Comparing costs of carbon monoxide v.s. sodium pentobarbital

From ANIMAL PEOPLE, October 2006:
After claims that gassing is safer for employees, the most
persistent argument for killing animals by carbon monoxide instead of
sodium pentobarbital is that carbon monoxide is less expensive–if
only because most of the gas chambers now in use were installed and
paid for decades ago.
“Switching to lethal injection would mean investing in drugs
and training staff,” reported Raleigh News & Observer staff writer
Marti Maguire in February 2006. “That could strap counties that now
spend as little as $20 per animal. The Orange County shelter spends
$150 per animal,” using lethal injection, Maguire wrote.

Also in February 2006, American SPCA Northeast Region
shelter outreach manager Sandra Monterose told Alicyn Leigh of the
Long Island Press that carbon monoxide, as used in Freeport, was
less expensive than “injection of sodium pentobarbital with the use
of pre-euthanasia anesthetics by a trained professional.”
Friends of the Columbus County Animal Shelter volunteer
veterinarian John Stih, of Whiteville, North Carolina, told Deuce
Niven of the Fayetteville Observer in May 2006 that gassing is more
cost-effective than injection, at $10-$12 per injection.
Columbus County animal control director Rossie Hayes told
Niven that the shelter pays about $130 per month for bottled carbon
monoxide.
Doug Fakkema does not buy the claims. “As an 18-plus year
shelter director, including serving as shelter supervisor at
Multnomah County Animal Control in Portland,” among the larger
shelters in the U.S., “and as a 17-year animal care and
control consultant,” Fakkema told ANIMAL PEOPLE, “I am familiar
with costing out programs. I can say without any hesitation that the
estimate of $150 per dog to euthanize by injection is ridiculous.
“Fatal Plus [the top brand of sodium pentobarbital] costs $0.18 per milliliter. A syringe and needle costs $0.13,
PreMix (ketamine/xylazine) $0.40 per milliliter. With doses
calculated, the cost for euthanizing an 80-pound methadrine-fed pit
bull would be $1.92 for 4.8 milliliters of PreMix, $0.13 for the
syringe and needle, and $1.44 for eight milliliters of Fatal Plus,
for a total of $3.49.
“To suggest that training increases the cost by $146-plus per
animal is absurd,” Fakkema said. “Dare I say the person drawing
those numbers must be drawing them out of a hat? If a shelter does
euthanasia by injection on a thousand dogs per year, then according
to that figure, it must spend $150,000 for euthanasia. You could
hire two full-time vets for that money and equip a mighty fancy
euthanasia room! And you wouldn’t have to spend any training money.
“Yes, it costs money to train staff to perform euthanasia by
injection,” Fakkema acknowledged. “But this is a one-time cost
which is spread out over the number of animals euthanized. The
amount of wages paid doesn’t make a whole lot of difference. My cost
model shows that wage differences impact the cost per animal only a
little.
“The shelter here in Charleston,” Fakkema concluded,
“euthanized by injection 10,000 animals in 2002, at a cost of
$15,300. The cost would have been $1.5 million dollars according to
the $150 per animal estimate. That’s almost their entire budget.”