SAN FRANCISCO (KCBS) — Animal rights activists say a loophole in California laws allows shelters to euthanize animals in gas chambers, and are trying to put an end to the practice.

California has banned several gasses for euthanasia since 1998, but carbon dioxide was left off the list. The Humane Society, acting on a tip, found what California Director Courtney Fern said was the last animal shelter using gas chambers to put animals down.

READ MORE: Dozens of Dogs, Cats Removed From Danville Home

The SFSPCA made the shelter in Coalinga an offer.

“Do you want assistance in transitioning into the standard of euthanasia by injection? Do you want the training on how to perform euthanasia by injection? They were extremely cooperative. They were excited that they would be able to transition away from this,” Fern told KCBS.

READ MORE: Oakland Church Group Hosts Party to Preach Anti-Violence by Practicing Community

Meanwhile, Hayward Assemblyman Bill Quirk has introduced a bill that would completely ban the use of gas chambers in animal shelters.

“When I saw the scientific findings about how it induces pain and panic, I took the legislation, and moved it forward,” Quirk told KCBS.

MORE NEWS: 18-Year-Old Man Shot Dead, Another Wounded Saturday in Bay Point

The initiative is on its way to the State Senate.