Updated May 27 at 2:30 p.m.

Members of Congress from Massachusetts and Maine are demanding the oversight office for the Department of Homeland Security launch a formal investigation into the Boston asylum office’s abnormally low rate of approving asylum applications.

In a letter sent Thursday to the Office of the Inspector General, the delegation wrote they’re concerned over a report that only 15.5% of asylum applicants reviewed by the Boston asylum office between 2015 to 2020 were approved, which is roughly half of the national average of 28%. This is the second-lowest in the nation after the New York asylum office.

In an emailed message, Sen. Ed Markey, D-Mass., who led the letter, said the group is “demanding answers” and wants to ensure that applicants get “fair and proper treatment” in the asylum process.

“Asylum seekers should not have to worry that their applications might be rejected by officers who improperly exert excessive influence or allow hateful bigotry towards immigrants to influence their decisions,” Markey said. The message was also signed by Democrats Sen. Elizabeth Warren, Reps. Jim McGovern, Jake Auchincloss, Lori Trahan, Ayanna Pressley, Katherine Clark, and Rep. Chellie Pingree of Maine.

After this story published, a spokesperson for the U.S. Citizenship and Immigration Services — which oversees the Boston asylum office — sent a statement saying "USCIS adjudicators evaluate every petition and application fairly, humanely, and efficiently on a case-by-case basis before issuing a determination, and agency employees welcome people from all parts of the world to add their unique skills and talents to the American fabric."

The lawmakers wrote that denying legitimate asylum claims without proper due process exposes asylum seekers from the prosecution they fled if they are deported.

There are around 20,400 immigrants with pending cases before the Boston asylum office, according to the American Immigration Lawyers Association’s New England chapter, and those cases are impacted by the low grant rate and issues surrounding it.

The letter is based off the findings of a March 2022 report issued by the ACLU of Maine, University of Maine School of Law's Refugee and Human Rights Clinic, Immigrant Legal Advocacy Project, and Dr. Basileus Zeno, a lecturer at Amherst College who applied for asylum in Boston after fleeing the regime of Bashar al-Assad in Syria. Zeno was ultimately denied after over six years of confusion, and moved to Canada with family before the asylum office contacted him to reopen the case.

The study, titled “Lives in Limbo,” found the Boston office is “dominated by a culture of suspicion and distrust toward asylum seekers,” bias, and “compassion fatigue." It found the Boston asylum office sends cases to immigration court, a longer process with other hurdles, instead of adjudicating them in-house.

The report also alleged the asylum office was "recycling" decisions, whereby an officer would plug new details into old cases instead of offering a new assessment at the end of each person’s case. The report also said that Black immigrants often faced even lower grant rates. Angolan immigrants and those from the Democratic Republic of Congo had grant rates of 2 and 4% respectively, while in Newark’s asylum office, those rates were 17 and 33%.

“There’s been little out of the Boston asylum office responding to our report,” said Anne Welch, director of Maine Law’s Refugee and Human Rights Clinic, who was part of a group that sued USCIS when the agency didn’t initially release public records about applications and grant rates. The report is based off the data they won in court.

Welch told GBH News the group is pleased legislators are calling for an investigation, since that was a “key part” of the solutions section of the report.

This story has been updated to add a statment from the U.S. Citizenship and Immigration Services.