Update June 21, 4:55 p.m. EST: Matt Bershadker, CEO of the American Society for the Prevention of Cruelty to Animals (ASPCA), said Delta's new policy banning pit bulls spreads "false and life-threatening stereotypes."

“Every dog is unique, even dogs within the same breed, and their behavior is influenced by many factors,” Bershadker said in a Twitter statement. “Delta Airlines should resist unwarranted breed prejudice and rescind its breed ban.”

Original story: Delta Air Lines will limit each passenger to one emotional support animal and will prohibit pit bulls as service or support animals on flights, effective July 10.

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It's a further tightening of the Atlanta-based airline's policy on emotional support and service animals.

Delta said the latest policy changes are due to "growing safety concerns" after two employees were bitten by a passenger's emotional support animal last week.

The incident occurred in Atlanta during boarding of a flight to Tokyo Narita, and one employee was medically treated on site, according to the airline. The passenger and animal were removed from the flight.

Delta said when the new policy takes effect it will no longer accept "pit bull type dogs" as service or support animals.

Delta said when the new policy takes effect it will no longer accept “pit bull type dogs” as service or support animals. (File photo)
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The changes come after a Delta passenger was mauled by an emotional support dog on a flight last year.

Delta said it carries 700 service or support animals a day. Since 2016, the airline said it saw an 84 percent increase in reported incidents involving service and support animals, including urination or defecation and biting.

"Customers have attempted to fly with comfort turkeys, gliding possums, snakes, spiders and more," Delta said. "Ignoring the true intent of existing rules governing the transport of service and support animals can be a disservice to customers who have real and documented needs."