A bunker door and stairway sit ready for installation as Ron Hubbard, owner of Atlas Survival Shelters, gives a tour of his company's operations in Sulphur Springs, Texas, on Aug. 27, 2024, (AP Photo/LM Otero)
The owner, who asked not to be identified because of concerns about his privacy, walks up the steps of his underground shelter in an undisclosed Southern California city, on Dec. 16, 2024. (AP Photo/Jae C. Hong)
A bedroom is shown inside an underground shelter in an undisclosed Southern California city, Monday, Dec. 16, 2024. (AP Photo/Jae C. Hong)
Bunk beds are seen inside an underground shelter in an undisclosed Southern California city, on Dec. 16, 2024. (AP Photo/Jae C. Hong)
Brooke Buddemeier, a radiation safety specialist at Lawrence Livermore National Laboratory, stands in front of a screen showing the impact of nuclear detonation, in Livermore, Calif., Thursday, Aug. 22, 2024. (AP Photo/Terry Chea)
The owner, who asked not to be identified because of concerns about his privacy, turns off the lights in his underground shelter in an undisclosed Southern California city, on Dec. 16, 2024. (AP Photo/Jae C. Hong)
A dining area inside an underground shelter is seen in an undisclosed Southern California city, Monday, Dec. 16, 2024. (AP Photo/Jae C. Hong)
Ron Hubbard, owner of Atlas Survival Shelters, talks about the bunker his company is building for a client during a tour of his operations in Sulphur Springs, Texas, on Aug. 27, 2024, (AP Photo/LM Otero)
HOLD FOR USE WITH STORY-Brooke Buddemeier, a radiation safety specialist at Lawrence Livermore National Laboratory, sits for an interview at the National Atmospheric Release Advisory Center in Livermore, Calif., Aug. 22, 2024. (AP Photo/Terry Chea)
Michael Dillon, a researcher at Lawrence Livermore National Laboratory, sits for an interview at the National Atmospheric Release Advisory Center in Livermore, Calif., on Aug. 22, 2024. (AP Photo/Terry Chea)
Ron Hubbard, owner of Atlas Survival Shelters, talks about concrete bunkers during a tour of his operations in Sulphur Springs, Texas, Tuesday, Aug. 27, 2024, (AP Photo/LM Otero)
The owner, who asked not to be identified because of privacy concerns, walks out of his underground shelter in an undisclosed Southern California city, on Dec. 16, 2024. (AP Photo/Jae C. Hong)
The owner, who asked not to be identified because of privacy concerns, shows water tangs in his underground shelter in an undisclosed Southern California city, Monday, Dec. 16, 2024. (AP Photo/Jae C. Hong)
Two toilets are seen inside an underground shelter in an undisclosed Southern California city, on Dec. 16, 2024. (AP Photo/Jae C. Hong)
Ron Hubbard, owner of Atlas Survival Shelters, wears tennis shoes with a message during an interview at his company's office in Sulphur Springs, Texas, on Aug. 27, 2024, (AP Photo/LM Otero)
Ron Hubbard, owner of Atlas Survival Shelters, stands in a bunker his company is building for a client on Aug. 27, 2024, in Sulphur Springs, Texas. (AP Photo/LM Otero)
Ron Hubbard, owner of Atlas Survival Shelters, walks over to concrete bunkers during a tour of his operations in Sulphur Springs, Texas, on Aug. 27, 2024, (AP Photo/LM Otero)
Brooke Buddemeier, a radiation safety specialist at Lawrence Livermore National Laboratory, stands in front of a screen showing the impact of a nuclear detonation on various buildings, in Livermore, Calif., on Aug. 22, 2024. (AP Photo/Terry Chea)
Chris Pettis helps installs a safe in a bunker under construction for a client at Atlas Survival Shelters in Sulphur Springs, Texas, on Aug. 27, 2024, (AP Photo/LM Otero)
The owner, who asked not to be identified because of concerns about his privacy, turns on the lights in his underground shelter in an undisclosed Southern California city, on Dec. 16, 2024. (AP Photo/Jae C. Hong)
Anton Kytaiev, right, works on a social media post for Ron Hubbard, owner of Atlas Survival Shelters, at the company's office in Sulphur Springs, Texas, Tuesday, Aug. 27, 2024, (AP Photo/LM Otero)
Ron Hubbard, owner of Atlas Survival Shelters, handles a shotgun during an interview at his company's office in Sulphur Springs, Texas, Tuesday, Aug. 27, 2024, (AP Photo/LM Otero)
Ron Hubbard, owner of Atlas Survival Shelters, walks out the door of a bunker his company is building for a client during a tour of his operations in Sulphur Springs, Texas, on Aug. 27, 2024, (AP Photo/LM Otero)
Brooke Buddemeier, a radiation safety specialist at Lawrence Livermore National Laboratory, holds a nuclear detonation response guide at the National Atmospheric Release Advisory Center in Livermore, Calif., Thursday, Aug. 22, 2024. (AP Photo/Terry Chea)
The owner, who asked not to be identified because of concerns about his privacy, closes the heavy metal door of his underground shelter in an undisclosed Southern California city, Monday, Dec. 16, 2024. (AP Photo/Jae C. Hong)
Ron Hubbard, owner of Atlas Survival Shelters, pauses during an interview at his company's facilities in Sulphur Springs, Texas, on Aug. 27, 2024, (AP Photo/LM Otero)