WASHINGTON — Thousands of the Interior Department’s employees reported that they had experienced harassment or intimidation at work, a department-wide survey conducted earlier this year and released Thursday found.

Of the nearly 30,000 employees who reported on their experiences, about 35 percent said they felt some form of harassment and intimidation, often related to their age or gender. More than 85 percent of those employees said they had to continue to interact with the person responsible for the mistreatment.

“This is a breach of public trust,” said Interior Secretary Ryan Zinke in an interview, adding that he had personally fired four people over accusations of harassment. “Harassment — intimidation — is a cancer that can destroy even the best organizations.”

In the survey, 8 percent of employees reported sexual harassment, 20 percent reported negative treatment based on their age and 16 percent based on their sex. About 44 percent of the department’s 70,000 employees responded to the survey.