Updated

Federal investigators said Wednesday they have found credible evidence that male supervisors and staff in the maintenance division at Yellowstone National Park created a work environment that included unwelcome and inappropriate comments and actions toward women.

The Interior Department's inspector general concluded that the division's supervisor should have known about and addressed some of the alleged misconduct.

The investigation began last September after a magazine article in which a park employee had complained that a pervasive "men's club" environment at Yellowstone had encouraged the exploitation and abuse of female workers.

At about the same time, a congressional hearing revealed allegations of sexual harassment, bullying and other misconduct at other national parks, including Yosemite and the Grand Canyon.

TOP MARINE GRILLED BY LAWMAKERS OVER NUDE PHOTO SCANDAL

The report on Yellowstone said more than 100 current and former employees were interviewed and 500-plus documents were reviewed, including this past year's exit survey of more than 200 seasonal Yellowstone employees. Overall, the report said that between 2010 and 2016, six women who had previously worked in the maintenance unit had been subjected to derogatory comments or actions that made them feel uncomfortable.

Most employees interviewed — male and female — have told investigators they had not personally experienced or witnessed sexual harassment at the park.

Investigators also reviewed allegations that the maintenance supervisor had groped a female employee, but the employee said the supervisor had never touched her inappropriately or made her uncomfortable.

In reviewing allegations about a "men's club" environment within the maintenance division, the report said the division's supervisor described the culture at Yellowstone as a "good old boy system." The supervisor said such a culture was rampant in the 1990s but that it has improved over time.

Dan Wenk, superintendent of Yellowstone National Park, said in response to the inspector general's report that appropriate, professional behavior is expected from all employees.

"Serious problems were identified within Yellowstone's Maintenance Division, which we take seriously and will be addressing," Wenk said. "Many of the original allegations were found by the OIG to be inaccurate or exaggerated."