Fallout is the sixteenth episode of the second season of Designated Survivor and the thirty-seventh episode overall. It aired on April 4, 2018.
Kirkman and the FBI scramble to find where a "dirty" nuclear waste bomb is planted in the United States and the person responsible for it. The bomb is found at a Metro Line train station but kills six FBI personnel including Director Forstell before they can clear the station. Evidence initially points to East Hun Chiu, but when it proves to be Kunami's doing Kirkman launches airstrikes at strategic targets in that country.
- Kirkman and the rest of the government have to go underground in the face of a dirty nuclear bomb. In order to convince the press that everything is business as usual and to keep the public from panicking, Kirkman leaves the safety of the bunker with Mike in tow to make a public appearance. When he returns to the safety of the bunker, Ellenor Darby tells him that she doesn't want to be president over a game of chess. Kirkman says that he knows, and that if she had wanted to be president, he never would have picked her to be his vice president.
- A second dirty bomb is planted in Brandt metro station. Forstell runs toward the subway to try to warn his agents inside and he dies in the blast. Kirkman releases a statement on the issue.
- Joon Kim is set up by Kunami to take the blame for the dirty bombs. Kirkman meets with the Kunami ambassador and makes his demands. Kirkman wants to strike back immediately, but his advisors tell him to wait. Kirkman reminds them that it took 18 months for them to get justice for the Capitol bombing because they didn't know who did it, but they know where the Emir is. They relinquish, and Kirkman orders the attack.
- Kiefer Sutherland as Tom Kirkman
- Natascha McElhone as Alex Kirkman
- Paulo Costanzo as Lyor Boone
- Adan Canto as Aaron Shore
- Italia Ricci as Emily Rhodes
- LaMonica Garrett as Mike Ritter
- Zoe McLellan as Kendra Daynes
- Ben Larson as Damian Rennett
- Kal Penn as Seth Wright
- Maggie Q as Hannah Wells
- This is Forstell's last episode.