At a recent hearing on Capitol Hill, House Oversight and Government Reform Committee Chairman Jason Chaffetz (R-Utah) read aloud a shocking excerpt from an internal investigation of multiple allegations of a hostile workplace at Yosemite National Park.

“The number of employees interviewed that described horrific working conditions lead us to believe that the environment is indeed toxic, hostile, repressive and harassing,” Chaffetz read as he described an environment in which employees, particularly women, are bullied and harassed at one of America’s most beloved national parks.

The investigation, after more than 18 employees complained of a toxic workplace, has not been made public. The National Park Service only let the committee staff see it once to take notes, but they were not allowed to keep a copy.

Now the committee’s top Republicans and Democrats are demanding a copy of the investigation they can read and make public — and threatening a rare subpoena if the Park Service does not cooperate.

In a letter Wednesday to Michael Reynolds, the agency’s deputy director for operations, the lawmakers demanded the complete, unredacted report and supporting documents. They also want to know the number of Park Service employees who have been fired for sexual harassment or similar misconduct since 2013 and the number of complaints employees have filed during the same period alleging the same misconduct.

“The documents and information you promised to provide relate to the safety and well being of NPS employees,” said the one-page letter signed by Chaffetz and top committee Democrat Elijah E. Cummings (Md.), as well as Rep. Cynthia M. Lummis (R-Wyo.) and Rep. Brenda Lawrence (D-Mich.), the chairman and ranking Democrat, respectively, on the subcommittee that oversees the Park Service.

Park Service spokesman Thomas Crosson said in an email, “We are in receipt of the committee’s memo and we are in the process of verifying the information they requested.”

In recent months, lawmakers have exerted bipartisan pressure on the Park Service to address a widening scandal that broke open nine months ago with revelations that multiple women who work at the Grand Canyon were bullied and propositioned by fellow male employees on river trips, then retaliated against when they complained of the harassment.

Similar allegations, some already backed up by investigations by the Interior Department inspector general, quickly widened to other parks, including Canaveral National Seashore and Yellowstone, where investigators are now conducting interviews.

The themes from employees and investigators are similar at the Grand Canyon, Yosemite and Canaveral: Top park managers failed to act when they knew employees were subjected to misconduct.

The pressure, both from Congress and Interior Secretary Sally Jewell, led the Park Service to act swiftly last week to force out Yosemite Superintendent Don Neubacher after a career with the agency.

“In order to preserve the integrity of the ongoing investigation into allegations of a hostile work environment at Yosemite National Park, the National Park Service acted to move Don Neubacher from his role” at the park, agency spokesman Andrew Munoz said in a forthright statement.

By deposing Neubacher in the midst of a more thorough follow-up investigation at Yosemite by the inspector general’s office, the Park Service is showing that a culture many have criticized for protecting managers has to change.

The action against Neubacher — who chose to retire Nov. 1 rather than accept an assignment at another park — is a glaring contrast with how the Park Service handled the case of former Grand Canyon superintendent Dave Uberuaga, whom investigators accused of failing to look into and report allegations of misconduct.

Uberuaga, like Neubacher, was not fired but offered a job at the Park Service’s Washington headquarters instead. He retired June 1, fully seven months after the Park Service received a copy of the investigation.

At the Sept. 22 congressional hearing, Kelly Martin, Yosemite’s fire chief, testified that Neubacher had publicly humiliated her and intimidated her colleagues. He apologized to all park employees in an email, acknowledging “some serious staff concerns related to Yosemite’s workplace environment.”

On Monday, Neubacher’s wife, Patty, announced her sudden retirement from her post as deputy regional director for the Pacific West Region, which includes Yosemite. Some employees — and lawmakers — alleged that while she did not directly supervise her husband, she had used her position to protect him.

“You have somebody on your staff who is essentially protected and empowered by his wife,” Chaffetz had asked Reynolds at the hearing. “How do you let that happen?”