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House Democrats are pushing for the ability to drop by immigration detention centers and check out the conditions — an opportunity that has repeatedly eluded some legislators in the past.

Colorado Rep. Jason Crow, a freshman Democrat, is leading the charge, joined by progressives like Reps. Alexandria Ocasio-Cortez and Ayanna Pressley. The group of 20 Democrats sent a letter to the House Appropriations Subcommittee for Homeland Security on Friday that asks to include language in a budget bill that would allow them to tour Immigration and Customs Enforcement detention facilities with 48-hour notice.

The proposal would block federal money from being “used to prevent a member of Congress from entering” a facility funded by the Department of Homeland Security or change a facility in some way prior to a congressional visit.

In the past, similar visits have taken weeks to organize, and several legislators have been denied access altogether. In February, Crow was turned away from an adult immigration detention facility in Aurora, Colorado, after he asked for a walk-through to learn more about the health care resources available to stem a chickenpox outbreak among its 1,500-plus detainees. At least one detainee had also been diagnosed with mumps, an illness that quarantined 2,200 migrants at the Colorado facility and a similar detention center in Louisiana.

Detainees at other adult immigration facilities have also reported abuse, a dire lack of medical care, and inadequate access to legal resources.

“It is vital members of Congress are able to do what they can to ensure safe and secure detention environments for staff, detainees and their surrounding communities,” the letter reads.

Members of Congress are already allowed to drop-in on detention facilities for unaccompanied migrant children. If the proposed language becomes part of the budget bill, it’d almost certainly pass the House, but it’s uncertain whether the Republican-controlled Senate would keep the amendment.

Crow said he was concerned after he heard that the Aurora facility hired only one in-house physician to treat the detainees, who were blocked from visiting their lawyers while they’re sick. A field office director from ICE told VICE News at the time that Crow was only turned away from a visit because he hadn’t made a prior appointment. He subsequently wrote a letter to former Homeland Security Secretary Kirstjen Nielsen asking why the facility lacked enough in-house physicians, but he said hasn’t yet received an answer yet.

In the meantime, detainees at the facility went on a hunger strike to protest the quarantine.

Crow told VICE News he was able to visit the Aurora facility on March 15, nearly 25 days after he made his first request to ICE. He noticed a new coat of paint on the walls — but English-only books in the facility’s legal library.

“This is an agency that is not accustomed to oversight, especially under the last two years under the prior Congress,” Crow said. “We’re in a new era now.”

In July, then-Rep Jeff Denham also wasn’t let into a child detention center and alleged employees there weren’t allowed to speak to him because he hadn’t provided two weeks notice before the visit. In January 2018, Democratic Sen. Jeff Merkley was blocked from entering a detention center in south Texas, although he was eventually allowed to look around the facility a few weeks later.

During a hunger strike at an El Paso-based detention facility in January, ICE employees also began force-feeding nine detainees on a federal judge’s orders. Rep. Veronica Escobar, a Democrat from Texas, immediately demanded entry to the facility after news of the hunger strike broke in February, and she's since requested a probe into the facility.