The possibility of turning vacant commercial space into future housing on Oahu is under consideration with a newly proposed city measure.

The Honolulu City Council is expected to consider Bill 21, introduced by Council member Tyler Dos-Santos Tam earlier this year, which is intended to provide flexibility for certain ventilation and lighting requirements related to local, state and international building codes.

In particular, Dos-Santos Tam, who represents the Downtown and Chinatown areas of Honolulu, aimed this bill at empty commercial spaces found in those locales, including the Walmart at Fort Street Mall, which permanently shuttered on Friday due to underperformance. Walmart opened its 80,000- square-foot store there in 2014, replacing the Macy’s outlet that vacated the spot the year prior.

“The idea of Walmart turning into a dark, hulking shell is terrifying. Crime in Chinatown is bad enough, empty space will only make it worse,” Dos Santos-Tam said in a written statement. “We need solutions, and we need solutions now. That’s why I proposed Bill 21.”

He notes similar exemptions for office-to-residential conversions have been provided for downtown projects.

Those included one at 1132 Bishop St.: an office tower that company Douglas Emmett Inc. converted into a high-rise apartment project called The Residences at Bishop Place. The other is at Fort Street Mall: a 17-story affordable housing project for older adults within the mall’s property and planned, in part, by Catholic Charities Housing Development Corp.

If approved, Dos Santos- Tam said, Bill 21 would increase the frequency of this practice.

As drafted, Bill 21 relates to ventilation and natural light for multifamily housing “by means of windows or skylights with an area of not less than one-tenth of the floor area of such rooms with a minimum of 10 square feet.”

Richmond Luzar, Dos- Santos Tam’s policy and communications director, said Honolulu has a housing code in addition to the International Building Code and International Residential Code. He added that the city’s housing code was adopted decades ago and “is not a model code, so it hasn’t been updated regularly.”

“One of its provisions requires that all bedrooms be built to allow for natural light and ventilation via windows of a certain size,” Luzar said. “This provision makes it difficult to convert office space to residential because, in many cases, offices don’t meet the windows requirement.”

He added that a building might have air conditioning and artificial lighting but windows that are too small or don’t open far enough.

“If someone wanted to convert the space, they would either have to retrofit every single bedroom or get an exemption” from the city Department of Planning and Permitting, Luzar said. “Essentially, it would either be super costly or take super long.”

Meanwhile, Bill 21 has received support from housing advocates like Housing Hawaii’s Future and Hawaii YIMBY. The measure, according to Dos Santos-Tam, also has been supported by DPP. And so far, Bill 21 has passed its first reading and is currently in the Council’s Committee on Zoning.

Dos Santos-Tam said the measure will continue to be “refined” over the course of two more Zoning Committee meetings and two more full City Council meetings.

As far as anyone taking over the Walmart site for a residential project, according to Luzar, there has been no official declaration from any developer over converting the empty Walmart space into residences.

However, Luzar asserted that Christine Camp, president and CEO of real estate development company Avalon Group Hawaii — which is currently doing another office-to-residential conversion that’s already received a DPP exemption — has expressed interest.