California’s fire safety regulators are finally out with a ‘single stair’ report. They don’t love the idea

California's Office of the State Fire Marshal has released a long-awaited report expressing skepticism about allowing mid-rise apartment buildings to be constructed with only one staircase, a practice common in many other countries but currently prohibited in the state.

The report, published two months past its statutory deadline, concludes that while modern safety features like sprinkler systems and smoke detectors reduce fire risks, they cannot fully replace the safety redundancy provided by dual staircases in buildings over three stories.

The single-stair debate has gained momentum among housing advocates, architects and YIMBY activists who argue that California's requirement for dual staircases in mid-rise buildings makes development more expensive and limits the ability to build smaller, affordable units on compact urban lots.

They point to successful single-stair apartment buildings in Europe and other regions as evidence that the practice can be safe while enabling more efficient use of valuable city land.

Despite the fire marshal's cautious assessment, at least one Democratic legislator plans to introduce legislation that would modify the state building code to permit single-stair construction.

For property developers, such changes could potentially reduce construction costs and allow for more flexible building designs on smaller parcels, though any new regulations would likely include additional safety requirements to compensate for the reduced egress options.