On January 26, the Second Circuit ruled against U.S. Immigration and Customs Enforcement (ICE) in a case that has broad implications for the public’s access to data held in immigration agency databases.

The case stems from an ACLU Freedom of Information Act (FOIA) request. The request asked for data from ICE about removals, detentions, apprehensions, risk classification assessments, and bond. The FOIA request sought information that would shed light on the experiences of individuals who had encounters with ICE at different phases of enforcement.

ICE databases use A-Numbers—unique numbers assigned to noncitizens that could divulge personally identifying information if revealed—as a method to link records that relate to an individual. So, when ICE searches its databases for information about an individual, it can pull all their information by entering their A-Number.

The ACLU’s FOIA request accounted for ICE’s method for maintaining data and the need to keep the A-Numbers private by requesting that ICE produce spreadsheets of data where A-Numbers would be “replaced with anonymous unique identifiers.” The ACLU asked for this so that the public—just like ICE—can understand “the movement of noncitizens across the different stages of the enforcement process, from arrest to detention to deportation or release.”

ICE refused to provide these unique IDs. The agency argued that FOIA didn’t require the agency to produce A-Numbers because that would reveal personally identifying information and didn’t require substituting A-Numbers with Unique IDs because that would constitute the creation of “new records.” The district court agreed.

The Second Circuit, however, reversed the district court’s decision. The court focused on ICE’s use of A-Numbers as the “key” or “code” to pull information about individuals from various databases. It held that FOIA’s “broad disclosure policy” supported a requirement that the agency substitute a different code to provide the public access. In this case, the court held Unique IDs consisting of “any combinations of numbers, letters, or symbols” would serve this purpose and would not constitute the creation of a “new record.”

In reaching its decision, the court considered changes to agency record-keeping and changes to FOIA law that reflected a need for agencies to accommodate requesters who seek data. Changes to FOIA in the Electronic Freedom of Information Act Amendments (E-FOIA), for example, emphasize that agencies must produce records “in any form or format” if it is “readily reproducible by the agency in that form or format.” E-FOIA also requires agencies to make “reasonable efforts to search for the records in electronic form or format.”

In addition, the court pointed out that if ICE were not required to substitute A-Numbers, it could incentivize agencies to hinder government transparency. The court said that a decision in ICE’s favor would have “the perverse effect” of encouraging agencies to connect data that should be disclosed to records exempted from disclosure under FOIA, effectively concealing the information from the public.

This case may have far-reaching consequences for immigration agencies that have collected information in databases in a way that bars meaningful access to information about individual immigrants. As an amicus brief in support of the ACLU pointed out, access to enforcement data is critical to conducting badly needed agency oversight.

In the past, agencies have occasionally provided unique IDs in their discretion, but the Second Circuit affirmed that this policy is not optional. Reasonable steps to improve the public’s access to information are now required for agencies to meet their obligations under FOIA.

Though this decision applies only in the Second Circuit, ICE and other immigration agencies should work to enhance transparency for requesters in all jurisdictions and quickly bring their FOIA policies, including their methods for searching and producing documents, in alignment with the court’s decision.

This post originally appeared on Immigration Impact Reprinted with permission.