While the industry grapples with the new Qualified Opportunity Zone program that is expected to funnel hundreds of billions of dollars into blighted communities across the country, another federal program created to fuel low-income housing development is at risk.

Hundreds of thousands of affordable apartment units built under the federal Low-Income Housing Tax Credit program are slated to hit their 30-year mark between 2020 and 2029 — meaning these units will no longer have to be set aside for low-income housing, Affordable Housing Finance reports.

A recent report by the National Low-Income Housing Coalition and the Public and Affordable Housing Research Corp. found nearly 500,000 LIHTC units in 8,400 buildings, or roughly 25% of existing LIHTC product, that could potentially be converted to market-rate housing once the three-decade period expires — further shrinking the U.S.’ affordable housing stock at a time when the country is experiencing a massive housing shortage and workforce housing crisis.

“The quickly approaching Year 30 deadline creates urgency for solutions,” NLIHC President and CEO Diane Yentel told Affordable Housing Finance. “We must move beyond the status quo of needlessly scarce resources and commit to a longer-term and bolder vision for a comprehensive national housing policy that ensures affordable homes for our nation’s more than 11 million extremely low-income renter households.”

Unless these identified LIHTC units are preserved for low-income housing through additional subsidies in the next decade, the more desirable low-income units in attractive neighborhoods could disappear altogether, with rents rising to such a degree that existing tenants are forced out, Next City reports.