When performed properly, euthanasia by injection of sodium pentobarbital is the safest, most humane method, and the least stressful to the animal. Historically, the lack of access to these drugs has been an issue for shelters. In 2013, the Texas Humane Legislation Network passed a bill that prohibits the use of carbon monoxide gas as a means of euthanasia in Texas animal shelters, allowing only EBI. This bill passed without any oppositional votes and signed by Governor Perry on May 10, 2013. Over 15,000 shelter dogs and cats euthanized by carbon Monoxide in 2012.