What Is The Safeguard Procedure In Silo? Everything We Know So Far

"Silo," an Apple TV+ drama series based on the trilogy of the same name by Hugh Howey, follows a civilization living in an underground silo. In this dystopian future, it's believed that the surface is toxic due to an apocalyptic event that happened over 100 years before. Not an uncommon premise in the genre by any means. However, unlike other popular shows, the silos in "Silo" are being controlled by something other than the thousands of people who live in them.

The Safeguard Procedure first came up in a letter from Salvador Quinn, the head of IT in Silo 18 140 years ago. At that time, there was a rebellion in the making, something that the individuals behind the silos wouldn't approve of. The coded letter references that "the fate of this silo is determined by another" and that someone within the silo can "kill everyone here in an instant." When Lukas Kyle (Avi Nash), a systems analyst, discovers what the letter says at the bequest of his superior and goes to the tunnel Quinn mentions in the closing lines, a voice called the Algorithm lets him in on what will happen if he tells anyone what he's found.

If you are still confused about what the Safeguard Procedure is, or what it could mean for the future of Silo 18, don't worry. We've put together everything we know so far about the Safeguard Procedure in "Silo."

The Safeguard Procedure is a method of population elimination. The audience, and Lukas, finds out there are specific missions designed by founders of the silos, more than just developing a place for the human race to escape to when the surface became inhabitable. It means that the creators want to be able to control what happens within the silos and make sure they are still fulfilling the initial goals, though it isn't clear who made the silos or what their intentions were. In addition to leadership maintaining order, there is the overarching entity called the Algorithm.

The Algorithm acts as the eyes and ears to ensure a silo is still on track. If for whatever reason the occupants of the silo steer from the course the founders set (like at the end of "Silo" Season 1), or leadership reveals that they know about the Safeguard Procedure or information the general population shouldn't know, the Algorithm will activate the procedure. This causes lethal gas to spread throughout the silo from a pipe in Level 14. It would kill all the people living in it. While this may seem like an extreme measure, there are 50 silos, so the creators viewed the potential loss of a couple as inconsequential. 

Part of the Algorithm's initiative is to keep the individuals of the silos from learning the truth. It was designed to make sure the inhabitants don't know what happened outside, don't know who made the silos or why, don't know that there are others, and don't know why they were selected to be in them. Should their knowledge change, it would trigger the Safeguard. 

While the Algorithm doesn't tell Lukas the explicit reasons for this, or what would officially cause it to enact the Safeguard Procedure, it's a safe bet that if the rebellion goes further in Silo 18, there's a chance the Algorithm may turn it on. Lukas isn't the only individual from Silo 18 to know about it, either. Juliette (Rebecca Ferguson) learns about it when she interacts with former Silo 17 inhabitant Solo (Steve Zahn), where they plugged the pipe the gas would dispense from.

If Lukas were to tell other people about the tunnel, which could lead to the outside world or other silos, this would be considered a sign of rebellion and could lead to people learning the truth of their situation, so the Algorithm would be forced to act. Lukas does tell Bernard (Tim Robbins), the head of IT in Silo 18, about the Safeguard, but there's a chance he already knew. Bernard has a key that glows anytime something seemingly goes wrong within the silo, which always causes him to go behind a closed door, likely where the Algorithm talks to him. These could be warnings that the system is close to initiating the Safeguard.

Season 3 could explore Lukas and Juliette using their newfound knowledge to try and prevent the Safeguard Procedure from taking place. This could be by helping tame the rebellion going on within Silo 18, but it could also mean following the path of Silo 17 and blocking the pipe. No matter what happens, it looks like it will be a race to save the population of Silo 18 from the Algorithm.