The ABC7 News I-Team investigation began with an unsigned letter from someone describing themselves as "a friend of zoo workers" who is concerned about their safety. Then, we filed a public records act request and received internal zoo documents that show problems in the code red system.
A group of employees from the San Francisco Zoo are taking an extraordinary step -- going on camera to say safety at the zoo could be better -- that it should be better. They have seen first-hand, this can be a life or death issue.
"I went home at the end of the day with chunks of meat and blood in my hair on me," animal keeper Corey Hallman said.
Hallman watched a tiger mangle his co-worker's arm -- she survived and still works at the zoo.
Zoo administrative worker Wesley Haug was there one year later on Christmas Day when the same tiger, Tatiana, leapt from her grotto and killed 17-year-old Carlos Sousa, Jr. There were reports, never proven, that Sousa's two friends had taunted the tiger.
Police shot and killed the 350 pound cat.
"I saw Tatiana almost every day; I'd go by before I left," Haug said. "It was such a beautiful cat and for this to happen; it was devastating."
In response to the mauling, the zoo spent more than $27,000 on a "code red" alert system with personal panic buttons for keepers working with the most dangerous animals, horns to broadcast a warning tone and a message telling visitors to find shelter, and a computer system that automatically called the police.
But, keepers sometimes triggered the alarm by accident.
"They never gave us any kind of protective case or gear to prevent that from happening," Hallman said. "So, many of the employees got creative and took bottle caps and duct taped them over it."
After some of the buttons suffered water damage, the zoo, without consulting the worker safety committee, decided to mount all the alarm buttons on the wall.
The animal keepers union representative calls that a mistake.
"If you are being mauled by a tiger, you can't say, 'Excuse me one second, I need to run over and press this button,'" Tim Jenkins said.
Zoo Director Tanya Peterson and her spokesperson repeatedly denied requests for an interview, so Dan Noyes caught up to her at the zoo last week to ask several important questions.
Dan Noyes: "Why put the buttons up on the wall instead of on the keeper's person. I mean, if I'm being attacked, it might be hard to reach the wall, right?"
Tanya Peterson: "Well, you know what, we did have a keeper unfortunately attacked by a tiger. It was the buddy system and another person was there, so we feel that the buddy system is a more important offensive process for safety."
She said the buddy system and radios are most important to keeping workers safe. Peterson and her team have altered the "code red" system -- cutting the automatic notification to San Francisco police and removing the verbal message.
Dan: Is it important to have the buttons working for you?"
Tanya Peterson: "The buttons are a secondary system. It's a public alarm system. We're actually concerned that they create mayhem."
That worries zoo workers. They've lost confidence in Peterson and how she and her staff maintain the "code red" system.
"I walk through the Zoo every day and it's always on my mind; OK, are we safe or could we be safer," Haug said.
"I think that we should be a world class leader in safety, based on our past experience," Operations Shop Steward Steve Levitt said.
The workers want a simple test, just like a fire drill -- push each of the 10 "code red" buttons and hear the alarm go off.
The zoo refuses, instead testing parts of the system at different times, and staging exercises like one from December.
Tanya Peterson: "I'm going to ask everyone to go in lockdown, he is approaching the front gate, he may be armed."
Peterson devised a scenario in which a gunman is looking for his ex-wife, a zoo employee. She signals a staff member to push a code red button.
Tanya Peterson: "Main Desk, in fact, why don't you hit the panic button for me?"
Main Desk: "10-4 pushing the panic button."
The alarm doesn't sound. Peterson tries again.
Tanya Peterson: "Could you just make someone hit the panic button so everybody knows? I'm going to take these people up and lock them down here."
Again, nothing. More than five minutes pass, until the head of it struggles to manually sound the alarm.
Durant Chow: "I'm trying to do it manually now, it's going, but it's not sounding."
The I-Team found more problems with the "code red" system in public records:
2011: System malfunctioned and sent out false alert
2012: "Recorded message on the speaker system was inaudible"
2013: test of panic buttons in bears and administration "outright failed." the button in snow leopards had no batteries and no wiring.
"It wasn't hooked up to the system," Jenkins said. "So, one of my members who works at snow leopards thought for over two years, if she was in trouble she could push that button and it would work and it didn't. It never worked."
The I-Team took what it found to the San Francisco Recreation and Parks Commission, which oversees the zoo.
"Frankly, my concerns as chair of the Joint Zoo Committee are really around the inability of frankly both sides to move beyond the rhetoric and get to let's find workable solutions," Rec and Parks Commissioner Eric McDonnell said.
Carlos Sousa says after the tiger killed his son, he found some comfort knowing the zoo tried to be safer with the "code red" system. Now, he wants them to get it right.
"I think they should, you know, fix that problem and make sure it works for all the employees, so the employees are safe and the people that go to the zoo are safe," Sousa said.
The zoo has just announced it's spending $170,000 on new radios that have a panic button -- that does not address how the public will be warned about a dangerous animal on the loose.
The zoo put out a statement late Thursday saying in part, "The zoo has full confidence in our safety procedures...and has received full and complete certifications from all of our oversight organizations, including the Association of Zoos and Aquariums and the USDA."