Back in January, Delta announced changes to its policies surrounding emotional support animals on planes, introducing a more rigorous vetting process and banning certain animals from being eligible for the "emotional support" label (sorry—no more sugar gliders). Now, the policy has become even more stringent, as Delta will limit passengers to one emotional support animal and place an all-out ban on "pit bull type dogs" as service or support animals. The changes, announced yesterday, will take effect July 10.

Though Delta hasn't specified what breeds or mixes could fall under the "pit bull type" designation, it says the ban is inspired by "recent incidents in which several employees were bitten." When asked for specifics, Ashton Kang, a Delta spokesperson, referenced a recent flight between Atlanta and Tokyo-Narita, in which two employees were reportedly bitten by a customer's emotional support animal, a pit bull, during the boarding process. Delta also cited an 84 percent increase in "reported incidents involving service and support animals since 2016, including urination/defecation, biting, and even a widely reported attack by a 70-pound dog."

"The safety and security of Delta people and our customers is always our top priority," Gil West, Delta's chief operating officer, said in a statement. "We will always review and enhance our policies and procedures to ensure that Delta remains a leader in safety."

While this is the first banning of a specific dog breed by an airline, legislation that singles out pit bulls is nothing new. Hundreds of cities in the U.S. have "breed-specific legislation" (BSL) in place, with laws that often focus on pit bulls. BSL has become a rallying cry for pit bull owners and advocacy organizations like the American Pit Bull Organization, who have said danger lies in poor training, not the breed of the dog itself.

If the airline industry's past track record is any indication—United and American quickly followed Delta with their own changes to emotional support animal policies earlier this year—this latest move could inspire other carriers to enact similar policies.