Earlier this month, tragedy struck the San Francisco Zoo when Kabibe, a 16-month-old gorilla popular with visitors, was crushed to death by an electric door during a routine night transfer in the zoo’s gorilla enclosure. Following the Nov. 7 incident, the zoo has faced criticism from the public and even five of its own zookeepers who assert that the three decades-old enclosure is not only understaffed, but also has had long-standing problems with its doors and outdated layout, according to an article published by the San Francisco Chronicle.

“It was a freak accident,” animal keeper Corey Hallman told the paper. “But with a workplace that takes safety and keeper input more seriously, it could have been prevented.”

The baby gorilla died after scooting under a closing hydraulic-powered door. The accident occurred during a very normal procedure that zookeepers told The Chronicle can be often chaotic. At night, the gorillas that live in the enclosure are brought to a series of small rooms where they sleep at night, which surround a much larger room located behind the public day viewing area. One zookeeper operates the control panel for the doors, which, according to The Chronicle, offers an obscured view of some of the doors. The operator the night Kabibe died did not keep her hand pressed on the emergency stop button as the door was closing.

The zoo is currently conducting an investigation to find out exactly what went wrong, and find ways to prevent future tragedies from happening. In an editorial for The Chronicle on Nov. 17, Tanya Peterson, the zoo’s president and executive director, wrote that the gorilla exhibit and the greater zoo are “routinely inspected,” and that “the U.S. Department of Agriculture found ‘no non-compliant,’ issues with the exhibit” back in January. In the piece, Peterson acknowledges some of the challenges that the zoo faces – many stemming from the fact that it is a nonprofit organization working in “a city-owned facility with complex labor issues.” Peterson adds that the San Francisco Zoological Society receives a little more than $4 million each year from San Francisco – a figure that has not changed since the 1990s – with operating expenses totaling more than $17 million. Most of the zoo’s funding stems from outside donors and operational funds.

Despite Peterson’s assertions that the zoo facility is operationally sound, outside investigator Dr. Terry Maple, who was brought in to assess the enclosure following Kabibe’s death, suggested that the gorilla holding area be replaced with a more up-to-date system.

Maple found that the holding area doors do not stop closing when they hit an object in the same way a home’s garage door would, and also assessed that the control panel made it “not easy” for the operator to watch each of the doors.

This also isn’t the first time that similar accidents have occurred. In March 2013, the same door got stuck and had to be pried open with a crowbar. The door also collapsed earlier this year. No animals were injured during these events.

“We want the zoo to be a better place,” animal keeper Amy Corso told The Chronicle. “It’s a shame that management sees our recommendations as complaints instead of as suggestions. We are in it for the animals and for the institution.”

The San Francisco Zoo told FoxNews.com that it is unable to comment at this time, while waiting for the full results of Dr. Maple's investigation.

The Associated Press contributed to this report.