"I'd say it's even more massive and more sprawling than ['The People v O.J. Simpson]," executive producer Brad Simpson told reporters Tuesday following a panel for their Emmy-nominated series at the Television Critics Association press tour.
Simpson explained that they put great effort into not retreading any ground with the second installment, which is not yet officially titled. That meant they didn't want to do a story about another trial, another murder or even anything set in the '90s.
"We wanted to do something that would still have the epic quality and the thing you remember from Katrina is everybody sitting in their bedrooms and watching these people on their roofs going, 'How can we not help them? How is this happening?'" he said. "And what we want to do is go behind the scenes of that and explain this is the reason [officials] weren't prepared to help them."
Producers have chosen a book that will guide their story for the new installment, Simpson added, but he declined to name it.
For the first season, producers used author Jeffrey Toobin's novel "The Run of His Life" for guidance.
The most important thing, Simpson said, is to tonally "match the show to the crime."
"'O.J.' had a satirical edge to it ... with Katrina, it doesn't have that same pop quality," he said. "I think that there's tragedies that are happening throughout it in a way that 'O.J.' doesn't have."
Subject to actor availability, Simpson said they plan to use many actors from the first season of "American Crime Story" for the new season -- if they have characters for which they'd be a good fit.
Simpson coyly declined to name any of the real-life people or officials viewers will be seeing portrayed, but said some characters will be less familiar names.
"It's always fun to find out what was really going on behind the scenes with the famous people, but beyond that, finding characters that you didn't know were going through such an enormous struggle is a ton of fun," he said. "It's like we're writing our own nonfiction book about Katrina."
The new season will comprise of at least 10 episodes, with more possible if needed, Simpson said. He said it will also cover a smaller period of time than "The People v O.J."
"[It] will be much more compact, but it's packed full," he said. "But we'll still be leaving stuff out because so much happened during Katrina."
Production will take place in both New Orleans and Los Angeles.
The new season is set to debut in 2017.