Every year hundreds of stray dogs and cats in Pennsylvania are tossed into metal boxes and gassed.
It can take as long as 40 minutes for them to die.
We don't know how many animals die this way or who is doing the gassing because the Federated Humane Societies of Pennsylvania – the umbrella group representing the three remaining shelters in the western part of the state that use carbon monoxide to euthanize animals - won't reveal the names of the shelters fearing retribution by activists.
In recent years some 20 states have outlawed the use of gas chambers (according to the Animal Law Coalition), among them some of the least progressive states: West Virginia, Georgia and last week, Alabama. Yes, Alabama.
But not Pennsylvania.
The state legislature - which has not passed a companion animal-friendly bill since the dog law revisions of 2008 - can't even move a bill banning gas chambers to the floor of the Senate or the House for a vote.
Last year a bill sponsored by Sen. Sean Logan - who did not seek re-election -passed out of committee and was sent to the Senate floor where it lingered on the calendar for weeks and then mysteriously died. The federated's president Anne Irwin, said her group had no issue with it. Even the ag community was ok with the bill's language after a clause was added to allow poultry farmers to gas their chickens in the event of a disease outbreak.
Now we may have a idea who killed it – and which group continues to block its movement today.
Sen. Andrew Dinniman (D., Chester) has picked up the gas chamber's bill sponsorship this session and said earlier this week that he can't understand why the Pennsylvania Veterinary Medical Association is standing in the way of this legislation.
"We are getting trouble from the PVMA," said Dinniman, a poodle owner. "The irony is that in their clinics vets treat animals like the way people want to be treated at the end of life, with dignity. You're there in the vet's office with the dog at the end. The vets market this approach to pets and charge high fees. It's ironic that the state association would then treat them as a commodity."
The Association of Shelter Veterinarians and the Humane Society Veterinary Medical Assocation have declared carbon monoxide an inhumane method of euthanasia. The widely-agreed upon humane method is by injection with sodium phenobarbital, which is painless.

The American Veterinary Medical Association, in a 2007 study, detailed the horrific physiological effects of using carbon monoxide as a form of euthanasia:

...distress vocalization (this means barking, crying, howling), struggling, attempts to escape, defensive or redirected aggression, salivation, urination, defecation, evacuation of anal sacs, pupillary dilatation, tachycardia, sweating, and reflex skeletal muscle contractions causing shivering, tremors, or other muscular spasms.

There is no question shelter workers have documented the piercing cries, howling, frantic calls, scratching and panic of animals as they are gassed. Just putting them in the chamber is frightening for animals. The chamber is hot, confining and often smells probably like death. They don't know what is happening and they immediately experience panic and distress. The buildup of gas in an animal's lungs is slower if there is decreased ventilation, a leaky valve or seal, or more than one animal in the chamber. There may be no way to know how quickly the gas reaches the required concentration of 6% before it can sufficiently build up in an animal's lungs and result in loss of consciousness.

Despite that gruesome litany of pain and suffering prior to death in a gas chamber, the AVMA still maintains carbon monoxide for individual or mass euthanasia is a “acceptable for dogs, cats and small mammals."
Neither PVMA president Mark Fox of Rau Animal Hospital, nor the PVMA's executive director Charlene Wandzilak responded to email requests for comment.
Susan Krebsbach, a consultant for the Humane Society Veterinary Medical Association, cited numerous reasons why gassing is unacceptable:
*High gas flow rates result in high noise levels inside the tanks frightening animals.
*Stuffing in multiple animals in at once, which leads to heightened agitation and also dilutes the gas which prolongs suffering.
*Old, sick and wounded dogs with compromised circulatory systems, and also puppies, can take longer to die in a gassing situation.
*Pregnant dogs and cats may die from the gas but the babies they are carrying suffocate.
*Using gas is dangerous and poses health and safety risks to shelter workers. In addition the machines are expensive to maintain.
"When doing euthanasia you want to have a method that is quick and painless, not cause for distress," said Kresbach, who practices in Madison, Wisconsin. "It doesn't make sense that we're still doing this."
One issue that surfaced last year was the cost to train shelter workers to use the injected drug method of euthanasia, but that was resolved, said Irwin. In fact, one shelter that had used gas chambers switched to sodium phenobarbital in the last year, she said.
"We support the current bill," said Irwin.
(Photo: Gas chamber in Lorain County, Ohio. A county ordinance now bans its use.)