
a closed vehicle.
Figure A-1. Applying Vapam treatment.