The Internal Revenue Service is building a new system that would give federal immigration agents unprecedented access to confidential taxpayer data—most notably, home addresses—according to a technical blueprint obtained by ProPublica.
The system is designed to allow U.S. Immigration and Customs Enforcement (ICE) to request and receive address information from tax records “on demand,” a significant shift in how sensitive tax data is shared with law enforcement.
Last month, Andrew De Mello, then the IRS’s acting general counsel, pushed back against a request from ICE to release addresses for 7.3 million taxpayers. In an internal email, De Mello cited multiple legal deficiencies in ICE’s mass data request, including the lack of evidence that each taxpayer was the subject of a criminal investigation—a requirement under federal law. Two days later, on June 27, De Mello was removed from his post.
Though the IRS has yet to hand over the requested addresses, internal sources say the system’s development continues, with plans to launch by the end of July.
A Legal and Political Flashpoint
The push to access taxpayer data dates back to the Trump administration. Soon after Trump took office, the Department of Homeland Security (DHS), which oversees ICE, began pressuring the IRS to share tax information as part of a broader effort to facilitate mass deportations. A 2019 memorandum of understanding between the two agencies provided limited legal grounds for such data-sharing, but also included key guardrails.
De Mello’s refusal to release the data was rooted in those legal protections. “There’s just no way ICE has 7 million real criminal investigations—that’s a fantasy,” said a former senior IRS official involved in advising the agency.
Until recently, law enforcement agencies were required to make highly specific, narrow requests for tax data—typically one individual at a time. The new system, however, would automate the process and allow for bulk data transfers, bypassing case-by-case legal review.
Engineers Warn of Risks
The blueprint reviewed by ProPublica outlines a system where DHS submits spreadsheets with names and prior addresses of deportation targets. The IRS system would match these entries to tax records, pull the latest known addresses, and return a new spreadsheet to ICE. IRS engineers involved in building the platform fear it could lead to errors, including agents targeting the wrong individuals due to mistaken identity.
“This program, as it’s currently designed, makes it highly likely that incorrect addresses will be shared,” said one IRS engineer. “That could lead to raids at the wrong homes.”
Engineers also warn that the system lacks limits on how much data ICE can request or how often. In its current form, it could be modified to extract far more information than just addresses—such as employer names or family relationships.
The development is taking place in IRS facilities in Lanham, Maryland, and Dallas. Several IRS employees have reportedly declined to work on the system due to concerns about legality and personal liability.
Legal and Political Fallout
In March, immigrant rights groups sued to block the IRS-DHS agreement, arguing it violated federal privacy laws. A federal judge upheld the deal in May, but the technical blueprint wasn’t available during the ruling. The case remains open, and the system could still be subject to legal scrutiny.
Privacy experts and lawmakers are alarmed by the potential for abuse. Sen. Ron Wyden, the top Democrat on the Senate Finance Committee, warned the system “would allow an outside agency unprecedented access to IRS records… opening the door to endless fishing expeditions.”
Under federal law, unauthorized disclosure of taxpayer data is a felony punishable by up to five years in prison. The IRS has long told taxpayers—especially undocumented immigrants using Individual Taxpayer Identification Numbers (ITINs)—that filing taxes would not expose them to deportation.
“This represents a major breach of that promise,” said Nandan Joshi, an attorney with Public Citizen, which is seeking to stop the program.
Political Pressure Mounts
According to sources, DHS leaders are under pressure from the White House to meet a goal of deporting 3,000 people per day. One federal agent involved in deportations said recent raids were hampered by outdated address data, suggesting that access to IRS records would dramatically speed up operations.
Internal meetings show the extent of DHS’s ambitions. At one point, an ICE official suggested that the IRS simply return all addresses in a state that match a given name—an idea IRS lawyers said could expose them to criminal prosecution.
The project is developing amid broader changes to IRS leadership and culture. Elon Musk’s former associate Sam Corcos, who briefly led the IRS’s tech division, ousted over 50 engineers and initiated a data overhaul during the Trump administration. Corcos, now at the Treasury Department, has also been involved in building a “master database” of federal records using software from Palantir Technologies.
The IRS said the data-sharing agreement complies with Section 6103 of the tax code, which governs law enforcement access to returns. The Treasury Department echoed this in a statement, saying the MOU had been upheld in court and is “a lawful application” of tax disclosure laws.
However, recent documents reviewed by ProPublica reveal efforts to further expand the agreement. A draft proposal by an ICE attorney last month sought authorization to collect IRS data on U.S. citizens and green card holders suspected of “criminal activities.” De Mello reportedly rejected the proposal, demanding that any such expansion be approved by Treasury leadership.
A Shift in Mission
Critics say the plan threatens to erode trust in the tax system by turning the IRS into an immigration enforcement tool. “The IRS’s mission has always been about collecting revenue, not conducting raids,” said a former official.
As the White House doubles down on aggressive deportation efforts, the line between law enforcement and revenue collection is blurring.
“This isn’t a surveillance program,” said White House spokesperson Abigail Jackson. “It’s part of President Trump’s promise to remove criminal illegal aliens—a promise he’s keeping.”
