PITTSBURGH — The Pittsburgh Zoo & PPG Aquarium is dropping its membership in a major accrediting organization following differences over a new safety policy limiting contact with elephants.

The zoo said that it had “a philosophical difference of opinion” with the Association of Zoos & Aquariums, which said the two disagreed over a policy scheduled to begin in June 2017 that would limit unrestricted access between handlers and elephants to times of transport, research, calf management and medical treatment.

“The Pittsburgh Zoo believes very strongly that decisions regarding our Zoo’s animals must be made by the professionals who are knowledgeable about the institution’s programs and staff and specifically trained to handle our animals,” zoo president Barbara Baker said in a statement.

The zoo said it was also accredited by the Zoological Association of America and the Alliance of Marine Mammal Parks and Aquariums, regulated by federal authorities and a member of more than 30 other organizations such as the World Association of Zoos and Aquariums, the International Elephant Foundation and the American Association of Zoo Veterinarians.

The Association of Zoos & Aquariums said it was disappointed that the zoo had “decided their status quo was preferable to complying with the AZA’s more rigorous occupational safety standards related to caring for elephants.” Its senior vice president for external affairs, Rob Vernon, said Pittsburgh is the only zoo to have left it over the issue.

In November 2002, an elephant handler at the Pittsburgh Zoo was killed by a 3-ton African elephant during a walk through the zoo’s campus.

In February, the U.S. Department of Agriculture ordered the zoo to stop using cattle dogs in handling elephants, saying that could cause “behavioral stress” to the elephants. The zoo said having dogs read animal behavior and alert keepers to any disruption was considered “a low-stress method” of animal management in the livestock field.

People for the Ethical Treatment of Animals, which complained last year about the use of dogs, criticized the zoo’s stance, saying “modern elephant programs always use barriers to separate elephants and handlers, protecting both.”