CINCINNATI — The barrier separating primates and humans inside the Cincinnati Zoo was just fine — right up until the moment a child fell into the gorilla exhibit May 28.

That's the takeaway of a new federal report that concluded the zoo's barrier was not in compliance with standards for housing primates when a 3-year-old boy made international news by scaling a fence and falling 15 feet into a moat. That fall allowed Harambe, a 17-year-old gorilla, to reach the child and drag him around, ultimately forcing zoo officials to fatally shoot the primate.

The report, from the U.S. Department of Agriculture, issued a critical citation because the barrier failed and caused an animal to be harmed. Before the child fell into the exhibit, however, the zoo had not been cited for shortcomings with that exhibit's barrier during previous inspections.

In short, it's a complicated way of saying that everything would have been fine at the zoo had a child not fallen into the gorilla exhibit, but because one did, the barrier failed.

"Up until May 28, there hadn't been any issues, so they were in compliance," USDA spokeswoman Tanya Espinosa said. "It's ultimately their responsibility to make sure that their barrier restricts contact between the public and non-human primates."

The zoo so far doesn't face fines or penalties, but an investigation is still ongoing. Espinosa said zoo officials "swiftly and comprehensively" updated the barrier following the gorilla's death, which meant it was once again in compliance with federal standards.

The federal standards for primate barriers are vague. They don't specify height, materials or other physical characteristics. The only requirement is that they keep humans and animals apart.

The report goes on to state that the zoo's dangerous-animal response team followed proper procedures after zoo visitors called 911 to report a child in the gorilla enclosure.

A team member concluded that the child was in "life-threatening danger," and Harambe was killed.