Complaints of sexual harassment and hostile workplaces in the National Park Service have spread to Yosemite and Yellowstone, two of the crown jewels in the system, lawmakers disclosed Thursday as they berated a top agency manager for failing to punish wrongdoers.

At a hearing awash in denunciations by unified Democrats and Republicans that sexual misconduct is not taken seriously, House Oversight and Government Reform Committee Chairman Jason Chaffetz (R-Utah) said 18 employees at Yosemite National Park have come forward with allegations of harassment, bullying and a hostile work environment.

Park Service law enforcement officials who investigated the cases before the Interior Department inspector general’s office took over wrote in an internal report, “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 cited the report, which is not public.

Deputy Inspector General Mary Kendall’s office also is investigating claims that women in the maintenance division at Yellowstone National Park were subjected for years to sexual harassment by their supervisors, one of whom is alleged to have paid a laborer on the park staff for sex. The allegations were reported this month by Montana Pioneer, which quoted an engineering-equipment operator employed by the park.

Chaffetz called the accusations “so alarming you would expect the Washington office to come in immediately and make sure things are safe.”

Perhaps the hearing’s most compelling moments came from two whistleblowers, both managers, one who described repeated sexual advances by supervisors and colleagues at the Grand Canyon and the other who said women who work for him at the same park were subjected to similar behavior that was not taken seriously by the Park Service.

The spreading complaints of sexual misconduct in the park system, where many employees live and work in isolated areas, come as the agency reels from investigations showing years of harassment at the Grand Canyon and Canaveral National Seashore, a small Florida park. The issue has prompted several congressional hearings and calls from some Republican lawmakers for Park Service Director Jonathan Jarvis to resign.

Kelly Martin, Yosemite’s chief of fire and aviation management, said she spoke for many of her female colleagues when she described three cases of harassment in her career.

In one, she said, a park ranger leered at her repeatedly through her bathroom window when she was a young employee at the Grand Canyon. She reported him to her supervisors, who forced the ranger to apologize. But he continued his career with the Park Service with no repercussions, she said, until his recent retirement.

In another, Martin said a male supervisor took photographs of her and kept them above the sun visor in his government car, then tried to kiss her in her office. In the third incident, when she was employed by the U.S. Forest Service, she said, one of her supervisors ran his fingers through her hair while she sat next to him on a couch at a work-sponsored meeting in a private home.

“I feel that I can no longer remain silent,” Martin told lawmakers, describing a “clear failure of management to take action to investigate and advocate on a victim’s behalf.”

Michael Reynolds, the Park Service’s newly appointed deputy director for operations, told the committee he is trying to change a culture in which, he acknowledged, little has been done in the past to address sexual misconduct.

“We want to become a model agency,” he said. “We will become a model agency.”

In June, the Park Service promoted a woman as new superintendent of the Grand Canyon. The agency is requiring online training in harassment prevention for all employees and is setting up confidential hotline for victims to report misconduct.

But pressed to say whether anyone has been fired for sexual misconduct in recent years, Reynolds acknowledged that he could not think of anyone.

He also said that while several Grand Canyon employees are under investigation, none have been fired since the inspector general provided an explosive report to park officials 10 months ago about a culture of harassment in the park’s river district.

“You don’t need a new memo to deal with this,” Rep. Trey Gowdy (R-S.C.) said when Martin described the park ranger who looked through her bathroom window. “You need handcuffs and a trip to the sex-offender registry.”

Brian Healy, fisheries program manager at the Grand Canyon, testified that the supervisor of the river district recently received a temporary promotion to another park where he is now the chief law enforcement ranger. This employee twice breached the confidentiality of the victims who were the subject of the inspector general report, Healy said.

He also told lawmakers that in 2013, one of his fisheries technicians was physically assaulted by a member of the park’s trail maintenance crew and then subjected to harassment and intimidation by other members of the group in retaliation for her reporting the assault to police.

“People are being harassed or worse, and no one is doing anything about it,” Rep. Gerald E. Connolly (D-Va.) said, asking Reynolds, “Is this a  systemic culture?”

“I believe we have a problem,” Reynolds answered. “And we should be making very urgent changes to that culture.”

Rep. Elijah E. Cummings (D-Md.), the committee’s top Democrat, reminded Reynolds that a task force convened by the Park Service 16 years ago to investigate sexual harassment found serious problems and a lack of attention by management.

But none of its multiple recommendations were implemented.

“Obviously the Park Service did not consider it to be that important,” Cummings said. “It was filed away and put on a shelf for gathering dust.”

The Park Service transferred the superintendent of Canaveral National Seashore to a telework job last week, a move the watchdog group Public Employees for Environmental Responsibility called a “kick upstairs to a non-job.”

Yellowstone Superintendent Dan Wenk said in an email that he became aware in early September of the allegations in the maintenance division “and immediately took steps to investigate.”

The inspector general’s office is sending investigators next week.

“We will cooperate fully, and when we receive the findings of the investigation, appropriate action will be taken,” Wenk said.