(CBS) — Delta Air Lines is tightening its rules on emotional support and service animals, citing “growing safety concerns” that include a recent incident in which two workers were bitten.

The updated policy, which takes effect July 10, limits passengers to one emotional support animal each and bans “pit bull type” dogs as service or support animals on flights.

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“These updates, which come as the peak summer travel season is underway, are the direct result of growing safety concerns following recent incidents in which several employees were bitten,” the airline said.

Several dog breeds are commonly defined as related to pit bulls, including some terriers and bulldogs. Delta clarified its ban as including “pit bull mixes.”

The latest incident occurred last week in Atlanta, when “two employees were bitten by a customer’s emotional support animal,” a Delta spokesperson emailed. “One employee received medical treatment onsite and the customer and animal were removed from the flight” bund for Tokyo, the carrier added.

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The airline carries about 700 service or support animals each day, or nearly 250,000 annually. Delta said it’s experienced an 84 percent increase in reported incidents involving service or support animals, including urination and defecation, as well as an attack on a passenger by a 70-pound dog last June.

Delta said it was looking to ensure the safety of customers and employees, while also “supporting the rights of customers with legitimate needs, such as disabled veterans, to travel with trained service and support animals.”

Passengers have tried to fly with comfort turkeys, gliding possums, snakes, spiders and more, said Delta, calling out those “ignoring the true intent of existing rules.”

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Major U.S. airlines have been changing their policies on animal travel as the carriers deal with health and safety issues affecting humans and pets. The incidents included the the death of a 10-month-old puppy in an overhead compartment of a United Airlines flight in March.