Putting cats and dogs to death by subjecting them to carbon monoxide would be banned under legislation unanimously approved March 28 by the Texas Senate.

More than 100,000 animals are euthanized each year in Texas shelters, and gas chambers are still used in 30 state shelters, according to backers of Senate Bill 360.

"Killing dogs and cats with carbon monoxide is cruel, expensive and dangerous," state Sen. Kirk Watson, the Austin Democrat who authored the act, said in a Facebook post.

Injection is the only euthanasia method approved by The Association of Shelter Veterinarians, which says that carbon monoxide stimulates motor centers in the brain that can cause convulsions in dying pets and delay unconsciousness and death.

Sixteen states, as well as several Texas cities — including San Antonio, Houston and Austin — have already banned gas chambers for pet euthanasia.

“Virtually every national sheltering agency and veterinarian association agrees that euthanasia by injection is the preferred and humane method for shelter euthanasia,” Watson said in his statement. “The use of carbon monoxide gas is now outdated and should be eliminated.”

Senate Bill 360 has the support of several animal welfare groups, including the Texas Humane Legislation Network and the American Society for the Prevention of Cruelty to Animals.

The measure will now go to the House of Representatives for consideration.

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Laura Moss writes about a variety of topics with a focus on animals, science, language and culture. But she mostly writes about cats.

Texas Senate passes ban on gas euthanasia for shelter pets
16 states have banned the use of carbon monoxide to euthanize cats and dogs.